three phase to single motor

[GMc]

I dont think its a good idea to ever assume anything

Thats all we can do when the OP didn't give the detail some others think they need.

The only flavor of three phase I am really sure about is 208 Wye that it does not have a wild leg. It is possible that the variety of three phase he is dealing with has a wild leg and if so, don't just pick any two legs to connect the motor.

Even if it was a Delta with a center tap, any 2 phases would still give you your 240v single phase. What your referring to is if you went from the grounded conductor (neutral) to the high leg you would have 208v.

Refer to post #10 we are only wasting time without any more details.

Wasting time only because I answered the OP's question in post #3.

Also, I don't believe it's a waste of time when some might be learning from the post's

 

[shawn_75]

Even if it was a Delta with a center tap, any 2 phases would still give you your 240v single phase. What your referring to is if you went from the grounded conductor (neutral) to the high leg you would have 208v.

Yes, but the motor is also capable of 115V which is where this would be a valid point to consider.

 

[TurpoUrpo]

Thats all we can do when the OP didn't give the detail some others think they need.

I must be missing something. Why one is not allowed to ask more detail?

...
Wasting time only because I answered the OP's question in post #3.

Also, I don't believe it's a waste of time when some might be learning from the post's

Then why not ask more detail and construct more informing thread. Waste of time is to say one cant ask more detail. And ur post atleast was not so "teaching" just answering the question and not providing any "whys" is not really teaching anybody. You did not even consider if the system is not same you think it is.

Yes, but the motor is also capable of 115V which is where this would be a valid point to consider.

There is no reason to consider 115V if 240V is readily available.

 

[JeffKiper]

Wasting time only because I answered the OP's question in post #3.

Also, I don't believe it's a waste of time when some might be learning from the post's

I think you and I are midding something. I said it was a waste of time because we are all assuming that the system he has is like we think of first. I have learned from some great guys around this site and well as around the different shop I have been in to NEVER ASSUME.

Just a question what type of system did you assume the OP had when he said 3 phase? My gut was Wye but for the last 3 months I have bee working in a shop that has ungrounded Delta. I just quoted a machine shop that is 3 phase center leg ground shop.

 

[GMc]

I think you and I are midding something. I said it was a waste of time because we are all assuming that the system he has is like we think of first. I have learned from some great guys around this site and well as around the different shop I have been in to NEVER ASSUME.

Just a question what type of system did you assume the OP had when he said 3 phase? My gut was Wye but for the last 3 months I have bee working in a shop that has ungrounded Delta. I just quoted a machine shop that is 3 phase center leg ground shop.

Lets start over..

Do you agree when he said 240v 3 phase that it would have to be delta?

 

[TurpoUrpo]

Why it would have to be delta? That is the point, you also need to provide "whys" on your opinion.

 

[GMc]

Why it would have to be delta? That is the point, you also need to provide "whys" on your opinion.

Turpo,

Sorry I didn't respond with the "whys" but the OP was fine with my answer and nobody else asked "why" until we got on the offensive. Sorry if I offended anyone

If you had 3 240v transformers wired in a Wye configuration what would the voltage be Phase to Phase?

 

[shawn_75]

There is no reason to consider 115V if 240V is readily available.

Yes, but what if the OP was intending to use a single pole switch? Based on the OPs original post I'd venture a guess that he may not know about the wild leg.

 

[JesperMP]

Hotrod, post a picture of the motor nameplate.

 

[pompey cabilan]

you could run a 3 phase motor from a single phase supply. in order to explain briefly we take the following assumptions:
mark the three leads from the motor as A, B, C
Leads A & B will your line from source
Lead C is free, so install a starting capacitor. This capacitor must be disconnected when the motor gets up to speed.
Install a running capacitor between lead C to A. This capacitor will stay on line as long as the motor is running.

You must design the control circuit to disconnect the running capacitor. I use a timer to disconnect the starting capacitor timed to about one second

 

[DickDV]

Mercy! There is a bunch of nonsense in this post. First, the OP said he had 240V three phase. Now, it matters nothing that it is floating delta, corner ground delta, mid-phase ground delta, floating wye, grounded wye, resistance grounded wye. All of these are still 240V three phase and if the motor is connected across any two phases, it will see only single phase 240V and run fine. No, there is no crazy leg as far as the phases are concerned. There might be with some of the above configured sources a crazy or stinger or high leg to ground but that is not how the motor is to be wired.

Now, if the OP has 208 three phase---but no, he said he had 240V three phase so that is the end of that!

If some would like to start a thread on power sources and the various configurations, then let's do that. I'll help if I can.

 

[Stationmaster]

Mercy! There is a bunch of nonsense in this post. First, the OP said he had 240V three phase. Now, it matters nothing that it is floating delta, corner ground delta, mid-phase ground delta, floating wye, grounded wye, resistance grounded wye. All of these are still 240V three phase and if the motor is connected across any two phases, it will see only single phase 240V and run fine. No, there is no crazy leg as far as the phases are concerned. There might be with some of the above configured sources a crazy or stinger or high leg to ground but that is not how the motor is to be wired.

Now, if the OP has 208 three phase---but no, he said he had 240V three phase so that is the end of that!

If some would like to start a thread on power sources and the various configurations, then let's do that. I'll help if I can.

Once again, the clear voice in the storm....

 

[brucechase]

Actually, I thought the clear voice was in post #3.