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440 volt three phase question



 
 
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  #21  
Old May 28th 10, 10:26 PM posted to alt.home.repair
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Posts: 1,941
Default 440 volt three phase question


" I've had the moment to work on 440 volt roof top heating and AC.

Once in a while, need some power to run a 120 volt device. Is it 120
volts from one leg to ground?

(Yeah, I could just check it. But I was on the roof yesterday, and not
sure how long until I get to another roof.)

How old is this roof top unit... Seriously 440 volts ? Are you sure
that it isn't 480 volts ?

Right; we should all tighten up our terminology, nominal voltage-wise.

It's 120, 240 and 480. *Not* 110, 220 and 440. (Not to mention all those
weird older numbers that were used, like 117 volts: WTF did that come
from???)


*I have found that the actual voltage varies by power company. One
company in NJ supplies 460/265 volts while another supplies 480/277. It
is quite possible that Stormin is dealing with 440 volts.


Don't doubt you at all; however, the *nominal* voltages are still
120/240/480. What you're describing are basically under-voltage
situations.



*LOL What about 208?

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  #22  
Old May 28th 10, 11:55 PM posted to alt.home.repair
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Posts: 2,913
Default 440 volt three phase question

On 5/28/2010 3:44 PM, harry wrote:
On May 28, 6:31�pm, Tom wrote:
On May 27, 5:22�pm, "Stormin Mormon"

wrote:
Oh, thank you. I didn't know.


--
Christopher A. Young
Learn more about Jesus
www.lds.org
.


wrote in message


...


�No, it's 220 more or less, to ground


It is entirely possible that the 440 volts is from a delta configured
transformer that is not ground referenced or is corner grounded.
Point is that one shouldn't assume that the transformer that is
supplying the current is Y configured.
--
Tom Horne


It's only possible to determine how a three phase transformer is
connected visually. Ie by checking the connections.


You can make a very reliable determination with just a meter and knowing
how 3 phase AC works.
  #23  
Old May 29th 10, 01:00 AM posted to alt.home.repair
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Posts: 10,563
Default 440 volt three phase question

More likely, I forgot the number, and typed it wong. I don't deal with
480/3 very often.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"John Grabowski" wrote in message
...


*I have found that the actual voltage varies by power company. One
company
in NJ supplies 460/265 volts while another supplies 480/277. It is
quite
possible that Stormin is dealing with 440 volts.



  #24  
Old May 29th 10, 06:03 AM posted to alt.home.repair
external usenet poster
 
Posts: 539
Default 440 volt three phase question

"Stormin Mormon" wrote in message
...
I've had the moment to work on 440 volt roof top heating and AC.

Once in a while, need some power to run a 120 volt device. Is it 120
volts from one leg to ground?

(Yeah, I could just check it. But I was on the roof yesterday, and not
sure how long until I get to another roof.)


No offense, Stormin, but the fact that you even have to ask such a Q means
you have no effing clue about electricity, and thus you proly should not be
fooling around with stuff that runs on electricity.

Proly missionary work is more your aptitude....

--
EA




--
Christopher A. Young
Learn more about Jesus
www.lds.org
.





  #25  
Old May 29th 10, 09:14 AM posted to alt.home.repair
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Posts: 9,216
Default 440 volt three phase question

On May 28, 10:55�pm, George wrote:
On 5/28/2010 3:44 PM, harry wrote:





On May 28, 6:31 pm, Tom �wrote:
On May 27, 5:22 pm, "Stormin Mormon"


�wrote:
Oh, thank you. I didn't know.


--
Christopher A. Young
Learn more about Jesus
www.lds.org
.


�wrote in message


...


No, it's 220 more or less, to ground


It is entirely possible that the 440 volts is from a delta configured
transformer that is not ground referenced or is corner grounded.
Point is that one shouldn't assume that the transformer that is
supplying the current is Y configured.
--
Tom Horne


It's only possible to determine how a three phase transformer is
connected �visually. �Ie by checking the connections.


You can make a very reliable determination with just a meter and knowing
how 3 phase AC works.- Hide quoted text -

- Show quoted text -


That is completely wrong.
  #26  
Old May 29th 10, 12:48 PM posted to alt.home.repair
external usenet poster
 
Posts: 10,563
Default 440 volt three phase question

So, tell us what's right.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"harry" wrote in message
...

You can make a very reliable determination with just a meter and
knowing
how 3 phase AC works.- Hide quoted text -

- Show quoted text -


That is completely wrong.


  #27  
Old May 29th 10, 01:32 PM posted to alt.home.repair
external usenet poster
 
Posts: 2,913
Default 440 volt three phase question

On 5/29/2010 3:14 AM, harry wrote:
On May 28, 10:55�pm, wrote:
On 5/28/2010 3:44 PM, harry wrote:





On May 28, 6:31 pm, Tom �wrote:
On May 27, 5:22 pm, "Stormin Mormon"


�wrote:
Oh, thank you. I didn't know.


--
Christopher A. Young
Learn more about Jesus
www.lds.org
.


�wrote in message


...


No, it's 220 more or less, to ground


It is entirely possible that the 440 volts is from a delta configured
transformer that is not ground referenced or is corner grounded.
Point is that one shouldn't assume that the transformer that is
supplying the current is Y configured.
--
Tom Horne


It's only possible to determine how a three phase transformer is
connected �visually. �Ie by checking the connections.


You can make a very reliable determination with just a meter and knowing
how 3 phase AC works.- Hide quoted text -

- Show quoted text -


That is completely wrong.


Really? So if we take the original question where the OP could have used
their meter and as an example observed 480 VAC between each phase leg
and 277 from each phase leg to neutral we couldn't declare with
confidence that the source transformers were connected in "Y" ?
  #28  
Old May 29th 10, 05:08 PM posted to alt.home.repair
external usenet poster
 
Posts: 9,216
Default 440 volt three phase question

On May 29, 12:32�pm, George wrote:
On 5/29/2010 3:14 AM, harry wrote:





On May 28, 10:55 pm, �wrote:
On 5/28/2010 3:44 PM, harry wrote:


On May 28, 6:31 pm, Tom � wrote:
On May 27, 5:22 pm, "Stormin Mormon"


� wrote:
Oh, thank you. I didn't know.


--
Christopher A. Young
Learn more about Jesus
www.lds.org
.


� wrote in message


...


No, it's 220 more or less, to ground


It is entirely possible that the 440 volts is from a delta configured
transformer that is not ground referenced or is corner grounded.
Point is that one shouldn't assume that the transformer that is
supplying the current is Y configured.
--
Tom Horne


It's only possible to determine how a three phase transformer is
connected visually. Ie by checking the connections.


You can make a very reliable determination with just a meter and knowing
how 3 phase AC works.- Hide quoted text -


- Show quoted text -


That is completely wrong.


Really? So if we take the original question where the OP could have used
their meter and as an example observed 480 VAC between each phase leg
and 277 from each phase leg to neutral we couldn't declare with
confidence that the source transformers were connected in "Y" ?- Hide quoted text -

- Show quoted text -


If you read my post, If there are just three line connections brought
out, no, you can't tell whether its "star" or "delta" connected.
  #29  
Old May 29th 10, 08:52 PM posted to alt.home.repair
external usenet poster
 
Posts: 2,913
Default 440 volt three phase question

On 5/29/2010 11:08 AM, harry wrote:
On May 29, 12:32�pm, wrote:
On 5/29/2010 3:14 AM, harry wrote:





On May 28, 10:55 pm, �wrote:
On 5/28/2010 3:44 PM, harry wrote:


On May 28, 6:31 pm, Tom � wrote:
On May 27, 5:22 pm, "Stormin Mormon"


� wrote:
Oh, thank you. I didn't know.


--
Christopher A. Young
Learn more about Jesus
www.lds.org
.


� wrote in message


...


No, it's 220 more or less, to ground


It is entirely possible that the 440 volts is from a delta configured
transformer that is not ground referenced or is corner grounded.
Point is that one shouldn't assume that the transformer that is
supplying the current is Y configured.
--
Tom Horne


It's only possible to determine how a three phase transformer is
connected visually. Ie by checking the connections.


You can make a very reliable determination with just a meter and knowing
how 3 phase AC works.- Hide quoted text -


- Show quoted text -


That is completely wrong.


Really? So if we take the original question where the OP could have used
their meter and as an example observed 480 VAC between each phase leg
and 277 from each phase leg to neutral we couldn't declare with
confidence that the source transformers were connected in "Y" ?- Hide quoted text -

- Show quoted text -


If you read my post, If there are just three line connections brought
out, no, you can't tell whether its "star" or "delta" connected.


I did. You didn't describe that limitation but you could still be a long
way from completely wrong with only a meter if you only had access to
the phase legs. Since a "Y" connection neutral is always bonded to
ground I could still get the same readings I described by placing one of
the meter probes on ground.
  #30  
Old May 29th 10, 09:41 PM posted to alt.home.repair
external usenet poster
 
Posts: 1,431
Default 440 volt three phase question

In article , George wrote:
On 5/29/2010 11:08 AM, harry wrote:
On May 29, 12:32�pm, wrote:
On 5/29/2010 3:14 AM, harry wrote:

On May 28, 10:55 pm, �wrote:
On 5/28/2010 3:44 PM, harry wrote:

On May 28, 6:31 pm, Tom � wrote:
On May 27, 5:22 pm, "Stormin Mormon"

� wrote:
Oh, thank you. I didn't know.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
.

� wrote in message

...

No, it's 220 more or less, to ground

It is entirely possible that the 440 volts is from a delta configured
transformer that is not ground referenced or is corner grounded.
Point is that one shouldn't assume that the transformer that is
supplying the current is Y configured.
--
Tom Horne

It's only possible to determine how a three phase transformer is
connected visually. Ie by checking the connections.

You can make a very reliable determination with just a meter and knowing
how 3 phase AC works.- Hide quoted text -

- Show quoted text -

That is completely wrong.

Really? So if we take the original question where the OP could have used
their meter and as an example observed 480 VAC between each phase leg
and 277 from each phase leg to neutral we couldn't declare with
confidence that the source transformers were connected in "Y" ?- Hide quoted text -

- Show quoted text -


If you read my post, If there are just three line connections brought
out, no, you can't tell whether its "star" or "delta" connected.


I did. You didn't describe that limitation but you could still be a long
way from completely wrong with only a meter if you only had access to
the phase legs. Since a "Y" connection neutral is always bonded to
ground I could still get the same readings I described by placing one of
the meter probes on ground.


It sounds easy enough for a 440V delta circuit to have all 3 legs
measure 277 volts from ground. One way for that to happen is if there is
significant and equal stray capacitance from each leg to ground. Another
is if someone connects a "Y" load to the circuit, and connects the load's
center point to ground.

--
- Don Klipstein )
 




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