Can a three phase motor wired in wye be rewired for delta?

MDR-Maker

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I have a surface grinder who's motor is wired in wye.

I need to install a three phase converter to make it run, both spindle motor and the hydraulic pump motor.

Reading through American Rotary's PAC are wired in delta and according to their tech folks I need a transformer(?) that will change the delta feed to wye. At about $700 I wanted to know if there is a less expensive route I can take.

The Doerr 1hp spindle motor has 9 leads and based on my research is wired in wye with leads 4,5,6 tied together.

Any help would be appreciated.

Thanks
 
Is this a dual voltage motor?
 
I thought 9 wire motors could be wired either way?
Mark
 
Is this a dual voltage motor?


To the best of knowledge it is.

Based on the wiring of the leads it's 220 volts. The motor plate shows it can be wired for 440.

I'm still trying to get more information on the motor. The model number is:67314GD801.
 
Correct me if I'm wrong but I think the delta connection is the lower voltage and the wye (or "star") is the higher-?
Can you post a pic of the motor plate?
Mark
ps I'm wrong it looks like the delta is the higher
 
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The spindle motor appears to be wired for low (240) volts. A nine wire motor with 4,5,6 tied together is the pointer there. It is "Wye" connected. To convert to delta, it would be necessary to physically enter the motor and access the (theoretical) 10, 11, 12 connections. They are connected internally and not easily accessable. And not so easily changed, even if you knew how to rewind a motor. Can be done(?) but then you have to deal with winding voltage ratings. One divided by the square root of three is your starting point there. Or the inverse of........

Then there is the pump(?) motor, already wound in delta. Likely a 12 wire motor, or a 6 wire fixed voltage motor. There wasn't much detail given for that one. Lacking that, I would have to ask:

What voltage did the machine run on before purchase? 240 or 480? In any case, there is no need to change the motor from one to the other. Just get the voltage right and go. Again, 240 or 480.....

The 3 phase conversion has two solutions. A rotary converter is nothing more than a 3 phase motor with a few capacitors and a kicker to start it. The electronic converter synthesizes a three phase output. It is not a pure sine wave but usable in motor(and other such) applications. Just don't run a transformer on it without derating it.

There should be no plausable need to switch a motor from wye to delta to make it work. Just hook it up for whichever voltage. If there is a passage in the converter instructions about a motor being wye or delta, I would take a long, hard look at the converter itself, not the motors. No, I don't have one. But I have worked with motors since 1969. And yet to let the majic smoke out.

Bill Hudson
[Edit] The connections I saw on the converter manufacturer page are relative only to how 120 volts are derived. As long as this device is used only for three phase loads, there is no concern. The assumption that you will be connected to a 120-240 single phase source, such as a shop sub-main, with multiple circuit breakers. If there are any 120 volt loads connected to the converter, just watch out for the "wild leg".
 
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Apparently this is a dual voltage motor and they do bring out all the necessary taps-
Waiting on a picture of the motor nameplate to see
Mark
 
The restriction regarding RPCs is when the motor Y is tied to neutral/ground. If the Y is not tied to neutral/ground, it should be a non-issue. You need to provide the motor plate/wiring or check the schematic, but. most motors do not have a Y star ground/neutral, T4-6 are just connect together. This is one reason why when measuring RPC voltages you look at leg to leg not leg to ground for balancing the voltages.

motor wiring.jpg
Per the blurb:
If a piece of three-phase equipment operates only on phase-to-phase voltages, it does not matter whether the power is configured as wye or as delta. If none of the circuits in the machine or the motor being operated derive a voltage by referencing neutral/ground, the machine does not know or care where ground/neutral is in reference to any of the phases. It only “sees” the relationship between the phases. It is evident that if you reference the three voltages of wye power and “erase” the connection to ground/neutral, you have a triangle, the same as in delta configured power. Only when equipment has single-phase 120V circuits that are derived from phase-to-neutral connections does it matter if the power is configured as wye or delta.

If the three-phase equipment has 120V phase-to-neutral circuits that cannot be isolated and connected to either leg 1 or leg 2, the output of the phase converter must be passed through a 240V delta to 120/208V wye isolation transformer. This transformer will establish ground and neutral at equal distance from all three legs and deliver the power in a wye configuration.
 
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Correct me if I'm wrong but I think the delta connection is the lower voltage and the wye (or "star") is the higher-?
Can you post a pic of the motor plate?
Mark
ps I'm wrong it looks like the delta is the higher
Correct me if I'm wrong but I think the delta connection is the lower voltage and the wye (or "star") is the higher-?
Can you post a pic of the motor plate?
Mark
ps I'm wrong it looks like the delta is the higher
Correct me if I'm wrong but I think the delta connection is the lower voltage and the wye (or "star") is the higher-?
Can you post a pic of the motor plate?
Mark
ps I'm wrong it looks like the delta is the higher
Apparently this is a dual voltage motor and they do bring out all the necessary taps-
Waiting on a picture of the motor nameplate to see
Mark


Mark, here is a picture of the motor plate.

photo (1).JPG
 
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