rotary inverters

Feb 24, 2005

From http://www.eere.energy.gov/consumerinfo/factsheets/bb8.html

"Rotary Inverter:
In a rotary inverter, DC electricity input powers a DC motor that turns
an AC generator. Rotary inverters are reliable and produce a pure
sine-wave output. These inverters have automatic load demand: they
begin operation once a load is activated, and shut down when the load
is removed. Disadvantages of a rotary inverter are lack of frequency
control, low surge capability (50% above maximum rating) and lower
efficiency (50% to 80%). Rotary inverters are not as common as
electronic inverters."

Would rotary inverters be cheaper than true-sine-wave electronic
inverters?

Anyone know who sells rotary inverters, or the parts to make one
(110/220VAC, 60 hz output)?

Thanks in advance,

Mike Darrett

John Fields · Feb 24, 2005

On 24 Feb 2005 14:48:00 -0800, mike-nospam@darrettenterprises.com
wrote:

From http://www.eere.energy.gov/consumerinfo/factsheets/bb8.html

"Rotary Inverter:
In a rotary inverter, DC electricity input powers a DC motor that turns
an AC generator. Rotary inverters are reliable and produce a pure
sine-wave output. These inverters have automatic load demand: they
begin operation once a load is activated, and shut down when the load
is removed. Disadvantages of a rotary inverter are lack of frequency
control, low surge capability (50% above maximum rating) and lower
efficiency (50% to 80%). Rotary inverters are not as common as
electronic inverters."

Would rotary inverters be cheaper than true-sine-wave electronic
inverters?

Anyone know who sells rotary inverters, or the parts to make one
(110/220VAC, 60 hz output)?

---
http://www.google.com/search?hl=en&q=rotary+inverter&spell=1

--
John Fields

Feb 24, 2005

Whoa... they run about $600 or so for the small one (500W).

Guess it might be worthwhile to try and make one from scratch after
all...

Mike

Pooh Bear · Feb 25, 2005

mike-nospam@darrettenterprises.com wrote:

Whoa... they run about $600 or so for the small one (500W).

Guess it might be worthwhile to try and make one from scratch after
all...

Hmmm.......

A friend approached me about designing sinewave inverters to run off bus
/ coach batteries to drive video entertainment systems about 20 yrs ago.
He couldn't come up with a spec so I told him to get lost.

Surely someone must have done this economically by now ?

If you mentioned exactly what equipment you want to use from what kind
of source - at what power level - we might be able to help you better.

Graham

James Meyer · Feb 25, 2005

On Thu, 24 Feb 2005 19:03:40 -0700, Jim Thompson <thegreatone@example.com>
wroth:

More fundamentally, I've considered rounding up an old M-G (as in
gasoline motor) set as the ultimate in UPS ;-)

...Jim Thompson

The "U" in UPS stands for uninterruptable. Do you plan to have the MG
set running continually? Or have you come up with a way to get the motor
started and up to speed in a fraction of a second?

Otherwise it would only be the ultimate in SPS or Standby Power Supply.

Jim "The other one" Meyer

Jim Thompson · Feb 25, 2005

On Fri, 25 Feb 2005 13:04:29 GMT, James Meyer <jmeyer@nowhere.net>
wrote:

On Thu, 24 Feb 2005 19:03:40 -0700, Jim Thompson <thegreatone@example.com
wroth:

More fundamentally, I've considered rounding up an old M-G (as in
gasoline motor) set as the ultimate in UPS ;-)

...Jim Thompson

The "U" in UPS stands for uninterruptable. Do you plan to have the MG
set running continually? Or have you come up with a way to get the motor
started and up to speed in a fraction of a second?

Otherwise it would only be the ultimate in SPS or Standby Power Supply.

Jim "The other one" Meyer

UPS + MG set

In the past, Arizona has been noted for multi-hour outages.

At this "new" house I hadn't had a single outage for 11 years UNTIL
last week when we were down for an hour.

SInce I often have multi-hour PSpice simulations in progress a typical
UPS can't hold up that long, thus the MG set idea.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice

480)460-2350 | |
| E-mail Address at Website Fax

boB · Feb 26, 2005

On Fri, 25 Feb 2005 02:02:12 +0000, Pooh Bear
<rabbitsfriendsandrelations@hotmail.com> wrote:

mike-nospam@darrettenterprises.com wrote:

From http://www.eere.energy.gov/consumerinfo/factsheets/bb8.html

"Rotary Inverter:
In a rotary inverter, DC electricity input powers a DC motor that turns
an AC generator. Rotary inverters are reliable and produce a pure
sine-wave output. These inverters have automatic load demand: they
begin operation once a load is activated, and shut down when the load
is removed. Disadvantages of a rotary inverter are lack of frequency
control, low surge capability (50% above maximum rating) and lower
efficiency (50% to 80%). Rotary inverters are not as common as
electronic inverters."

Would rotary inverters be cheaper than true-sine-wave electronic
inverters?

Anyone know who sells rotary inverters, or the parts to make one
(110/220VAC, 60 hz output)?

Military surplus stores maybe ? They used to use these things a lot.

Graham

It's called a dynamotor. Some of them on E-bay. I used to see them
at ham-fests all the time. getting kind of rare. I think there were
a lot of them from military surplus places.

For sine wave inverters that kind of look like dynamotors, go to
www.outbackpower.com

boB

Zak · Feb 26, 2005

Guy Macon wrote:

I haven't worked with rotary inverters, but I have worked with
rotary converters; a 60Hz motor driving a gear driving a 50 Hz.
generator. It was 12 feet high and 20 feet long, and was the
lowest-cost way to get a *lot* of true simewave 50 Hz. power.
I suspect that the economics are the same with rotary onverters.

If the goal is DC to AC or teh other way around a single armature can be
used, with brushes on one side (the DC side) and slip rings on teh otehr
side (the AC side).

This saves a lot of iron I think.

Thomas

Jim Thompson · Feb 27, 2005

On Sun, 27 Feb 2005 09:07:36 -0700, Jim Thompson
<thegreatone@example.com> wrote:

On Sun, 27 Feb 2005 10:53:16 -0500, Mark Jones <abuse@127.0.0.1
wrote:

[snip]

Do you watch "This Old House" at all? The barn they're renovating now has a
nice gas-powered generator. Perhaps something like that would work, combined
with a small backup battery array and inverter. Tricky part would be
load-switching from battery/inverter to generator. Prolly easiest to buy a
premade unit for the job?

I'll have to see if it's playing here in Phoenix.

[snip]

480)460-2350 | |
| E-mail Address at Website Fax

Terry Given · Feb 27, 2005

Jim Thompson wrote:

On Sun, 27 Feb 2005 10:53:16 -0500, Mark Jones <abuse@127.0.0.1
wrote:

Jim Thompson wrote:

On Fri, 25 Feb 2005 13:04:29 GMT, James Meyer <jmeyer@nowhere.net
wrote:

On Thu, 24 Feb 2005 19:03:40 -0700, Jim Thompson <thegreatone@example.com
wroth:

More fundamentally, I've considered rounding up an old M-G (as in
gasoline motor) set as the ultimate in UPS ;-)

...Jim Thompson

The "U" in UPS stands for uninterruptable. Do you plan to have the MG
set running continually? Or have you come up with a way to get the motor
started and up to speed in a fraction of a second?

Otherwise it would only be the ultimate in SPS or Standby Power Supply.

Jim "The other one" Meyer

UPS + MG set

In the past, Arizona has been noted for multi-hour outages.

At this "new" house I hadn't had a single outage for 11 years UNTIL
last week when we were down for an hour.

SInce I often have multi-hour PSpice simulations in progress a typical
UPS can't hold up that long, thus the MG set idea.

...Jim Thompson

Do you watch "This Old House" at all? The barn they're renovating now has a
nice gas-powered generator. Perhaps something like that would work, combined
with a small backup battery array and inverter. Tricky part would be
load-switching from battery/inverter to generator. Prolly easiest to buy a
premade unit for the job?

I'll have to see if it's playing here in Phoenix.

PBS has gone seriously down hill, playing mostly politically-correct
BS, so I let my support membership lapse after more than thirty years
as a "gold" member.

I don't think I've turned on that channel at all in the past year.

Switching is downright trivial with a UPS...

Lose AC for more than 15 minutes, drop AC connection to UPS, start MG
set, connect MG set to UPS. Synchronization isn't an issue at all.

Biggest problem would possibly be gasoline degradation while it sits.
Might be better to go with a natural gas unit, or, in my case of an
all-electric utility situation, a propane unit.

...Jim Thompson

When I used to live in MA I was designing UPS systems. I forget now what
the name of the electrickery authority who throws money at PQ problems,
but the numbers we had were:

99.9% of all outages in US are sub 3 seconds

those that arent tend to be > 15 minutes.

our flywheel based system provided 11.5s of go-juice - enough to ride
out the 3s outage then black-start an MG set if the power still hadnt
cme back on. IIRC the 3s is tied in with the switching time of
auto-reclose breakers. If you are on the branch with the fault, the ARBs
will disconnect you, hence the > 15 minutes - actually however long it
took to fix the fault. If you are on another branch, your supply will
come right when the faulty branch is isolated.

Cheers
Terry

Rich Grise · Feb 28, 2005

On Mon, 28 Feb 2005 11:27:19 +1300, Terry Given wrote:

99.9% of all outages in US are sub 3 seconds

those that arent tend to be > 15 minutes.

our flywheel based system provided 11.5s of go-juice - enough to ride
out the 3s outage then black-start an MG set if the power still hadnt
cme back on. IIRC the 3s is tied in with the switching time of
auto-reclose breakers. If you are on the branch with the fault, the ARBs
will disconnect you, hence the > 15 minutes - actually however long it
took to fix the fault. If you are on another branch, your supply will
come right when the faulty branch is isolated.

Just the other day, they plugged in a couple of grinders on the same
line that my office is on - with my two computers and the company's
server - and in quick succession I got two HUGE glitches that shut down
all of the computers. The lights came on, but the computers stayed off.
Then, just as I was turning the computers on I got another HUGE glitch,
and I went and told them to plug the grinders in somewhere else. Then,
I came back into the office and two out of three of the computers
wouldn't turn on by the front panel button. I had to reach around and
turn off the mains switch on both of them to recycle the shutdown circuit.
I was a little nervous there for a minute or two!

Cheers!
Rich

Michael A. Terrell · Feb 28, 2005

Terry Given wrote:

When I used to live in MA I was designing UPS systems. I forget now what
the name of the electrickery authority who throws money at PQ problems,
but the numbers we had were:

99.9% of all outages in US are sub 3 seconds

those that arent tend to be > 15 minutes.

our flywheel based system provided 11.5s of go-juice - enough to ride
out the 3s outage then black-start an MG set if the power still hadnt
cme back on. IIRC the 3s is tied in with the switching time of
auto-reclose breakers. If you are on the branch with the fault, the ARBs
will disconnect you, hence the > 15 minutes - actually however long it
took to fix the fault. If you are on another branch, your supply will
come right when the faulty branch is isolated.

Cheers
Terry

Around here if its more than a few seconds its usually several hours
because its a blown fuse in an outdated 7200 volt distribution system.
A 60 amp fuse feeding about 40 homes. It was built for 60 amp service
per home 41 years ago. Most homes now have 200 amp service, the rest
are 150 amp. Almost every home has an electric stove and central air. A
few have electric heat, as well. The numbers don't add up on hot days,
or the few really cold days when a heat pump won't keep up and the heat
strips kick in.
--
Beware of those who post from srvinet.com!

Michael A. Terrell
Central Florida

Jim Thompson · Feb 27, 2005

On Sun, 27 Feb 2005 10:53:16 -0500, Mark Jones <abuse@127.0.0.1>
wrote:

Jim Thompson wrote:
On Fri, 25 Feb 2005 13:04:29 GMT, James Meyer <jmeyer@nowhere.net
wrote:

On Thu, 24 Feb 2005 19:03:40 -0700, Jim Thompson <thegreatone@example.com
wroth:

More fundamentally, I've considered rounding up an old M-G (as in
gasoline motor) set as the ultimate in UPS ;-)

...Jim Thompson

The "U" in UPS stands for uninterruptable. Do you plan to have the MG
set running continually? Or have you come up with a way to get the motor
started and up to speed in a fraction of a second?

Otherwise it would only be the ultimate in SPS or Standby Power Supply.

Jim "The other one" Meyer

UPS + MG set

In the past, Arizona has been noted for multi-hour outages.

At this "new" house I hadn't had a single outage for 11 years UNTIL
last week when we were down for an hour.

SInce I often have multi-hour PSpice simulations in progress a typical
UPS can't hold up that long, thus the MG set idea.

...Jim Thompson

Do you watch "This Old House" at all? The barn they're renovating now has a
nice gas-powered generator. Perhaps something like that would work, combined
with a small backup battery array and inverter. Tricky part would be
load-switching from battery/inverter to generator. Prolly easiest to buy a
premade unit for the job?

I'll have to see if it's playing here in Phoenix.

PBS has gone seriously down hill, playing mostly politically-correct
BS, so I let my support membership lapse after more than thirty years
as a "gold" member.

I don't think I've turned on that channel at all in the past year.

Switching is downright trivial with a UPS...

Lose AC for more than 15 minutes, drop AC connection to UPS, start MG
set, connect MG set to UPS. Synchronization isn't an issue at all.

Biggest problem would possibly be gasoline degradation while it sits.
Might be better to go with a natural gas unit, or, in my case of an
all-electric utility situation, a propane unit.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice

480)460-2350 | |
| E-mail Address at Website Fax

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