Switching Ingersoll Rand 15hp compressor from 240D to 208Y Help

[DrSparks]

So I'm looking at the nameplate here and it says under the configuraton "Y - START ONLY" can anyone tell me what that means? Do I need a motor starter for this unit? I took out their old 240 delta service and put in a 480/277 and a 150kva 208Y transformer. The owner didn't want to have Ingersoll put in a new 480 motor so he asked me to reconnect this one to the transformer. Help anyone?

 

[GoldDigger]

Without any comparable labels or the full motor documentation, I can see two interpretations which are very different.
It could mean that you must always use a delta-wye starter.
But I think I is much more likely to mean that the voltage and other information on the label applies to the delta connection only, and that the wye connection information is shown for optional use for starting only and must not be used for run, even if you supply a different voltage.

 

[Jraef]

So I'm looking at the nameplate here and it says under the configuraton "Y - START ONLY" can anyone tell me what that means? Do I need a motor starter for this unit? I took out their old 240 delta service and put in a 480/277 and a 150kva 208Y transformer. The owner didn't want to have Ingersoll put in a new 480 motor so he asked me to reconnect this one to the transformer. Help anyone?

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LOL, he likely spent more money having you put in that transformer than it would have cost for a 480V motor, plus now he has extra losses in the system that will increase his electric bill. But oh well, at least you got a contract eh?...

Do not confuse the "Y" of your power system with the mention of "Y" connections on the motor, those two issues are totally unrelated. That motor is designed to take 200V, which is the correct "utilization voltage" for a 208V 3 phase distribution system, which is exactly what you have now. Just run 3 wires to the motor and be done with it.

Whether or not you need to use Y-Delta starting is also a separate issue, having to do with the load causing a voltage drop or not. At 15HP from a 150kVA transformer, I seriously doubt that will be an issue!

As to "Do I need a motor starter for this unit?" question, I am going to HOPE you meant "Do I need a Y-Delta motor starter for this unit?", because you ALWAYS need a motor starter. But no, as I said you do NOT need a Y-Delta starter in all likelihood.

 

[rlundsrud]

LOL, he likely spent more money having you put in that transformer than it would have cost for a 480V motor, plus now he has extra losses in the system that will increase his electric bill. But oh well, at least you got a contract eh?...

Do not confuse the "Y" of your power system with the mention of "Y" connections on the motor, those two issues are totally unrelated. That motor is designed to take 200V, which is the correct "utilization voltage" for a 208V 3 phase distribution system, which is exactly what you have now. Just run 3 wires to the motor and be done with it.

Whether or not you need to use Y-Delta starting is also a separate issue, having to do with the load causing a voltage drop or not. At 15HP from a 150kVA transformer, I seriously doubt that will be an issue!

As to "Do I need a motor starter for this unit?" question, I am going to HOPE you meant "Do I need a Y-Delta motor starter for this unit?", because you ALWAYS need a motor starter. But no, as I said you do NOT need a Y-Delta starter in all likelihood.

Just So the OP (and me) are clear, he would be connecting it for the delta configuration, which is the left diagram. The Y start delta run configuration is for reduced starting current and would use an interlocked or Y-delta starter instead of a single delta starter.

 

[Jraef]

Just So the OP (and me) are clear, he would be connecting it for the delta configuration, which is the left diagram. The Y start delta run configuration is for reduced starting current and would use an interlocked or Y-delta starter instead of a single delta starter.

Whether or not the internal connections INSIDE of the motor are Wye or Delta is immaterial, don't get bogged down by that, in fact it confuses a lot of people. But you are correct in that what that diagram is saying is that if you WANT to start it with a Wye-Delta starter, which means an EXTERNAL connection pattern, that is how you would connect the 6 wires necessary to go to that motor to accomplish that, but that nameplate is crap, because it is totally unclear about that detail!

 

[DrSparks]

LOL, he likely spent more money having you put in that transformer than it would have cost for a 480V motor, plus now he has extra losses in the system that will increase his electric bill. But oh well, at least you got a contract eh?...

You have no idea... We're talking about a guy with money though. He started building an addition and decided it wasn't big enough and told the concrete guy to abandon the 12" concrete footing he had just poored and start over. We're getting there though. It's all T&M!

Also, Eaton sent us the wrong spec on the switchgear. Madison Gas & Electric requires cold-sequence metering. The sent us the opposite--and my switchgear salesman sent them MG&E's spec. Eaton sent out a crew with a fabrication shop in a trailer and rebuild the entire bus. Took them half a day. I was amazed.



Plus the CTs wouldn't align with the holes. lol



Thanks for your help guys. We got it figured out. It was wired properly, but the motor windings are shot. He's going to order a new 15HP 480 motor

 

[Electric-Light]

That motor's not meant for 240v service. No wonder the winding's shot :roll:

The nameplate is perfectly clear.

It means that wye operation is only meant for starting and if you use it continuously in wye, it will burn out. The unloader keeps the load off the compressor as it starts up. Wye starting essentially does the same thing as starting on 120v and switching over to 208v by speed, current, or elapsed time. It lowers the voltage sag during starting and reduces wear and tear on belt, bearings, compressor, mounts, etc.

 

[hurk27]

If the old service was a 240v delta and this existing compressor had a 230 volt rated motor it most likely would not last long on 208 volts as an air compressor is a high torque application and the correct motor would have been a 200 volt rated motor, so yes changing it to a 200 volt or a 460 volt rated motor would have been the correct move.

Most high torque applications won't allow a 208-240 volt motor rating as it is too much for the motor to handle, on a 208 volt supply a 200 volt rated motor would be the correct rating, but since you have 480 then why not save on the wiring to boot?

 

[hurk27]

That motor's not meant for 240v service. No wonder the winding's shot :roll:

The nameplate is perfectly clear.

It means that wye operation is only meant for starting and if you use it continuously in wye, it will burn out. The unloader keeps the load off the compressor as it starts up. Wye starting essentially does the same thing as starting on 120v and switching over to 208v by speed, current, or elapsed time. It lowers the voltage sag during starting and reduces wear and tear on belt, bearings, compressor, mounts, etc.

The OP said he had a 240 volt service so I would expect that the original motor was a 230 volt rated motor, but they installed a 480/208-120 volt transformer and tried to run it on 208 which like I said above it should have been a 200 volt rated motor for 208.

 

[hurk27]

Whoops, I just saw the motor plate in the OP and your right it does say the motor was a 200 volt rated motor, which would have been perfect for a 208 supply???? wonder why they had it on a 240 volt service unless this compressor wasn't existing with the original service?

 

[DrSparks]

Whoops, I just saw the motor plate in the OP and your right it does say the motor was a 200 volt rated motor, which would have been perfect for a 208 supply???? wonder why they had it on a 240 volt service unless this compressor wasn't existing with the original service?

The building originally had two services: a 240 delta and 240/120 single phase. The compressor has been running for ten years on a 240 delta service. Probably finally had it from years of over-voltage. We'll be getting a 480V motor to replace it. The transformer will be used for some lighting, a couple of old air handlers, and general use receptacles.

 

[hurk27]

The building originally had two services: a 240 delta and 240/120 single phase. The compressor has been running for ten years on a 240 delta service. Probably finally had it from years of over-voltage. We'll be getting a 480V motor to replace it. The transformer will be used for some lighting, a couple of old air handlers, and general use receptacles.

Just make sure what you put on the new 208 voltage will handle it, the air handlers will pull a little bit more current if they are 230 volt rated motors, but for the most part they should run fine on 208, any high torque applications should be looked at such as air conditioning systems as some don't like 208 and some are ok with it.

 

[Electric-Light]

Just make sure what you put on the new 208 voltage will handle it, the air handlers will pull a little bit more current if they are 230 volt rated motors, but for the most part they should run fine on 208, any high torque applications should be looked at such as air conditioning systems as some don't like 208 and some are ok with it.

The official voltages are 208 and 240v.
Motor name plate values are 200 and 230 respectively.

208-230 motors are a compromise and it's generally for smaller motors. It's an inevitable answer to prevalence of both voltages. Small AC units (<5 hp) are designed for 240v and 208v service.
Places that are fed with delta service are 240v while wye service is 208/120.

Larger motors are more likely to have dedicated 208 or 230v requirements.

The building originally had two services: a 240 delta and 240/120 single phase. The compressor has been running for ten years on a 240 delta service. Probably finally had it from years of over-voltage. We'll be getting a 480V motor to replace it. The transformer will be used for some lighting, a couple of old air handlers, and general use receptacles.

Are they dedicated 120v lights? Why aren't the lights running on 277v?

 

[DrSparks]

The official voltages are 208 and 240v.
Motor name plate values are 200 and 230 respectively.

208-230 motors are a compromise and it's generally for smaller motors. It's an inevitable answer to prevalence of both voltages. Small AC units (<5 hp) are designed for 240v and 208v service.
Places that are fed with delta service are 240v while wye service is 208/120.

Larger motors are more likely to have dedicated 208 or 230v requirements.



Are they dedicated 120v lights? Why aren't the lights running on 277v?

Anything new we're installing have universal 120/277v ballasts. There are a few keyless fixtures and existing concealed wiring fixtures that we don't want to touch. 90% of the lighting is being rewired and put on contactors.

 

[Jraef]

The official voltages are 208 and 240v.
Motor name plate values are 200 and 230 respectively.

208-230 motors are a compromise and it's generally for smaller motors. It's an inevitable answer to prevalence of both voltages. Small AC units (<5 hp) are designed for 240v and 208v service.
Places that are fed with delta service are 240v while wye service is 208/120.

Larger motors are more likely to have dedicated 208 or 230v requirements.

Bingo, and the cutoff point tends to be 10HP, meaning most off the shelf motors 10HP and under are going to be 208-230V rated, meaning they are a compromise design and the differences are minimal enough to not be fatal, but above 10HP that becomes more critical. The Cowern Papers from Baldor offer a good explanation of that issue.

 

[norcal]

It's been a while since I have ordered a I-R compressor, but they offered a 230/460V rated motors or for 208V a 208 (it's been a while) or 200V single voltage motor, they did not offer a tri-volt 208-230/460V compressor motor. It kind of sucks when moving to another building or buying a used one & 208V is not avail. when it has a single voltage motor.

 

[GoldDigger]

You could always use buck transformers....

 

[Electric-Light]

It's been a while since I have ordered a I-R compressor, but they offered a 230/460V rated motors or for 208V a 208 (it's been a while) or 200V single voltage motor, they did not offer a tri-volt 208-230/460V compressor motor. It kind of sucks when moving to another building or buying a used one & 208V is not avail. when it has a single voltage motor.

It happens, because things are designed around 120v here. Third world countries like Mexico and Guatemala have something weird like 220Y/127V I suppose that's the real application for 130v bulbs.

I read that third world countries that's just starting to get power now are standardizing on IEC 400Y/230V 50Hz . Multiply by 6/5 and you've got 480/277, so light industrial motors exchange nicely between here and Europe as long as you can address the speed differences.