Single phase from three phase generator?

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switchleg45

Member
Location
Ft Myers,FL
My client has a 30K, 3PH generator. He wants to use it to provide emergency power to his walk-in coolers for his seafood business.
Question: If you load just two of the windings (phases?) will the third, unused winding be adversely affected? Or, is there a transformer configuration to convert 3PH to 1PH?
 
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cpal

Senior Member
Location
MA
how many 1p loads will be fed from the Gen??
you should be able to somewhat balance the load.
 
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hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
If only single phase loads are going to be used, check the generator for re-configurable connections to single phase, I have a 30 kw Kohler at my house that started out as 480 volt three phase, but can be configured as 120/240 delta three phase or 120/240 single phase. I opted for 120/240 delta so I could test three phase motors, since my service is single phase. Not all generators have this capability, so check with the manufacture.
 
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hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
Four cylinder turbocharged dual fuel, runs on natural gas or propane automatic switchover to available fuel. 1800 rpm, so quiet that I can not hear it in the house with the windows closed. Can't beat the price either, replaced it with a 80KW for the customer, Left it on site, customer called and asked if I was going to get rid of it, they didn't want it! 648 hours on, and not a thing wrong with it!:grin:
 
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techntrek

Member
Location
MD
Wow, that was a good deal! With that much juice available, you can run every circuit in the house w/o worrying about load management. Of course, downside is it probably uses 2-3 gallons of fuel an hour at half-load? My 12kw LPG uses 1.5 at half-load, which isn't cheap when the power is out for a few days.
 
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BenS

Member
Is this just for the coolers? The load is going to be intermittent anyway as the compressors cycle on and off. If this is the case, its probably not possible to achieve any sort of meaningful balance. I would check with hillbilly1's suggestion and see of it is possible to configure the generator for single phase operation.
 
Smart $

Smart $

Esteemed Member
Location
Ohio
BenS said:
Is this just for the coolers? The load is going to be intermittent anyway as the compressors cycle on and off. If this is the case, its probably not possible to achieve any sort of meaningful balance. I would check with hillbilly1's suggestion and see of it is possible to configure the generator for single phase operation.
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I don't know about you guys, but I'm rather curious of the operating voltages of both genset and loads before pronouncing genset winding reconfiguration as the overall best solution.
 
Rick Christopherson

Rick Christopherson

Senior Member
Smart $ said:
I don't know about you guys, but I'm rather curious of the operating voltages of both genset and loads before pronouncing genset winding reconfiguration as the overall best solution.
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I have written 3 responses to this thread and deleted all of them before posting.......why?..... For this very same reason.

The answer is easy, but without the specifics, there are too many other aspects that have to be covered. Covered needlessly.
 
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Cold Fusion

Senior Member
Location
way north
switchleg45 said:
My client has a 30K, 3PH generator. He wants to use it to provide emergency power to his walk-in coolers for his seafood business.
Question: If you load just two of the windings (phases?) will the third, unused winding be adversely affected? Or, is there a transformer configuration to convert 3PH to 1PH?
Click to expand...

Assuming 208V, check to see if it is a 12lead. If so, it can easily be reconnected for 120/240, 1ph. As I recall, you get about 2/3 capacity. A lot of gens that size are 12 lead

cf
 
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switchleg45

Member
Location
Ft Myers,FL
the unit is a Kohler #30R71 (30k standby, 25k continuous), 277/480V. And 'No', it was not purchased for this particular application...it was FREE..and if we can reconfig then we'll put it to good use. Client will feed power to his most valuable inventories first.
I like seafood...
iwire wrote about this subject back on 5-23-09. I believe it can be done. Awaiting word back from Kohler on getting a service manual. He also says it can be reconfigured for single phase. We'll see. Thanks for your thoughts and input.
Question: difference between 'zigzag' and 'double delta'
 
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Cold Fusion

Senior Member
Location
way north
switchleg45 said:
the unit is a Kohler #30R71 (30k standby, 25k continuous), 277/480V. And 'No', it was not purchased for this particular application...it was FREE..and if we can reconfig then we'll put it to good use. Client will feed power to his most valuable inventories first. ---

Awaiting word back from Kohler on getting a service manual. He also says it can be reconfigured for single phase.---
Click to expand...

Before this post, the only scenerio that made sense here is a 208 3ph gen and the customer wanted120/240, 1ph.

Now we know the gen is a freebee 480/277, 3ph and the customer wants single phase (unknown voltage). And the factory says the gen can be reconfigured for single phase.

Rick and Smart were right - not enough information. With the data we have now, there is nothing about this scenerio that looks workable.

cf
 
jrannis

jrannis

Senior Member
Location
Fort Lauderdale/ Miami
switchleg45 said:
My client has a 30K, 3PH generator. He wants to use it to provide emergency power to his walk-in coolers for his seafood business.
Question: If you load just two of the windings (phases?) will the third, unused winding be adversely affected? Or, is there a transformer configuration to convert 3PH to 1PH?
Click to expand...

If you connect it Delta, No. WYE Could be a problem.
Some units cannot have an imbalance of more than 60% without going out on alarm
 
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