ACM3P 3-Phase AC Ammeters

[Winfield Hill]

Can a Murata / Datel ACM3P 3-Phase AC Ammeter,
complete with three current transformers, for $72,
be used with, e.g., a common single-phase 120-120
/ split 240 Vct household wiring, having both
balanced and unbalanced loads? A push-button
selects the "phase" you want to display. What
do they mean when they say 2-Phase AC current.


--
Thanks,
- Win

 

[Lasse Langwadt Christense]

lørdag den 18. april 2020 kl. 23.12.05 UTC+2 skrev Winfield Hill:

Can a Murata / Datel ACM3P 3-Phase AC Ammeter,
complete with three current transformers, for $72,
be used with, e.g., a common single-phase 120-120
/ split 240 Vct household wiring, having both
balanced and unbalanced loads? A push-button
selects the "phase" you want to display. What
do they mean when they say 2-Phase AC current.

maybe they just wrongly call split-phase 2-phase ?
Though in some places each house get two out of three phases,
which from the meters point of view would be the same as three phase
with no load on one of the phases

unless there is some timing that rely on 120degree I don't see why it
wouldn't work on split phase

 

[Ricky C]

On Saturday, April 18, 2020 at 5:34:19 PM UTC-4, Lasse Langwadt Christensen wrote:

lørdag den 18. april 2020 kl. 23.12.05 UTC+2 skrev Winfield Hill:
Can a Murata / Datel ACM3P 3-Phase AC Ammeter,
complete with three current transformers, for $72,
be used with, e.g., a common single-phase 120-120
/ split 240 Vct household wiring, having both
balanced and unbalanced loads? A push-button
selects the "phase" you want to display. What
do they mean when they say 2-Phase AC current.


maybe they just wrongly call split-phase 2-phase ?
Though in some places each house get two out of three phases,
which from the meters point of view would be the same as three phase
with no load on one of the phases

unless there is some timing that rely on 120degree I don't see why it
wouldn't work on split phase

Win is in the US and we use 120 volts as our commodity power for household appliances. You can't use two taps of the three phase power for that unless using a particular type of delta transformer that center taps a coil. But then it's still 240 volt split phase.

The point is each side of the 240 volt circuit must be 120 volts from neutral/ground because that's what we use for a return. True three phase doesn't need a neutral for power purposes.

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

 

[glen walpert]

On Sat, 18 Apr 2020 14:11:54 -0700, Winfield Hill wrote:

Can a Murata / Datel ACM3P 3-Phase AC Ammeter, complete with three
current transformers, for $72,
be used with, e.g., a common single-phase 120-120 / split 240 Vct
household wiring, having both balanced and unbalanced loads? A
push-button selects the "phase" you want to display.

Not familiar with that meter, but the description sounds like a single
phase ammeter with a push-button make before break selector switch -
unused CT's must be shorted and the meter connected before the short is
removed. This is the usual arrangement on 3-phase generator monitoring,
although I have only seen them with rotary selector switches. You could
put the third CT on the neutral of split single phase service to read all
three current carrying conductors if you wanted, that would allow you to
measure the excessive neutral current which occurs with haversine loads
which would otherwise be missed. Sounds like a deal if it works and the
range suits your load.

What do they mean
when they say 2-Phase AC current.

At one time 2-phase power distribution was used, with the two phases in
quadrature: https://en.wikipedia.org/wiki/Two-phase_electric_power
but this is long gone, and an open phase in 3-phase results in single
phase, so I am not sure where 2-phase power measurements would be useful
today.

 

[Lasse Langwadt Christense]

søndag den 19. april 2020 kl. 00.54.43 UTC+2 skrev Ricky C:

On Saturday, April 18, 2020 at 5:34:19 PM UTC-4, Lasse Langwadt Christensen wrote:
lørdag den 18. april 2020 kl. 23.12.05 UTC+2 skrev Winfield Hill:
Can a Murata / Datel ACM3P 3-Phase AC Ammeter,
complete with three current transformers, for $72,
be used with, e.g., a common single-phase 120-120
/ split 240 Vct household wiring, having both
balanced and unbalanced loads? A push-button
selects the "phase" you want to display. What
do they mean when they say 2-Phase AC current.


maybe they just wrongly call split-phase 2-phase ?
Though in some places each house get two out of three phases,
which from the meters point of view would be the same as three phase
with no load on one of the phases

unless there is some timing that rely on 120degree I don't see why it
wouldn't work on split phase

Win is in the US and we use 120 volts as our commodity power for household appliances. You can't use two taps of the three phase power for that unless using a particular type of delta transformer that center taps a coil. But then it's still 240 volt split phase.

The point is each side of the 240 volt circuit must be 120 volts from neutral/ground because that's what we use for a return. True three phase doesn't need a neutral for power purposes.

you can use two taps of the three phase power, it'll be 120V phase to neutral and 208V from phase to phase

I have three-phase like everyone else here, it would be rather inconvenient with out a neutral, having to run everything on 400V

 

[Ricky C]

On Saturday, April 18, 2020 at 8:01:48 PM UTC-4, Lasse Langwadt Christensen wrote:

søndag den 19. april 2020 kl. 00.54.43 UTC+2 skrev Ricky C:
On Saturday, April 18, 2020 at 5:34:19 PM UTC-4, Lasse Langwadt Christensen wrote:
lørdag den 18. april 2020 kl. 23.12.05 UTC+2 skrev Winfield Hill:
Can a Murata / Datel ACM3P 3-Phase AC Ammeter,
complete with three current transformers, for $72,
be used with, e.g., a common single-phase 120-120
/ split 240 Vct household wiring, having both
balanced and unbalanced loads? A push-button
selects the "phase" you want to display. What
do they mean when they say 2-Phase AC current.


maybe they just wrongly call split-phase 2-phase ?
Though in some places each house get two out of three phases,
which from the meters point of view would be the same as three phase
with no load on one of the phases

unless there is some timing that rely on 120degree I don't see why it
wouldn't work on split phase

Win is in the US and we use 120 volts as our commodity power for household appliances. You can't use two taps of the three phase power for that unless using a particular type of delta transformer that center taps a coil. But then it's still 240 volt split phase.

The point is each side of the 240 volt circuit must be 120 volts from neutral/ground because that's what we use for a return. True three phase doesn't need a neutral for power purposes.


you can use two taps of the three phase power, it'll be 120V phase to neutral and 208V from phase to phase

Yep and that's not what we use here. It has to be 240 volts from phase to phase so we can run our ovens an furnaces.

I suppose we could run them from 208 volts, but we don't because we have 240 volt split phase handy. If we did use 208 volts everything would provide 25% less power.

I see that when charging my car on level 2 chargers a lot. They are at commercial sites where they have 3 phase and they just give 208 volts to the connection rather than bother with 240 resulting in slower charge times.


> I have three-phase like everyone else here, it would be rather inconvenient with out a neutral, having to run everything on 400V

I'm talking about here where we use three phase as three phase, not as a distribution that you can pick lines off of for low voltage in the home. We have three phase on the power distribution, it's not very often brought down the street and hardly ever brought to a home. Pretty much commercial only.

--

Rick C.

+ Get 1,000 miles of free Supercharging
+ Tesla referral code - https://ts.la/richard11209

 

[Winfield Hill]

glen walpert wrote...

Not familiar with that meter, but the description sounds
like a single phase ammeter with a push-button make
before break selector switch - unused CT's must be shorted
and the meter connected before the short is removed.

This give me a chance to make a current-transformer rant.
IMHO all CTs should always have a connected load resistor.
And if that's not practical, they should have permanently
attached back-back diodes, to save the transformer (the
diodes won't conduct at normal FS load-resistor voltages).
There's no excuse for burning out a CT. At this point in
my CR4 rant, I posted pictures of huge destroyed, very
expensive high-current CTs (too easily found with Google).


--
Thanks,
- Win

 

[glen walpert]

On Sat, 18 Apr 2020 23:13:30 +0000, glen walpert wrote:

On Sat, 18 Apr 2020 14:11:54 -0700, Winfield Hill wrote:

Can a Murata / Datel ACM3P 3-Phase AC Ammeter, complete with three
current transformers, for $72,
be used with, e.g., a common single-phase 120-120 / split 240 Vct
household wiring, having both balanced and unbalanced loads? A
push-button selects the "phase" you want to display.

Not familiar with that meter, but the description sounds like a single
phase ammeter with a push-button make before break selector switch -
unused CT's must be shorted and the meter connected before the short is
removed. This is the usual arrangement on 3-phase generator monitoring,
although I have only seen them with rotary selector switches. You could
put the third CT on the neutral of split single phase service to read
all three current carrying conductors if you wanted, that would allow
you to measure the excessive neutral current which occurs with haversine
loads which would otherwise be missed.

Oops, the haversine induced excess neutral current is strictly a three
phase issue, not applicable to 120/240 single phase. I tend to think in
3-phase since 120/208 was used in every facility I have ever been paid to
work on/in. 120/240 single phase is only found in residential and very
small commercial facilities in the US.

Sounds like a deal if it works
and the range suits your load.

What do they mean when they say 2-Phase AC current.

At one time 2-phase power distribution was used, with the two phases in
quadrature: https://en.wikipedia.org/wiki/Two-phase_electric_power but
this is long gone, and an open phase in 3-phase results in single phase,
so I am not sure where 2-phase power measurements would be useful today.

 

[John S]

On 4/18/2020 7:32 PM, Ricky C wrote:

On Saturday, April 18, 2020 at 8:01:48 PM UTC-4, Lasse Langwadt Christensen wrote:
søndag den 19. april 2020 kl. 00.54.43 UTC+2 skrev Ricky C:
On Saturday, April 18, 2020 at 5:34:19 PM UTC-4, Lasse Langwadt Christensen wrote:
lørdag den 18. april 2020 kl. 23.12.05 UTC+2 skrev Winfield Hill:
Can a Murata / Datel ACM3P 3-Phase AC Ammeter,
complete with three current transformers, for $72,
be used with, e.g., a common single-phase 120-120
/ split 240 Vct household wiring, having both
balanced and unbalanced loads? A push-button
selects the "phase" you want to display. What
do they mean when they say 2-Phase AC current.


maybe they just wrongly call split-phase 2-phase ?
Though in some places each house get two out of three phases,
which from the meters point of view would be the same as three phase
with no load on one of the phases

unless there is some timing that rely on 120degree I don't see why it
wouldn't work on split phase

Win is in the US and we use 120 volts as our commodity power for household appliances. You can't use two taps of the three phase power for that unless using a particular type of delta transformer that center taps a coil. But then it's still 240 volt split phase.

The point is each side of the 240 volt circuit must be 120 volts from neutral/ground because that's what we use for a return. True three phase doesn't need a neutral for power purposes.


you can use two taps of the three phase power, it'll be 120V phase to neutral and 208V from phase to phase

Yep and that's not what we use here. It has to be 240 volts from phase to phase so we can run our ovens an furnaces.

I suppose we could run them from 208 volts, but we don't because we have 240 volt split phase handy. If we did use 208 volts everything would provide 25% less power.

I see that when charging my car on level 2 chargers a lot. They are at commercial sites where they have 3 phase and they just give 208 volts to the connection rather than bother with 240 resulting in slower charge times.


I have three-phase like everyone else here, it would be rather inconvenient with out a neutral, having to run everything on 400V

I'm talking about here where we use three phase as three phase, not as a distribution that you can pick lines off of for low voltage in the home. We have three phase on the power distribution, it's not very often brought down the street and hardly ever brought to a home. Pretty much commercial only.

What is split phase? Is that simply a single phase primary and
center-tapped secondary?

 

[Lasse Langwadt Christense]

søndag den 19. april 2020 kl. 15.28.11 UTC+2 skrev John S:

On 4/18/2020 7:32 PM, Ricky C wrote:
On Saturday, April 18, 2020 at 8:01:48 PM UTC-4, Lasse Langwadt Christensen wrote:
søndag den 19. april 2020 kl. 00.54.43 UTC+2 skrev Ricky C:
On Saturday, April 18, 2020 at 5:34:19 PM UTC-4, Lasse Langwadt Christensen wrote:
lørdag den 18. april 2020 kl. 23.12.05 UTC+2 skrev Winfield Hill:
Can a Murata / Datel ACM3P 3-Phase AC Ammeter,
complete with three current transformers, for $72,
be used with, e.g., a common single-phase 120-120
/ split 240 Vct household wiring, having both
balanced and unbalanced loads? A push-button
selects the "phase" you want to display. What
do they mean when they say 2-Phase AC current.


maybe they just wrongly call split-phase 2-phase ?
Though in some places each house get two out of three phases,
which from the meters point of view would be the same as three phase
with no load on one of the phases

unless there is some timing that rely on 120degree I don't see why it
wouldn't work on split phase

Win is in the US and we use 120 volts as our commodity power for household appliances. You can't use two taps of the three phase power for that unless using a particular type of delta transformer that center taps a coil. But then it's still 240 volt split phase.

The point is each side of the 240 volt circuit must be 120 volts from neutral/ground because that's what we use for a return. True three phase doesn't need a neutral for power purposes.


you can use two taps of the three phase power, it'll be 120V phase to neutral and 208V from phase to phase

Yep and that's not what we use here. It has to be 240 volts from phase to phase so we can run our ovens an furnaces.

I suppose we could run them from 208 volts, but we don't because we have 240 volt split phase handy. If we did use 208 volts everything would provide 25% less power.

I see that when charging my car on level 2 chargers a lot. They are at commercial sites where they have 3 phase and they just give 208 volts to the connection rather than bother with 240 resulting in slower charge times.


I have three-phase like everyone else here, it would be rather inconvenient with out a neutral, having to run everything on 400V

I'm talking about here where we use three phase as three phase, not as a distribution that you can pick lines off of for low voltage in the home. We have three phase on the power distribution, it's not very often brought down the street and hardly ever brought to a home. Pretty much commercial only.


What is split phase? Is that simply a single phase primary and
center-tapped secondary?

yes, https://en.wikipedia.org/wiki/Split-phase_electric_power

 

On Saturday, April 18, 2020 at 5:12:05 PM UTC-4, Winfield Hill wrote:

Can a Murata / Datel ACM3P 3-Phase AC Ammeter,
complete with three current transformers, for $72,
be used with, e.g., a common single-phase 120-120
/ split 240 Vct household wiring, having both
balanced and unbalanced loads? A push-button
selects the "phase" you want to display. What
do they mean when they say 2-Phase AC current.


--
Thanks,
- Win

It's just a dumb meter that independently measures the three CT inputs via A/D, which looks lke a 3:1 mux input. And quoting their own datasheet, phasing of the CT isn't even required.

"Current Transformer Phasing: Since the ACM3P only measures
amperes, transformer phasing is not required. ‘Phasing’ refers to the
direction of the current-carrying wire as it passes through the primary
hole of each of the three built-in current transformers."

The two phase jazz just means the meter is set up to display L1 and L2 channels, versus L1, L2 and L3 in 3-phase mode.

http://www.datelmeters.com/data/meters/acm3p-MC.pdf

 

[Winfield Hill]

bloggs.fredbloggs.fred@gmail.com wrote...

Winfield Hill wrote:

Can a Murata / Datel ACM3P 3-Phase AC Ammeter,=20
complete with three current transformers, for $72,
be used with, e.g., a common single-phase 120-120
/ split 240 Vct household wiring, having both=20
balanced and unbalanced loads? A push-button=20
selects the "phase" you want to display. What
do they mean when they say 2-Phase AC current.

It's just a dumb meter that independently measures the
three CT inputs via A/D, which looks like a 3:1 mux
input. And quoting their own datasheet, phasing of
the CT isn't even required.

"Current Transformer Phasing: Since the ACM3P only
measures amperes, transformer phasing is not required.
Phasing refers to the direction of the current-carrying
wire as it passes through the primary hole of each of
the three built-in current transformers."

The two phase jazz just means the meter is set up to
display L1 and L2 channels, versus L1, L2 and L3 in
3-phase mode.

http://www.datelmeters.com/data/meters/acm3p-MC.pdf

Thanks, Fred, it makes sense now.


--
Thanks,
- Win

 

[John S]

On 4/19/2020 9:09 AM, Lasse Langwadt Christensen wrote:

søndag den 19. april 2020 kl. 15.28.11 UTC+2 skrev John S:
On 4/18/2020 7:32 PM, Ricky C wrote:
On Saturday, April 18, 2020 at 8:01:48 PM UTC-4, Lasse Langwadt Christensen wrote:
søndag den 19. april 2020 kl. 00.54.43 UTC+2 skrev Ricky C:
On Saturday, April 18, 2020 at 5:34:19 PM UTC-4, Lasse Langwadt Christensen wrote:
lørdag den 18. april 2020 kl. 23.12.05 UTC+2 skrev Winfield Hill:
Can a Murata / Datel ACM3P 3-Phase AC Ammeter,
complete with three current transformers, for $72,
be used with, e.g., a common single-phase 120-120
/ split 240 Vct household wiring, having both
balanced and unbalanced loads? A push-button
selects the "phase" you want to display. What
do they mean when they say 2-Phase AC current.


maybe they just wrongly call split-phase 2-phase ?
Though in some places each house get two out of three phases,
which from the meters point of view would be the same as three phase
with no load on one of the phases

unless there is some timing that rely on 120degree I don't see why it
wouldn't work on split phase

Win is in the US and we use 120 volts as our commodity power for household appliances. You can't use two taps of the three phase power for that unless using a particular type of delta transformer that center taps a coil. But then it's still 240 volt split phase.

The point is each side of the 240 volt circuit must be 120 volts from neutral/ground because that's what we use for a return. True three phase doesn't need a neutral for power purposes.


you can use two taps of the three phase power, it'll be 120V phase to neutral and 208V from phase to phase

Yep and that's not what we use here. It has to be 240 volts from phase to phase so we can run our ovens an furnaces.

I suppose we could run them from 208 volts, but we don't because we have 240 volt split phase handy. If we did use 208 volts everything would provide 25% less power.

I see that when charging my car on level 2 chargers a lot. They are at commercial sites where they have 3 phase and they just give 208 volts to the connection rather than bother with 240 resulting in slower charge times.


I have three-phase like everyone else here, it would be rather inconvenient with out a neutral, having to run everything on 400V

I'm talking about here where we use three phase as three phase, not as a distribution that you can pick lines off of for low voltage in the home. We have three phase on the power distribution, it's not very often brought down the street and hardly ever brought to a home. Pretty much commercial only.


What is split phase? Is that simply a single phase primary and
center-tapped secondary?

yes, https://en.wikipedia.org/wiki/Split-phase_electric_power

The term split phase is not familiar to me. Thank you.

 

[glen walpert]

On Sun, 19 Apr 2020 06:22:04 -0700, Winfield Hill wrote:

glen walpert wrote...

Not familiar with that meter, but the description sounds like a single
phase ammeter with a push-button make before break selector switch -
unused CT's must be shorted and the meter connected before the short is
removed.

This give me a chance to make a current-transformer rant. IMHO all CTs
should always have a connected load resistor.
And if that's not practical, they should have permanently attached
back-back diodes, to save the transformer (the diodes won't conduct at
normal FS load-resistor voltages).
There's no excuse for burning out a CT. At this point in my CR4 rant,
I posted pictures of huge destroyed, very expensive high-current CTs
(too easily found with Google).

I am with you on that one, and even recall seeing an advertisement for
zener protected CTs a couple decades ago while working with protective
relaying. I don't know why it didn't catch on, but perhaps from lack of
demand from utilities, which have been using unprotected CTs for over 100
years. I just pulled out my copy of the first edition of "Principles of
Alternating Current Machinery" by Ralph Lawrence, published in 1916, and
it has 3-1/2 pages on current transformers. Included is a warning about
opening the secondary under load as this will cause core magnetization
and erroneous low output until the core is demagnetized. I once saw a
$2k CT replaced because no one knew to demagnetize it. Lawrence does not
mention the problem of insulation breakdown, and I think that this was
prevented in the scrapped $2k CT by a small arc gap built into the
integral shorting bar assembly, which is closed to service attached
wiring and instruments without disrupting power - a fairly common feature
in large CTs,

With large CT secondaries normally rated at 25 VA 5A they are not out of
spec below 5V RMS, 1v for small 5 VA CTs, with some overload/surge
capacity required, so I think back to back zeners are required. (The
internal burden approach does not work for using one CT with multiple
series wired meters and protective relays as is normal utility practice.)

There is nothing to stop us from bolting those missing zeners to the
terminals of our expensive CTs however.

Glen

 

[Ricky C]

On Monday, April 20, 2020 at 3:06:54 PM UTC-4, John S wrote:

On 4/19/2020 9:09 AM, Lasse Langwadt Christensen wrote:
søndag den 19. april 2020 kl. 15.28.11 UTC+2 skrev John S:
On 4/18/2020 7:32 PM, Ricky C wrote:
On Saturday, April 18, 2020 at 8:01:48 PM UTC-4, Lasse Langwadt Christensen wrote:
søndag den 19. april 2020 kl. 00.54.43 UTC+2 skrev Ricky C:
On Saturday, April 18, 2020 at 5:34:19 PM UTC-4, Lasse Langwadt Christensen wrote:
lørdag den 18. april 2020 kl. 23.12.05 UTC+2 skrev Winfield Hill:
Can a Murata / Datel ACM3P 3-Phase AC Ammeter,
complete with three current transformers, for $72,
be used with, e.g., a common single-phase 120-120
/ split 240 Vct household wiring, having both
balanced and unbalanced loads? A push-button
selects the "phase" you want to display. What
do they mean when they say 2-Phase AC current.


maybe they just wrongly call split-phase 2-phase ?
Though in some places each house get two out of three phases,
which from the meters point of view would be the same as three phase
with no load on one of the phases

unless there is some timing that rely on 120degree I don't see why it
wouldn't work on split phase

Win is in the US and we use 120 volts as our commodity power for household appliances. You can't use two taps of the three phase power for that unless using a particular type of delta transformer that center taps a coil. But then it's still 240 volt split phase.

The point is each side of the 240 volt circuit must be 120 volts from neutral/ground because that's what we use for a return. True three phase doesn't need a neutral for power purposes.


you can use two taps of the three phase power, it'll be 120V phase to neutral and 208V from phase to phase

Yep and that's not what we use here. It has to be 240 volts from phase to phase so we can run our ovens an furnaces.

I suppose we could run them from 208 volts, but we don't because we have 240 volt split phase handy. If we did use 208 volts everything would provide 25% less power.

I see that when charging my car on level 2 chargers a lot. They are at commercial sites where they have 3 phase and they just give 208 volts to the connection rather than bother with 240 resulting in slower charge times.


I have three-phase like everyone else here, it would be rather inconvenient with out a neutral, having to run everything on 400V

I'm talking about here where we use three phase as three phase, not as a distribution that you can pick lines off of for low voltage in the home.. We have three phase on the power distribution, it's not very often brought down the street and hardly ever brought to a home. Pretty much commercial only.


What is split phase? Is that simply a single phase primary and
center-tapped secondary?

yes, https://en.wikipedia.org/wiki/Split-phase_electric_power


The term split phase is not familiar to me. Thank you.

It's not familiar to most people in the US either. They want to call it two phase.

--

Rick C.

-- Get 1,000 miles of free Supercharging
-- Tesla referral code - https://ts.la/richard11209

 

[Robert Baer]

Ricky C wrote:

On Saturday, April 18, 2020 at 5:34:19 PM UTC-4, Lasse Langwadt Christensen wrote:
lørdag den 18. april 2020 kl. 23.12.05 UTC+2 skrev Winfield Hill:
Can a Murata / Datel ACM3P 3-Phase AC Ammeter,
complete with three current transformers, for $72,
be used with, e.g., a common single-phase 120-120
/ split 240 Vct household wiring, having both
balanced and unbalanced loads? A push-button
selects the "phase" you want to display. What
do they mean when they say 2-Phase AC current.


maybe they just wrongly call split-phase 2-phase ?
Though in some places each house get two out of three phases,
which from the meters point of view would be the same as three phase
with no load on one of the phases

unless there is some timing that rely on 120degree I don't see why it
wouldn't work on split phase

Win is in the US and we use 120 volts as our commodity power for household appliances. You can't use two taps of the three phase power for that unless using a particular type of delta transformer that center taps a coil. But then it's still 240 volt split phase.

The point is each side of the 240 volt circuit must be 120 volts from neutral/ground because that's what we use for a return. True three phase doesn't need a neutral for power purposes.

Why do you not use standard terminology: DELTA and WYE?

 

John S <Sophi.2@invalid.org> wrote in
news:r7s3b0$ukd$6@dont-email.me:

On 4/20/2020 5:29 PM, Ricky C wrote:
On Monday, April 20, 2020 at 3:06:54 PM UTC-4, John S wrote:
On 4/19/2020 9:09 AM, Lasse Langwadt Christensen wrote:
søndag den 19. april 2020 kl. 15.28.11 UTC+2 skrev John S:
On 4/18/2020 7:32 PM, Ricky C wrote:
On Saturday, April 18, 2020 at 8:01:48 PM UTC-4, Lasse
Langwadt Christensen wrote:
søndag den 19. april 2020 kl. 00.54.43 UTC+2 skrev Ricky C:
On Saturday, April 18, 2020 at 5:34:19 PM UTC-4, Lasse
Langwadt Christensen wrote:
lørdag den 18. april 2020 kl. 23.12.05 UTC+2 skrev
Winfield Hill:
Can a Murata / Datel ACM3P 3-Phase AC Ammeter,
complete with three current transformers, for $72,
be used with, e.g., a common single-phase 120-120
/ split 240 Vct household wiring, having both
balanced and unbalanced loads? A push-button
selects the "phase" you want to display. What
do they mean when they say 2-Phase AC current.


maybe they just wrongly call split-phase 2-phase ?
Though in some places each house get two out of three
phases, which from the meters point of view would be the
same as three phase with no load on one of the phases

unless there is some timing that rely on 120degree I don't
see why it wouldn't work on split phase

Win is in the US and we use 120 volts as our commodity
power for household appliances. You can't use two taps of
the three phase power for that unless using a particular
type of delta transformer that center taps a coil. But
then it's still 240 volt split phase.

The point is each side of the 240 volt circuit must be 120
volts from neutral/ground because that's what we use for a
return. True three phase doesn't need a neutral for power
purposes.


you can use two taps of the three phase power, it'll be 120V
phase to neutral and 208V from phase to phase

Yep and that's not what we use here. It has to be 240 volts
from phase to phase so we can run our ovens an furnaces.

I suppose we could run them from 208 volts, but we don't
because we have 240 volt split phase handy. If we did use
208 volts everything would provide 25% less power.

I see that when charging my car on level 2 chargers a lot.
They are at commercial sites where they have 3 phase and they
just give 208 volts to the connection rather than bother with
240 resulting in slower charge times.


I have three-phase like everyone else here, it would be
rather inconvenient with out a neutral, having to run
everything on 400V

I'm talking about here where we use three phase as three
phase, not as a distribution that you can pick lines off of
for low voltage in the home. We have three phase on the
power distribution, it's not very often brought down the
street and hardly ever brought to a home. Pretty much
commercial only.


What is split phase? Is that simply a single phase primary and
center-tapped secondary?

yes, https://en.wikipedia.org/wiki/Split-phase_electric_power


The term split phase is not familiar to me. Thank you.

It's not familiar to most people in the US either. They want to
call it two phase.


Too bad. AFAIK, there is no two phase power commercially supplied
in the US.

We get our 240 VAC from a pole transformer (or ground) off ONE
phase of a three pase HV distribution system. From that ONE phase,
there is a center tapped transformer which is 180 degrees out of
phase with each other, so each could be referred to as a phase, but
only within the US residential feed setting. So we get the full
single phase 240 volt feed from the pole, but we ALSO get the center
tap from that secondary, so that within the house, we can distribute
120 VAC branches, which are 'safer' from a human shock death risk
potential view. We feed the full 240 V to large consumption items
like electric dryers and our kitchen range.

So what gets 'supplied' is a center tapped supply of a tranformer
secondary of 240 VAC, which is essentially two 120 VAC feeds into the
home. One of the main features of this system is faulty return
handling, and at the pole, lightning strike management, as a hit on
an ungrounded floating feed could end up sraying lightning righ
inside your now ablaze home.

 

DecadentLinuxUserNumeroUno@decadence.org wrote in
news:r7s44j$1lps$1@gioia.aioe.org:

John S <Sophi.2@invalid.org> wrote in
news:r7s3b0$ukd$6@dont-email.me:

On 4/20/2020 5:29 PM, Ricky C wrote:
On Monday, April 20, 2020 at 3:06:54 PM UTC-4, John S wrote:
On 4/19/2020 9:09 AM, Lasse Langwadt Christensen wrote:
søndag den 19. april 2020 kl. 15.28.11 UTC+2 skrev John S:
On 4/18/2020 7:32 PM, Ricky C wrote:
On Saturday, April 18, 2020 at 8:01:48 PM UTC-4, Lasse
Langwadt Christensen wrote:
søndag den 19. april 2020 kl. 00.54.43 UTC+2 skrev Ricky
C:
On Saturday, April 18, 2020 at 5:34:19 PM UTC-4, Lasse
Langwadt Christensen wrote:
lørdag den 18. april 2020 kl. 23.12.05 UTC+2 skrev
Winfield Hill:
Can a Murata / Datel ACM3P 3-Phase AC Ammeter,
complete with three current transformers, for $72,
be used with, e.g., a common single-phase 120-120
/ split 240 Vct household wiring, having both
balanced and unbalanced loads? A push-button
selects the "phase" you want to display. What
do they mean when they say 2-Phase AC current.


maybe they just wrongly call split-phase 2-phase ?
Though in some places each house get two out of three
phases, which from the meters point of view would be the
same as three phase with no load on one of the phases

unless there is some timing that rely on 120degree I
don't see why it wouldn't work on split phase

Win is in the US and we use 120 volts as our commodity
power for household appliances. You can't use two taps of
the three phase power for that unless using a particular
type of delta transformer that center taps a coil. But
then it's still 240 volt split phase.

The point is each side of the 240 volt circuit must be 120
volts from neutral/ground because that's what we use for a
return. True three phase doesn't need a neutral for power
purposes.


you can use two taps of the three phase power, it'll be
120V phase to neutral and 208V from phase to phase

Yep and that's not what we use here. It has to be 240 volts
from phase to phase so we can run our ovens an furnaces.

I suppose we could run them from 208 volts, but we don't
because we have 240 volt split phase handy. If we did use
208 volts everything would provide 25% less power.

I see that when charging my car on level 2 chargers a lot.
They are at commercial sites where they have 3 phase and
they just give 208 volts to the connection rather than
bother with 240 resulting in slower charge times.


I have three-phase like everyone else here, it would be
rather inconvenient with out a neutral, having to run
everything on 400V

I'm talking about here where we use three phase as three
phase, not as a distribution that you can pick lines off of
for low voltage in the home. We have three phase on the
power distribution, it's not very often brought down the
street and hardly ever brought to a home. Pretty much
commercial only.


What is split phase? Is that simply a single phase primary
and center-tapped secondary?

yes, https://en.wikipedia.org/wiki/Split-phase_electric_power


The term split phase is not familiar to me. Thank you.

It's not familiar to most people in the US either. They want to
call it two phase.


Too bad. AFAIK, there is no two phase power commercially supplied
in the US.

We get our 240 VAC from a pole transformer (or ground) off ONE
phase of a three pase HV distribution system. From that ONE
phase, there is a center tapped transformer which is 180 degrees
out of phase with each other, so each could be referred to as a
phase, but only within the US residential feed setting. So we get
the full single phase 240 volt feed from the pole, but we ALSO get
the center tap from that secondary, so that within the house, we
can distribute 120 VAC branches, which are 'safer' from a human
shock death risk potential view. We feed the full 240 V to large
consumption items like electric dryers and our kitchen range.

So what gets 'supplied' is a center tapped supply of a
tranformer
secondary of 240 VAC, which is essentially two 120 VAC feeds into
the home. One of the main features of this system is faulty
return handling, and at the pole, lightning strike management, as
a hit on an ungrounded floating feed could end up sraying
lightning righ inside your now ablaze home.

fault return, not 'faulty'
spraying not sraying

 

[John S]

On 4/20/2020 5:29 PM, Ricky C wrote:

On Monday, April 20, 2020 at 3:06:54 PM UTC-4, John S wrote:
On 4/19/2020 9:09 AM, Lasse Langwadt Christensen wrote:
søndag den 19. april 2020 kl. 15.28.11 UTC+2 skrev John S:
On 4/18/2020 7:32 PM, Ricky C wrote:
On Saturday, April 18, 2020 at 8:01:48 PM UTC-4, Lasse Langwadt Christensen wrote:
søndag den 19. april 2020 kl. 00.54.43 UTC+2 skrev Ricky C:
On Saturday, April 18, 2020 at 5:34:19 PM UTC-4, Lasse Langwadt Christensen wrote:
lørdag den 18. april 2020 kl. 23.12.05 UTC+2 skrev Winfield Hill:
Can a Murata / Datel ACM3P 3-Phase AC Ammeter,
complete with three current transformers, for $72,
be used with, e.g., a common single-phase 120-120
/ split 240 Vct household wiring, having both
balanced and unbalanced loads? A push-button
selects the "phase" you want to display. What
do they mean when they say 2-Phase AC current.


maybe they just wrongly call split-phase 2-phase ?
Though in some places each house get two out of three phases,
which from the meters point of view would be the same as three phase
with no load on one of the phases

unless there is some timing that rely on 120degree I don't see why it
wouldn't work on split phase

Win is in the US and we use 120 volts as our commodity power for household appliances. You can't use two taps of the three phase power for that unless using a particular type of delta transformer that center taps a coil. But then it's still 240 volt split phase.

The point is each side of the 240 volt circuit must be 120 volts from neutral/ground because that's what we use for a return. True three phase doesn't need a neutral for power purposes.


you can use two taps of the three phase power, it'll be 120V phase to neutral and 208V from phase to phase

Yep and that's not what we use here. It has to be 240 volts from phase to phase so we can run our ovens an furnaces.

I suppose we could run them from 208 volts, but we don't because we have 240 volt split phase handy. If we did use 208 volts everything would provide 25% less power.

I see that when charging my car on level 2 chargers a lot. They are at commercial sites where they have 3 phase and they just give 208 volts to the connection rather than bother with 240 resulting in slower charge times.


I have three-phase like everyone else here, it would be rather inconvenient with out a neutral, having to run everything on 400V

I'm talking about here where we use three phase as three phase, not as a distribution that you can pick lines off of for low voltage in the home. We have three phase on the power distribution, it's not very often brought down the street and hardly ever brought to a home. Pretty much commercial only.


What is split phase? Is that simply a single phase primary and
center-tapped secondary?

yes, https://en.wikipedia.org/wiki/Split-phase_electric_power


The term split phase is not familiar to me. Thank you.

It's not familiar to most people in the US either. They want to call it two phase.

Too bad. AFAIK, there is no two phase power commercially supplied in the US.

 

[Winfield Hill]

DecadentLinuxUserNumeroUno@decadence.org wrote...

We get our 240 VAC from a pole transformer (or ground) off ONE
phase of a three pase HV distribution system. From that ONE phase,
there is a center tapped transformer which is 180 degrees out of
phase with each other, so each could be referred to as a phase, but
only within the US residential feed setting. So we get the full
single phase 240 volt feed from the pole, but we ALSO get the center
tap from that secondary, so that within the house, we can distribute
120 VAC branches, which are 'safer' from a human shock death risk
potential view. We feed the full 240 V to large consumption items
like electric dryers and our kitchen range.

So what gets 'supplied' is a center tapped supply of a tranformer
secondary of 240 VAC, which is essentially two 120 VAC feeds into the
home. One of the main features of this system is faulty return
handling, and at the pole, lightning strike management, as a hit on
an ungrounded floating feed could end up sraying lightning right
inside your now ablaze home.

We're supposed to have the center-tap neutral
wire solidly connected to a water-pipe ground
or similar. I've observed that for many older
installations, the two sides of the 240V come
in as two insulated wires, but the center tap
is connected to a steel cable supporting the
pole-to-house wiring. This saves adding a
third electrical wire. But the cable-clamp
connection is a weak spot, that can become
corroded and fail.


--
Thanks,
- Win