Delta vs Wye motor connections

[rattus]

When I said "the low voltage connection isn't quite so obvious" I wasn't implying that I didn't know how to do it. :roll: I was just saying "it isn't quite so obvious as the high voltage connection."

One way to look at the low voltage connection is that we are creating three open deltas.... not that we actually are, but going from my diagram, the LV connection would appear to be three open deltas.

Crossman, redraw your diagram and let the windings overlap about halfway but not connect. That should be obvious.

 

[crossman]

Okay, let me rephrase the whole thing.

It is obvious to me how the low voltage connection is made, just as it is obvious to the remainder of the astute observers on this forum. However, the low voltage connection is not quite so obvious to the average third year apprentice that I may come into contact with.

 

[coulter]

Crossman, redraw your diagram and let the windings overlap about halfway but not connect. That should be obvious.

Oh, you mean like the sketch I attached to post 7.

Crossman -
You really didn't need to rephrease. I think most of us got it that you knew.

carl

 

[crossman]

Carl, I appreciate your confidence!:smile:

 

[Luketrician]

here is a bunch of motor connection dwgs i ran across awhile back

http://www.usmotors.com/Connections/Connections.htm

enjoy

I just wanted to say thanks, for the link. Very informative!:smile:

 

[mull982]

No, if you have a 6-lead 480v motor, you have the option of 240v or 480v, but it will remain wye or delta. A 9-lead motor is actually a 12-lead motor with one connection point inaccessible.

To switch a motor between wye and delta, you need all of the winding ends individually accessible, which means it will be a 6-lead, single-voltage motor, or a 12-lead, dual-voltage motor.

Let me summarize what I think I understand

1) If I have a 3 lead motor I do not care weather it is wired for wye or delta.
For instance if I have a 480V motor then I dont care how its wired, and if
its wired in a wye configuration then although the voltage across the coils
will only be 58% the motor manufacturer has already accounted for this
for the motors proper operation.

2) If I have a 6-lead dual voltage motor, such as 480/240 for example then it
will be either delta for both voltages, or wye for both voltages and is not
meant to be swapped between delta and wye for different voltages.

3) If I have a 6-lead single voltage motor such as a 480V motor then there is
an option weather to wire it for wye or delta. There is also an option for
wiring this type of motor for a wye-start, delt-run configuration. You have
to keep in mind however that in the wye configuration there will only be
58% of the voltage across the coils. What is a case where I would want
to run a motor in the wye configuration with a particular system voltage
avaliable?

 

[LarryFine]

Unless, I'm missing something, I'd say you've got it.

 

[crossman]

Would someone be so kind as to draw the windings of a six-lead dual-voltage (as in 480/240) 3 phase motor? I am missing how it can be done.

 

[mivey]

Would someone be so kind as to draw the windings of a six-lead dual-voltage (as in 480/240) 3 phase motor? I am missing how it can be done.

You think they meant to say 480/277 wye/delta?

 

[Smart $]

Would someone be so kind as to draw the windings of a six-lead dual-voltage (as in 480/240) 3 phase motor? I am missing how it can be done.

Can't be done with a voltage ratio at 2:1, but at 1.732:1 it can be!

For example:

http://www.usmotors.com/Products/ProFacts/1-105ydelta6.htm
http://apps.motorboss.com/connections/438252.pdf​

 

[Jraef]

Would someone be so kind as to draw the windings of a six-lead dual-voltage (as in 480/240) 3 phase motor? I am missing how it can be done.

Did you see someone imply that this existed? I didn't see that.


Edit:
Ah, I see it now...

...
2) If I have a 6-lead dual voltage motor, such as 480/240 for example then it
will be either delta for both voltages, or wye for both voltages and is not
meant to be swapped between delta and wye for different voltages.

There it is.
So mull982, this is incorrect. You would NOT have a 480/240V motor with only 6 leads. It would be EITHER 480V or 240V, not both, or it would be 480/240V, but at least 9 leads.

3) I... What is a case where I would want to run a motor in the wye configuration with a particular system voltage
avaliable?

None that I can think of, as a good practice anyway. But I have seen a couple of people do it when they need a lot less power now, but install a much larger motor for future growth. I never recommend it because the torque is so low that more of the energy consumed is going to just spinning the motor mass, meaning that the power-to-useful-work ratio is lower. But sometimes budgets are available now and may not be later, so they go ahead with it.