reduce 125VAC to 120VAC, small form factor, and clean 60Hz s

[ScottWW]

Two occasional (electrical) causes of hum in electric motors (specifically
ceiling fans) are overvoltage and a noisy sine-wave.

If a US home is measured over 127VAC the local power utility will often
install a line conditioner. If a home is measured at 125VAC, in most cases
the power utility states that it is "within tolerances".

Tracking the source of line noise on 120VAC is often trial and error and
cannot always identify a single culprit. O'scopes are not commonly carried
by the installers. But I have documented a few overvoltage situations where
the line noise was also present; and I suspect creating some of the measured
overrvoltage.

I would like a device, that can reduce 125VAC voltage by 10% while
maintaining a smooth sine waveform. The last time I researched 120V
transformers for a 10% voltage reduction, they were too large (4"x 4" x 4")
for my purposes. Optimally I would like to this device to fit within a
"pancake box" outlet box, but even a 4" octagon outlet box.

Are there any new developments in small sized transformers capable of doing
this?
Does anybody have any ideas how else this could be accomplished?

Thanks!
Scott
Dunedin FL

 

[Jim Thompson]

On Tue, 2 Apr 2013 16:47:02 -0400, "ScottWW" <spamtrap@dcorp.com>
wrote:

Two occasional (electrical) causes of hum in electric motors (specifically
ceiling fans) are overvoltage and a noisy sine-wave.

If a US home is measured over 127VAC the local power utility will often
install a line conditioner. If a home is measured at 125VAC, in most cases
the power utility states that it is "within tolerances".

Tracking the source of line noise on 120VAC is often trial and error and
cannot always identify a single culprit. O'scopes are not commonly carried
by the installers. But I have documented a few overvoltage situations where
the line noise was also present; and I suspect creating some of the measured
overrvoltage.

I would like a device, that can reduce 125VAC voltage by 10% while
maintaining a smooth sine waveform. The last time I researched 120V
transformers for a 10% voltage reduction, they were too large (4"x 4" x 4")
for my purposes. Optimally I would like to this device to fit within a
"pancake box" outlet box, but even a 4" octagon outlet box.

Are there any new developments in small sized transformers capable of doing
this?
Does anybody have any ideas how else this could be accomplished?

Thanks!
Scott
Dunedin FL

There was recent thread on S.E.D...

"Mains wiring question: Sizing buck-boost transformer?"

Starting with Message-ID:
<0001HW.CD7B40B60050CF9CB01029BF@news.eternal-september.org>

that addresses your very problem.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Tim Wescott]

On Tue, 02 Apr 2013 16:47:02 -0400, ScottWW wrote:

Two occasional (electrical) causes of hum in electric motors
(specifically ceiling fans) are overvoltage and a noisy sine-wave.

If a US home is measured over 127VAC the local power utility will often
install a line conditioner. If a home is measured at 125VAC, in most
cases the power utility states that it is "within tolerances".

Tracking the source of line noise on 120VAC is often trial and error and
cannot always identify a single culprit. O'scopes are not commonly
carried by the installers. But I have documented a few overvoltage
situations where the line noise was also present; and I suspect creating
some of the measured overrvoltage.

I would like a device, that can reduce 125VAC voltage by 10% while
maintaining a smooth sine waveform. The last time I researched 120V
transformers for a 10% voltage reduction, they were too large (4"x 4" x
4") for my purposes. Optimally I would like to this device to fit
within a "pancake box" outlet box, but even a 4" octagon outlet box.

Are there any new developments in small sized transformers capable of
doing this?
Does anybody have any ideas how else this could be accomplished?

Thanks!
Scott
Dunedin FL

It depends on the current you need it to carry -- lower current = smaller
size. What current are you asking of it?

If you want a traditional transformer with iron laminates and wire
windings then there's a pretty strict volume vs. volt-amp rating that has
to be adhered to, which is limited by the physics of copper wire and
magnetic steel. Making one that's a pancake shape just complicates the
transformer design and (probably) increases the volume even as you get
the thickness smaller.

Note that the fact that you want to install these in electrical boxes
complicates things -- you need something that'll be compliant to wiring
codes so it'll pass inspection. So you have legal hoops to jump through,
too. And of course if you select some 5V power supply transformer to use
in buck and some dip s**t burns down their house or gets electrocuted
through ordinary human stupidity, his/her kin will hire a lawyer who will
blame you and try to extract $$$ from you.

I assume that you're a professional fan installer who's at the mercy of
the ceiling fan manufacturers. Given that you're not going to like what
I have to say, but here's my ever so humble opinion:

If you're selling a product (like a ceiling fan) into a market where the
line voltages commonly go above 125V and are commonly dirty, and if you
make your ceiling fan so that it makes objectionable noises when these
commonly occurring conditions prevail, then you are making a poor product
and the best you deserve is to have your customers let you know why they
are abandoning you to other vendors.

If you're a manufacturer, ditto.

If you're an installer, you should be looking for a different
manufacturer to favor. Only if this problem exists across the whole
market, or if there's some compelling reason to avoid the fans that don't
hum at high voltages (like they're otherwise pieces of s**t or
something), should you try to fix the problem with bubble gum, spit, or
transformers in electrical boxes.

If _all_ the manufacturers out there are stupid, then there may be a
market opportunity here to make and sell these things. Of course, as
soon as you get really successful the ceiling fan manufacturers will have
lights go on in the dimness that dominates their brains and will realize
that there's money to be made in fans that don't hum, and they'll start
doing so and take away your business.

And it may be cheaper to just make your own damn fans.

Were it me and I did it, I'd sell out to the first ceiling fan
manufacturer that came sniffing around with enough cash to make it worth
my while -- because I would know that if I didn't, the next thing I'd see
would be "humless fans" on the market, and a big investment in useless
transformers sitting in unsellable piles in the soon-to-be-not-mine
business.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

 

[Jim Thompson]

On Tue, 02 Apr 2013 17:53:07 -0500, Tim Wescott <tim@seemywebsite.com>
wrote:

On Tue, 02 Apr 2013 16:47:02 -0400, ScottWW wrote:

Two occasional (electrical) causes of hum in electric motors
(specifically ceiling fans) are overvoltage and a noisy sine-wave.

If a US home is measured over 127VAC the local power utility will often
install a line conditioner. If a home is measured at 125VAC, in most
cases the power utility states that it is "within tolerances".

Tracking the source of line noise on 120VAC is often trial and error and
cannot always identify a single culprit. O'scopes are not commonly
carried by the installers. But I have documented a few overvoltage
situations where the line noise was also present; and I suspect creating
some of the measured overrvoltage.

I would like a device, that can reduce 125VAC voltage by 10% while
maintaining a smooth sine waveform. The last time I researched 120V
transformers for a 10% voltage reduction, they were too large (4"x 4" x
4") for my purposes. Optimally I would like to this device to fit
within a "pancake box" outlet box, but even a 4" octagon outlet box.

Are there any new developments in small sized transformers capable of
doing this?
Does anybody have any ideas how else this could be accomplished?

Thanks!
Scott
Dunedin FL

It depends on the current you need it to carry -- lower current = smaller
size. What current are you asking of it?

If you want a traditional transformer with iron laminates and wire
windings then there's a pretty strict volume vs. volt-amp rating that has
to be adhered to, which is limited by the physics of copper wire and
magnetic steel. Making one that's a pancake shape just complicates the
transformer design and (probably) increases the volume even as you get
the thickness smaller.

Note that the fact that you want to install these in electrical boxes
complicates things -- you need something that'll be compliant to wiring
codes so it'll pass inspection. So you have legal hoops to jump through,
too. And of course if you select some 5V power supply transformer to use
in buck and some dip s**t burns down their house or gets electrocuted
through ordinary human stupidity, his/her kin will hire a lawyer who will
blame you and try to extract $$$ from you.

I assume that you're a professional fan installer who's at the mercy of
the ceiling fan manufacturers. Given that you're not going to like what
I have to say, but here's my ever so humble opinion:

If you're selling a product (like a ceiling fan) into a market where the
line voltages commonly go above 125V and are commonly dirty, and if you
make your ceiling fan so that it makes objectionable noises when these
commonly occurring conditions prevail, then you are making a poor product
and the best you deserve is to have your customers let you know why they
are abandoning you to other vendors.

If you're a manufacturer, ditto.

If you're an installer, you should be looking for a different
manufacturer to favor. Only if this problem exists across the whole
market, or if there's some compelling reason to avoid the fans that don't
hum at high voltages (like they're otherwise pieces of s**t or
something), should you try to fix the problem with bubble gum, spit, or
transformers in electrical boxes.

If _all_ the manufacturers out there are stupid, then there may be a
market opportunity here to make and sell these things. Of course, as
soon as you get really successful the ceiling fan manufacturers will have
lights go on in the dimness that dominates their brains and will realize
that there's money to be made in fans that don't hum, and they'll start
doing so and take away your business.

And it may be cheaper to just make your own damn fans.

Were it me and I did it, I'd sell out to the first ceiling fan
manufacturer that came sniffing around with enough cash to make it worth
my while -- because I would know that if I didn't, the next thing I'd see
would be "humless fans" on the market, and a big investment in useless
transformers sitting in unsellable piles in the soon-to-be-not-mine
business.

Used Popsicle sticks fix _many_ problems ;-)

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Jamie]

ScottWW wrote:

Two occasional (electrical) causes of hum in electric motors (specifically
ceiling fans) are overvoltage and a noisy sine-wave.

If a US home is measured over 127VAC the local power utility will often
install a line conditioner. If a home is measured at 125VAC, in most cases
the power utility states that it is "within tolerances".

Tracking the source of line noise on 120VAC is often trial and error and
cannot always identify a single culprit. O'scopes are not commonly carried
by the installers. But I have documented a few overvoltage situations
where
the line noise was also present; and I suspect creating some of the
measured
overrvoltage.

I would like a device, that can reduce 125VAC voltage by 10% while
maintaining a smooth sine waveform. The last time I researched 120V
transformers for a 10% voltage reduction, they were too large (4"x 4" x 4")
for my purposes. Optimally I would like to this device to fit within a
"pancake box" outlet box, but even a 4" octagon outlet box.

Are there any new developments in small sized transformers capable of doing
this?
Does anybody have any ideas how else this could be accomplished?

Thanks!
Scott
Dunedin FL

A line reactor may quiet it down a bit. You can find those where they

sell accessories for drives and motors. It's possible some one near you
on the same pole pig could be operating a welder or similar, if this is
intermitting.

P.S.
That little over voltage isn't going to cause noise, a distorted
wave form will.

Jamie

 

[ScottWW]

"Jim Thompson" wrote in message
news:8qhml8hr2ib6g1olla6du6t3ubdv5doouo@4ax.com...

On Tue, 2 Apr 2013 16:47:02 -0400, "ScottWW" <spamtrap@dcorp.com>
wrote:

Two occasional (electrical) causes of hum in electric motors (specifically
ceiling fans) are overvoltage and a noisy sine-wave.

If a US home is measured over 127VAC the local power utility will often
install a line conditioner. If a home is measured at 125VAC, in most cases
the power utility states that it is "within tolerances".

Tracking the source of line noise on 120VAC is often trial and error and
cannot always identify a single culprit. O'scopes are not commonly carried
by the installers. But I have documented a few overvoltage situations
where
the line noise was also present; and I suspect creating some of the
measured
overrvoltage.

I would like a device, that can reduce 125VAC voltage by 10% while
maintaining a smooth sine waveform. The last time I researched 120V
transformers for a 10% voltage reduction, they were too large (4"x 4" x 4")
for my purposes. Optimally I would like to this device to fit within a
"pancake box" outlet box, but even a 4" octagon outlet box.

Are there any new developments in small sized transformers capable of doing
this?
Does anybody have any ideas how else this could be accomplished?

Thanks!
Scott
Dunedin FL

There was recent thread on S.E.D...

"Mains wiring question: Sizing buck-boost transformer?"

Starting with Message-ID:
<0001HW.CD7B40B60050CF9CB01029BF@news.eternal-september.org>

that addresses your very problem.

...Jim Thompson
*******************
Thanks,
I am reading further...

 

[ScottWW]

"Jamie" wrote in message news:eAJ6t.93922$Xw1.89106@newsfe20.iad...

ScottWW wrote:

Two occasional (electrical) causes of hum in electric motors (specifically
ceiling fans) are overvoltage and a noisy sine-wave.

If a US home is measured over 127VAC the local power utility will often
install a line conditioner. If a home is measured at 125VAC, in most
cases
the power utility states that it is "within tolerances".

Tracking the source of line noise on 120VAC is often trial and error and
cannot always identify a single culprit. O'scopes are not commonly
carried
by the installers. But I have documented a few overvoltage situations
where
the line noise was also present; and I suspect creating some of the
measured
overrvoltage.

I would like a device, that can reduce 125VAC voltage by 10% while
maintaining a smooth sine waveform. The last time I researched 120V
transformers for a 10% voltage reduction, they were too large (4"x 4" x
4")
for my purposes. Optimally I would like to this device to fit within a
"pancake box" outlet box, but even a 4" octagon outlet box.

Are there any new developments in small sized transformers capable of
doing
this?
Does anybody have any ideas how else this could be accomplished?

Thanks!
Scott
Dunedin FL

A line reactor may quiet it down a bit. You can find those where they

sell accessories for drives and motors. It's possible some one near you
on the same pole pig could be operating a welder or similar, if this is
intermitting.

P.S.
That little over voltage isn't going to cause noise, a distorted
wave form will.

Jamie
*****************
Thanks!
I was not aware of this device. I am reading further.

 

[ScottWW]

"Tim Wescott" wrote in message
news:Zt6dnRbim-vO_MbMnZ2dnUVZ_rSdnZ2d@giganews.com...

On Tue, 02 Apr 2013 16:47:02 -0400, ScottWW wrote:

Two occasional (electrical) causes of hum in electric motors
(specifically ceiling fans) are overvoltage and a noisy sine-wave.

If a US home is measured over 127VAC the local power utility will often
install a line conditioner. If a home is measured at 125VAC, in most
cases the power utility states that it is "within tolerances".

Tracking the source of line noise on 120VAC is often trial and error and
cannot always identify a single culprit. O'scopes are not commonly
carried by the installers. But I have documented a few overvoltage
situations where the line noise was also present; and I suspect creating
some of the measured overrvoltage.

I would like a device, that can reduce 125VAC voltage by 10% while
maintaining a smooth sine waveform. The last time I researched 120V
transformers for a 10% voltage reduction, they were too large (4"x 4" x
4") for my purposes. Optimally I would like to this device to fit
within a "pancake box" outlet box, but even a 4" octagon outlet box.

Are there any new developments in small sized transformers capable of
doing this?
Does anybody have any ideas how else this could be accomplished?

Thanks!
Scott
Dunedin FL

It depends on the current you need it to carry -- lower current = smaller
size. What current are you asking of it?

If you want a traditional transformer with iron laminates and wire
windings then there's a pretty strict volume vs. volt-amp rating that has
to be adhered to, which is limited by the physics of copper wire and
magnetic steel. Making one that's a pancake shape just complicates the
transformer design and (probably) increases the volume even as you get
the thickness smaller.

Note that the fact that you want to install these in electrical boxes
complicates things -- you need something that'll be compliant to wiring
codes so it'll pass inspection. So you have legal hoops to jump through,
too. And of course if you select some 5V power supply transformer to use
in buck and some dip s**t burns down their house or gets electrocuted
through ordinary human stupidity, his/her kin will hire a lawyer who will
blame you and try to extract $$$ from you.

I assume that you're a professional fan installer who's at the mercy of
the ceiling fan manufacturers. Given that you're not going to like what
I have to say, but here's my ever so humble opinion:

If you're selling a product (like a ceiling fan) into a market where the
line voltages commonly go above 125V and are commonly dirty, and if you
make your ceiling fan so that it makes objectionable noises when these
commonly occurring conditions prevail, then you are making a poor product
and the best you deserve is to have your customers let you know why they
are abandoning you to other vendors.

If you're a manufacturer, ditto.

If you're an installer, you should be looking for a different
manufacturer to favor. Only if this problem exists across the whole
market, or if there's some compelling reason to avoid the fans that don't
hum at high voltages (like they're otherwise pieces of s**t or
something), should you try to fix the problem with bubble gum, spit, or
transformers in electrical boxes.

If _all_ the manufacturers out there are stupid, then there may be a
market opportunity here to make and sell these things. Of course, as
soon as you get really successful the ceiling fan manufacturers will have
lights go on in the dimness that dominates their brains and will realize
that there's money to be made in fans that don't hum, and they'll start
doing so and take away your business.

And it may be cheaper to just make your own damn fans.

Were it me and I did it, I'd sell out to the first ceiling fan
manufacturer that came sniffing around with enough cash to make it worth
my while -- because I would know that if I didn't, the next thing I'd see
would be "humless fans" on the market, and a big investment in useless
transformers sitting in unsellable piles in the soon-to-be-not-mine
business.

***************************
Thanks for your reply. Your faint hostility towards ceiling fan
manufacturers aside, you bring up some valid points and concerns. As a
distributor with close ties to a couple manufacturers producing our
products, I may be defensive in my reading. My intent is not to profit from
the multitudes of crappy fans; my intent is a solution that maintains
customer satisfaction even where more power is desired. I unfortunately
have become the last stop in customer service escalation.

The typical amperage of a fan motor is 0.7A at 120V, max 1.25A for the
largest motors (permanent split capacitor induction motors).
The overvoltage hum only occurs on the larger, heavier motors that are the
more powerful air movers.

The overvoltages are not 'commonly' occurring conditions. That is why I
seek a modular solution, as they would only be needed in a fraction of a
percent of cases. These cases are invariably from electrician installed
fans, so I am not really looking for homeowner installed solution, though
the "fit into an outlet box" size certain would be more convenient for the
DIYer.

We have documented many causes of audible motor hum of the past few decades,
and most can be solved by simple solutions - tightening screws, the use of a
proper control (dimmers truncate the sine wave peaks), or
reinforcement/tightening of the installation site (extruded metal
beams/studs, split wood in beams/rafters, and torsion-box-built ceilings,
all transmit vibrations). Only the ones found to be overvoltage/line noise
issues are currently without solution, unless the utility helps out.

Scott
Dunedin FL

 

[John Larkin]

On Tue, 2 Apr 2013 16:47:02 -0400, "ScottWW" <spamtrap@dcorp.com> wrote:

Two occasional (electrical) causes of hum in electric motors (specifically
ceiling fans) are overvoltage and a noisy sine-wave.

A cheapish motor may saturate at high line voltage and create its own harmonics.

A series inductor would be a good fix for both sorts of problems. It would
reduce the motor voltage and somewhat filter external harmonics. A series cap
would help with the over-voltage but not externals.

Ceiling fans are great (we have no air conditioning in San Francisco and it does
get warm once in a while) as long as they are quiet.



--

John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

 

[ScottWW]

"John Larkin" wrote in message
news:fmkol855vrrjgo6tvge7eg2tbhngseicbl@4ax.com...

On Tue, 2 Apr 2013 16:47:02 -0400, "ScottWW" <spamtrap@dcorp.com> wrote:

Two occasional (electrical) causes of hum in electric motors (specifically
ceiling fans) are overvoltage and a noisy sine-wave.

A cheapish motor may saturate at high line voltage and create its own
harmonics.

A series inductor would be a good fix for both sorts of problems. It would
reduce the motor voltage and somewhat filter external harmonics. A series
cap
would help with the over-voltage but not externals.

Ceiling fans are great (we have no air conditioning in San Francisco and it
does
get warm once in a while) as long as they are quiet.

***************
Thank you for the reply. Jamie's reply to my post mentioned a Line Reactor
which appears to incorporate a series of inductors. I am reading more about
this now. I have suspected line noise is the true culprit and overvoltage
is a side-effect.

Core saturation in the motor has been discussed in the past with the
manufacturers (regarding heat rise), but the motors are designed to operate
at the median of saturation (at the normal voltage range) to limit heat
rise. I will bring this idea up again in regards to noise.

Scott

 

[Jim Thompson]

On Wed, 3 Apr 2013 17:40:23 +0000 (UTC), Cydrome Leader
<presence@MUNGEpanix.com> wrote:

ScottWW <spamtrap@dcorp.com> wrote:
"Jim Thompson" wrote in message
news:8qhml8hr2ib6g1olla6du6t3ubdv5doouo@4ax.com...

On Tue, 2 Apr 2013 16:47:02 -0400, "ScottWW" <spamtrap@dcorp.com
wrote:

Two occasional (electrical) causes of hum in electric motors (specifically
ceiling fans) are overvoltage and a noisy sine-wave.

If a US home is measured over 127VAC the local power utility will often
install a line conditioner. If a home is measured at 125VAC, in most cases
the power utility states that it is "within tolerances".

Tracking the source of line noise on 120VAC is often trial and error and
cannot always identify a single culprit. O'scopes are not commonly carried
by the installers. But I have documented a few overvoltage situations
where
the line noise was also present; and I suspect creating some of the
measured
overrvoltage.

I would like a device, that can reduce 125VAC voltage by 10% while
maintaining a smooth sine waveform. The last time I researched 120V
transformers for a 10% voltage reduction, they were too large (4"x 4" x 4")
for my purposes. Optimally I would like to this device to fit within a
"pancake box" outlet box, but even a 4" octagon outlet box.

Are there any new developments in small sized transformers capable of doing
this?
Does anybody have any ideas how else this could be accomplished?

Thanks!
Scott
Dunedin FL

There was recent thread on S.E.D...

"Mains wiring question: Sizing buck-boost transformer?"

Starting with Message-ID:
0001HW.CD7B40B60050CF9CB01029BF@news.eternal-september.org

that addresses your very problem.

...Jim Thompson
*******************
Thanks,
I am reading further...


You'll probably be breaking all sorts of codes, but an 8 volt doorbell
transformer might do what you want, if wired in buck mode. You'd want to
hide that in a box of some sort as there would be line voltage at the
screw terminals. Even if you wire the neutral to the low voltage side,
it's a nonstandard use and you don't want to confuse anybody. It might fit
in a deep two gang box.

I doubt that a doorbell transformer has sufficient KVA, but they're
generally box mountable and meet code, being metal enclosed and with a
stub that fits box knock-outs... at least here in AZ, no exposed screw
terminals.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Cydrome Leader]

ScottWW <spamtrap@dcorp.com> wrote:

"Jim Thompson" wrote in message
news:8qhml8hr2ib6g1olla6du6t3ubdv5doouo@4ax.com...

On Tue, 2 Apr 2013 16:47:02 -0400, "ScottWW" <spamtrap@dcorp.com
wrote:

Two occasional (electrical) causes of hum in electric motors (specifically
ceiling fans) are overvoltage and a noisy sine-wave.

If a US home is measured over 127VAC the local power utility will often
install a line conditioner. If a home is measured at 125VAC, in most cases
the power utility states that it is "within tolerances".

Tracking the source of line noise on 120VAC is often trial and error and
cannot always identify a single culprit. O'scopes are not commonly carried
by the installers. But I have documented a few overvoltage situations
where
the line noise was also present; and I suspect creating some of the
measured
overrvoltage.

I would like a device, that can reduce 125VAC voltage by 10% while
maintaining a smooth sine waveform. The last time I researched 120V
transformers for a 10% voltage reduction, they were too large (4"x 4" x 4")
for my purposes. Optimally I would like to this device to fit within a
"pancake box" outlet box, but even a 4" octagon outlet box.

Are there any new developments in small sized transformers capable of doing
this?
Does anybody have any ideas how else this could be accomplished?

Thanks!
Scott
Dunedin FL

There was recent thread on S.E.D...

"Mains wiring question: Sizing buck-boost transformer?"

Starting with Message-ID:
0001HW.CD7B40B60050CF9CB01029BF@news.eternal-september.org

that addresses your very problem.

...Jim Thompson
*******************
Thanks,
I am reading further...

You'll probably be breaking all sorts of codes, but an 8 volt doorbell
transformer might do what you want, if wired in buck mode. You'd want to
hide that in a box of some sort as there would be line voltage at the
screw terminals. Even if you wire the neutral to the low voltage side,
it's a nonstandard use and you don't want to confuse anybody. It might fit
in a deep two gang box.

 

[Jim Thompson]

On Wed, 3 Apr 2013 21:16:05 +0000 (UTC), Cydrome Leader
<presence@MUNGEpanix.com> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@on-my-web-site.com> wrote:
On Wed, 3 Apr 2013 17:40:23 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

ScottWW <spamtrap@dcorp.com> wrote:
"Jim Thompson" wrote in message
news:8qhml8hr2ib6g1olla6du6t3ubdv5doouo@4ax.com...

On Tue, 2 Apr 2013 16:47:02 -0400, "ScottWW" <spamtrap@dcorp.com
wrote:

Two occasional (electrical) causes of hum in electric motors (specifically
ceiling fans) are overvoltage and a noisy sine-wave.

If a US home is measured over 127VAC the local power utility will often
install a line conditioner. If a home is measured at 125VAC, in most cases
the power utility states that it is "within tolerances".

Tracking the source of line noise on 120VAC is often trial and error and
cannot always identify a single culprit. O'scopes are not commonly carried
by the installers. But I have documented a few overvoltage situations
where
the line noise was also present; and I suspect creating some of the
measured
overrvoltage.

I would like a device, that can reduce 125VAC voltage by 10% while
maintaining a smooth sine waveform. The last time I researched 120V
transformers for a 10% voltage reduction, they were too large (4"x 4" x 4")
for my purposes. Optimally I would like to this device to fit within a
"pancake box" outlet box, but even a 4" octagon outlet box.

Are there any new developments in small sized transformers capable of doing
this?
Does anybody have any ideas how else this could be accomplished?

Thanks!
Scott
Dunedin FL

There was recent thread on S.E.D...

"Mains wiring question: Sizing buck-boost transformer?"

Starting with Message-ID:
0001HW.CD7B40B60050CF9CB01029BF@news.eternal-september.org

that addresses your very problem.

...Jim Thompson
*******************
Thanks,
I am reading further...


You'll probably be breaking all sorts of codes, but an 8 volt doorbell
transformer might do what you want, if wired in buck mode. You'd want to
hide that in a box of some sort as there would be line voltage at the
screw terminals. Even if you wire the neutral to the low voltage side,
it's a nonstandard use and you don't want to confuse anybody. It might fit
in a deep two gang box.


I doubt that a doorbell transformer has sufficient KVA, but they're
generally box mountable and meet code, being metal enclosed and with a
stub that fits box knock-outs... at least here in AZ, no exposed screw
terminals.

...Jim Thompson

I've never seen a fully enclosed one around here as they're all screw terminals
staked onto some sort of fishpaper on the LV side, but you have so they must
exist.

I can't honestly say I have any idea how much current a ceiling fan draws, but if
it's just an amp or so, a wimpy doorbell transformer should be OK. Security
camera/alarm system/hvac transformers all seems to be rated too high in voltage,
but do seem to be beefier in power ratings.

I have no idea how much power the fan needs either.

But it seems a transformer contained within a certified electrical box
should be OK, provided that "earth" in maintained IN-to-OUT, maybe add
a GCFI to CYA.

(I've added outlets onto my patio simply by punching thru the wall
from an existing indoor outlet and adding an outdoor-rated receptacle
on the patio side. Then I changed the indoor receptacle to a GCFI
unit with downstream "feed-through" protection.)

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Tim Wescott]

On Wed, 03 Apr 2013 11:58:42 -0400, ScottWW wrote:

"Tim Wescott" wrote in message
news:Zt6dnRbim-vO_MbMnZ2dnUVZ_rSdnZ2d@giganews.com...

On Tue, 02 Apr 2013 16:47:02 -0400, ScottWW wrote:

Two occasional (electrical) causes of hum in electric motors
(specifically ceiling fans) are overvoltage and a noisy sine-wave.

If a US home is measured over 127VAC the local power utility will often
install a line conditioner. If a home is measured at 125VAC, in most
cases the power utility states that it is "within tolerances".

Tracking the source of line noise on 120VAC is often trial and error
and cannot always identify a single culprit. O'scopes are not commonly
carried by the installers. But I have documented a few overvoltage
situations where the line noise was also present; and I suspect
creating some of the measured overrvoltage.

I would like a device, that can reduce 125VAC voltage by 10% while
maintaining a smooth sine waveform. The last time I researched 120V
transformers for a 10% voltage reduction, they were too large (4"x 4" x
4") for my purposes. Optimally I would like to this device to fit
within a "pancake box" outlet box, but even a 4" octagon outlet box.

Are there any new developments in small sized transformers capable of
doing this?
Does anybody have any ideas how else this could be accomplished?

Thanks!
Scott
Dunedin FL

It depends on the current you need it to carry -- lower current =
smaller size. What current are you asking of it?

If you want a traditional transformer with iron laminates and wire
windings then there's a pretty strict volume vs. volt-amp rating that
has to be adhered to, which is limited by the physics of copper wire and
magnetic steel. Making one that's a pancake shape just complicates the
transformer design and (probably) increases the volume even as you get
the thickness smaller.

Note that the fact that you want to install these in electrical boxes
complicates things -- you need something that'll be compliant to wiring
codes so it'll pass inspection. So you have legal hoops to jump
through, too. And of course if you select some 5V power supply
transformer to use in buck and some dip s**t burns down their house or
gets electrocuted through ordinary human stupidity, his/her kin will
hire a lawyer who will blame you and try to extract $$$ from you.

I assume that you're a professional fan installer who's at the mercy of
the ceiling fan manufacturers. Given that you're not going to like what
I have to say, but here's my ever so humble opinion:

If you're selling a product (like a ceiling fan) into a market where the
line voltages commonly go above 125V and are commonly dirty, and if you
make your ceiling fan so that it makes objectionable noises when these
commonly occurring conditions prevail, then you are making a poor
product and the best you deserve is to have your customers let you know
why they are abandoning you to other vendors.

If you're a manufacturer, ditto.

If you're an installer, you should be looking for a different
manufacturer to favor. Only if this problem exists across the whole
market, or if there's some compelling reason to avoid the fans that
don't hum at high voltages (like they're otherwise pieces of s**t or
something), should you try to fix the problem with bubble gum, spit, or
transformers in electrical boxes.

If _all_ the manufacturers out there are stupid, then there may be a
market opportunity here to make and sell these things. Of course, as
soon as you get really successful the ceiling fan manufacturers will
have lights go on in the dimness that dominates their brains and will
realize that there's money to be made in fans that don't hum, and
they'll start doing so and take away your business.

And it may be cheaper to just make your own damn fans.

Were it me and I did it, I'd sell out to the first ceiling fan
manufacturer that came sniffing around with enough cash to make it worth
my while -- because I would know that if I didn't, the next thing I'd
see would be "humless fans" on the market, and a big investment in
useless transformers sitting in unsellable piles in the
soon-to-be-not-mine business.

***************************
Thanks for your reply. Your faint hostility towards ceiling fan
manufacturers aside,

Faint?

you bring up some valid points and concerns.

It's not so much that I'm hostile against 'em -- it's that 125V is common
and getting more so, so if the fans really crap out at that point then a
bit of extra margin is a Good Thing. (And as you know, a problem that's
not complained about is a problem that's never addressed). If the noise
issues are really a small fraction of the problems then yes, a modular
solution makes sense.

You _may_ be able to explain the issues and ask the manufacturers if it's
possible to increase the design voltage by 5V or so -- but if the problem
really is rare then I suspect that the cost/benefit analysis won't play
out in your favor (and you may end up having problems with undervoltage,
or needing to increase the expense of the fan to make it work over a
wider range -- there's no free lunch).

As
a distributor with close ties to a couple manufacturers producing our
products, I may be defensive in my reading. My intent is not to profit
from the multitudes of crappy fans; my intent is a solution that
maintains customer satisfaction even where more power is desired. I
unfortunately have become the last stop in customer service escalation.

The typical amperage of a fan motor is 0.7A at 120V, max 1.25A for the
largest motors (permanent split capacitor induction motors). The
overvoltage hum only occurs on the larger, heavier motors that are the
more powerful air movers.

The overvoltages are not 'commonly' occurring conditions. That is why I
seek a modular solution, as they would only be needed in a fraction of a
percent of cases. These cases are invariably from electrician installed
fans, so I am not really looking for homeowner installed solution,
though the "fit into an outlet box" size certain would be more
convenient for the DIYer.

We have documented many causes of audible motor hum of the past few
decades, and most can be solved by simple solutions - tightening screws,
the use of a proper control (dimmers truncate the sine wave peaks), or
reinforcement/tightening of the installation site (extruded metal
beams/studs, split wood in beams/rafters, and torsion-box-built
ceilings, all transmit vibrations). Only the ones found to be
overvoltage/line noise issues are currently without solution, unless the
utility helps out.

I did a quick search on DigiKey for 5V to 6.3V transformers that would
handle currents close to your range. These should give you an idea of
the sizes you would really need, but just popping one of these in an
electrical box probably won't meet code (these are all intended to be
built into electronic equipment, not to be mounted in an electrical box
-- I'm sure NEMA would have something to say about using one of these).

Maybe find the manufacturer for one of the bigger transformers you're
looking at, and ask if they can make a 1.5A version?

http://tinyurl.com/d9z86gh

http://www.digikey.com/scripts/dksearch/dksus.dll?FV=fff4000c%2Cfff8012f%
2C19440006%2C19440033%2C19440061%2C19440065%2C1944008d%
2C1944008f&vendor=0&mnonly=0&newproducts=0&ptm=0&fid=0&quantity=0&PV1120=734&PV1120=1160&PV1120=732&PV1120=935&PV1120=994&PV1120=203&PV1120=95&PV1120=324&PV1120=198&PV1120=860&PV1120=402

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

 

[Cydrome Leader]

Jim Thompson <To-Email-Use-The-Envelope-Icon@on-my-web-site.com> wrote:

On Wed, 3 Apr 2013 17:40:23 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

ScottWW <spamtrap@dcorp.com> wrote:
"Jim Thompson" wrote in message
news:8qhml8hr2ib6g1olla6du6t3ubdv5doouo@4ax.com...

On Tue, 2 Apr 2013 16:47:02 -0400, "ScottWW" <spamtrap@dcorp.com
wrote:

Two occasional (electrical) causes of hum in electric motors (specifically
ceiling fans) are overvoltage and a noisy sine-wave.

If a US home is measured over 127VAC the local power utility will often
install a line conditioner. If a home is measured at 125VAC, in most cases
the power utility states that it is "within tolerances".

Tracking the source of line noise on 120VAC is often trial and error and
cannot always identify a single culprit. O'scopes are not commonly carried
by the installers. But I have documented a few overvoltage situations
where
the line noise was also present; and I suspect creating some of the
measured
overrvoltage.

I would like a device, that can reduce 125VAC voltage by 10% while
maintaining a smooth sine waveform. The last time I researched 120V
transformers for a 10% voltage reduction, they were too large (4"x 4" x 4")
for my purposes. Optimally I would like to this device to fit within a
"pancake box" outlet box, but even a 4" octagon outlet box.

Are there any new developments in small sized transformers capable of doing
this?
Does anybody have any ideas how else this could be accomplished?

Thanks!
Scott
Dunedin FL

There was recent thread on S.E.D...

"Mains wiring question: Sizing buck-boost transformer?"

Starting with Message-ID:
0001HW.CD7B40B60050CF9CB01029BF@news.eternal-september.org

that addresses your very problem.

...Jim Thompson
*******************
Thanks,
I am reading further...


You'll probably be breaking all sorts of codes, but an 8 volt doorbell
transformer might do what you want, if wired in buck mode. You'd want to
hide that in a box of some sort as there would be line voltage at the
screw terminals. Even if you wire the neutral to the low voltage side,
it's a nonstandard use and you don't want to confuse anybody. It might fit
in a deep two gang box.


I doubt that a doorbell transformer has sufficient KVA, but they're
generally box mountable and meet code, being metal enclosed and with a
stub that fits box knock-outs... at least here in AZ, no exposed screw
terminals.

...Jim Thompson

I've never seen a fully enclosed one around here as they're all screw terminals
staked onto some sort of fishpaper on the LV side, but you have so they must
exist.

I can't honestly say I have any idea how much current a ceiling fan draws, but if
it's just an amp or so, a wimpy doorbell transformer should be OK. Security
camera/alarm system/hvac transformers all seems to be rated too high in voltage,
but do seem to be beefier in power ratings.

 

[John Larkin]

On Wed, 3 Apr 2013 13:10:28 -0400, "ScottWW" <spamtrap@dcorp.com> wrote:

"John Larkin" wrote in message
news:fmkol855vrrjgo6tvge7eg2tbhngseicbl@4ax.com...

On Tue, 2 Apr 2013 16:47:02 -0400, "ScottWW" <spamtrap@dcorp.com> wrote:

Two occasional (electrical) causes of hum in electric motors (specifically
ceiling fans) are overvoltage and a noisy sine-wave.

A cheapish motor may saturate at high line voltage and create its own
harmonics.

A series inductor would be a good fix for both sorts of problems. It would
reduce the motor voltage and somewhat filter external harmonics. A series
cap
would help with the over-voltage but not externals.

Ceiling fans are great (we have no air conditioning in San Francisco and it
does
get warm once in a while) as long as they are quiet.

***************
Thank you for the reply. Jamie's reply to my post mentioned a Line Reactor
which appears to incorporate a series of inductors. I am reading more about
this now. I have suspected line noise is the true culprit and overvoltage
is a side-effect.

Core saturation in the motor has been discussed in the past with the
manufacturers (regarding heat rise), but the motors are designed to operate
at the median of saturation (at the normal voltage range) to limit heat
rise. I will bring this idea up again in regards to noise.

Scott

A lot of cheap motors and transformers are designed to the edge of saturation to
save copper and steel, and magnetizing current increases radically as line
voltage goes up. The current waveform gets very spikey, and saturation is
usually audible.

A ceiling fan might use one amp maybe, and if you want to drop 10 volts or so, a
single series inductor of roughly 30 to maybe 100 millihenries would do it.


--

John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

 

[George Herold]

On Apr 3, 1:10 pm, "ScottWW" <spamt...@dcorp.com> wrote:

"John Larkin"  wrote in message

news:fmkol855vrrjgo6tvge7eg2tbhngseicbl@4ax.com...

On Tue, 2 Apr 2013 16:47:02 -0400, "ScottWW" <spamt...@dcorp.com> wrote:
Two occasional (electrical) causes of hum in electric motors (specifically
ceiling fans) are overvoltage and a noisy sine-wave.

A cheapish motor may saturate at high line voltage and create its own
harmonics.

A series inductor would be a good fix for both sorts of problems. It would
reduce the motor voltage and somewhat filter external harmonics. A series
cap
would help with the over-voltage but not externals.

Ceiling fans are great (we have no air conditioning in San Francisco and it
does
get warm once in a while) as long as they are quiet.

***************
Thank you for the reply.  Jamie's reply to my post mentioned a Line Reactor
which appears to incorporate a series of inductors.  I am reading more about
this now.  I have suspected line noise is the true culprit and overvoltage
is a side-effect.

Core saturation in the motor has been discussed in the past with the
manufacturers (regarding heat rise), but the motors are designed to operate
at the median of saturation (at the normal voltage range) to limit heat
rise.  I will bring this idea up again in regards to noise.

Scott

That should be pretty easy to test. At least the over-voltage part.
Variac's typically go a bit ~10% overvoltage so you could see (or
hear) if the over voltage is the problem. If not .. then getting rid
of the line noise is a filtering issue. I would think there would be
some commercial pi or Tee low pass inline filters... but I don't have
any experience with AC power stuff.

George H.

 

[John Fields]

On Wed, 03 Apr 2013 18:41:41 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Wed, 3 Apr 2013 13:10:28 -0400, "ScottWW" <spamtrap@dcorp.com> wrote:

"John Larkin" wrote in message
news:fmkol855vrrjgo6tvge7eg2tbhngseicbl@4ax.com...

On Tue, 2 Apr 2013 16:47:02 -0400, "ScottWW" <spamtrap@dcorp.com> wrote:

Two occasional (electrical) causes of hum in electric motors (specifically
ceiling fans) are overvoltage and a noisy sine-wave.

A cheapish motor may saturate at high line voltage and create its own
harmonics.

A series inductor would be a good fix for both sorts of problems. It would
reduce the motor voltage and somewhat filter external harmonics. A series
cap
would help with the over-voltage but not externals.

Ceiling fans are great (we have no air conditioning in San Francisco and it
does
get warm once in a while) as long as they are quiet.

***************
Thank you for the reply. Jamie's reply to my post mentioned a Line Reactor
which appears to incorporate a series of inductors. I am reading more about
this now. I have suspected line noise is the true culprit and overvoltage
is a side-effect.

Core saturation in the motor has been discussed in the past with the
manufacturers (regarding heat rise), but the motors are designed to operate
at the median of saturation (at the normal voltage range) to limit heat
rise. I will bring this idea up again in regards to noise.

Scott

A lot of cheap motors and transformers are designed to the edge of saturation to
save copper and steel, and magnetizing current increases radically as line
voltage goes up. The current waveform gets very spikey, and saturation is
usually audible.

A ceiling fan might use one amp maybe, and if you want to drop 10 volts or so, a
single series inductor of roughly 30 to maybe 100 millihenries would do it.

---
Instead of giving a man a fish, why not teach a man how to fish?

--
JF

 

[Jamie]

George Herold wrote:

On Apr 3, 1:10 pm, "ScottWW" <spamt...@dcorp.com> wrote:

"John Larkin" wrote in message

news:fmkol855vrrjgo6tvge7eg2tbhngseicbl@4ax.com...

On Tue, 2 Apr 2013 16:47:02 -0400, "ScottWW" <spamt...@dcorp.com> wrote:

Two occasional (electrical) causes of hum in electric motors (specifically
ceiling fans) are overvoltage and a noisy sine-wave.

A cheapish motor may saturate at high line voltage and create its own
harmonics.

A series inductor would be a good fix for both sorts of problems. It would
reduce the motor voltage and somewhat filter external harmonics. A series
cap
would help with the over-voltage but not externals.

Ceiling fans are great (we have no air conditioning in San Francisco and it
does
get warm once in a while) as long as they are quiet.

***************
Thank you for the reply. Jamie's reply to my post mentioned a Line Reactor
which appears to incorporate a series of inductors. I am reading more about
this now. I have suspected line noise is the true culprit and overvoltage
is a side-effect.

Core saturation in the motor has been discussed in the past with the
manufacturers (regarding heat rise), but the motors are designed to operate
at the median of saturation (at the normal voltage range) to limit heat
rise. I will bring this idea up again in regards to noise.

Scott


That should be pretty easy to test. At least the over-voltage part.
Variac's typically go a bit ~10% overvoltage so you could see (or
hear) if the over voltage is the problem. If not .. then getting rid
of the line noise is a filtering issue. I would think there would be
some commercial pi or Tee low pass inline filters... but I don't have
any experience with AC power stuff.

George H.

A variac will hide noise and give you a false conclusion, Hence using
some sort of induction coupling, common mode style preferable.

Jamie

 

[John Larkin]

On Thu, 04 Apr 2013 18:31:34 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Wed, 03 Apr 2013 18:41:41 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Wed, 3 Apr 2013 13:10:28 -0400, "ScottWW" <spamtrap@dcorp.com> wrote:

"John Larkin" wrote in message
news:fmkol855vrrjgo6tvge7eg2tbhngseicbl@4ax.com...

On Tue, 2 Apr 2013 16:47:02 -0400, "ScottWW" <spamtrap@dcorp.com> wrote:

Two occasional (electrical) causes of hum in electric motors (specifically
ceiling fans) are overvoltage and a noisy sine-wave.

A cheapish motor may saturate at high line voltage and create its own
harmonics.

A series inductor would be a good fix for both sorts of problems. It would
reduce the motor voltage and somewhat filter external harmonics. A series
cap
would help with the over-voltage but not externals.

Ceiling fans are great (we have no air conditioning in San Francisco and it
does
get warm once in a while) as long as they are quiet.

***************
Thank you for the reply. Jamie's reply to my post mentioned a Line Reactor
which appears to incorporate a series of inductors. I am reading more about
this now. I have suspected line noise is the true culprit and overvoltage
is a side-effect.

Core saturation in the motor has been discussed in the past with the
manufacturers (regarding heat rise), but the motors are designed to operate
at the median of saturation (at the normal voltage range) to limit heat
rise. I will bring this idea up again in regards to noise.

Scott

A lot of cheap motors and transformers are designed to the edge of saturation to
save copper and steel, and magnetizing current increases radically as line
voltage goes up. The current waveform gets very spikey, and saturation is
usually audible.

A ceiling fan might use one amp maybe, and if you want to drop 10 volts or so, a
single series inductor of roughly 30 to maybe 100 millihenries would do it.

---
Instead of giving a man a fish, why not teach a man how to fish?

What do fish have to do with ceiling fans?


--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation