electric motors

[Boko2008]

My church lost power in Hurricane Ike. The power company connected only 2 of the 3 leads to our three phase electric supply circuit (we have some very big AC systems). We have only 80 volts on our electrical outlets. Is it safe to run a refrigerator (designed for 110-120v)at 80v?

 

[jraef]

No.


"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[itsmoked]

NO x 2!

And if you run ANY 3 phase motors(A/C) they may be destroyed in seconds.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[7anoter4]

Only if it is an absorption refrigerator. But better buy an absobtion refrigerator working on gas.
Regards

 

[jraef]

And if you run ANY 3 phase motors(A/C) they may be destroyed in seconds.

Awww, c'mon. I bet it would take a few minutes, assuming the OL relays don't trip, before there would be actual destruction. Damage, yes. Destruction? That would take a meltdown.

Side note: Some friends living in Houston called because they were supposed to meet my wife at the airport Saturday on her way down to Mexico. They are not going because they still cannot get gas. All of the gas stations in their suburb are still without power so they can't pump. This amazes me; gas stations can't afford portable generators?


"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[itsmoked]

Yeah Jeff a very common "I don't get it". Talk about 'lost opportunity' in sales.

We see refrigeration compressors destroyed, (failed) if you rather, in less than a minute due to single phasing and often the O.L.s don't trip. And when a hermetic or semi-hermetic have an insulation problem it is a melting issue that can wreak havoc with the entire system. Acids are created in the melting that attack everything. All you need is the refrigerants to exceed some fairly low temperature and the acids form.

If the the motor is started in a single phasing situation it is a race with the OLs that the compressors often win. (Lose!)

Keith Cress
kcress -

http://www.flaminsystems.com

 

[jraef]

D'OH! Forgot it was a refrigeration compressor....


"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[electricpete]

I'm guessing the refrigerator is not a 3-phase refrigerator (?)

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[electricpete]

Actually it is a question. I am not familiar with commercial (vs industrial) type stuff. Is there such a thing as 3-phase 120vac?

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[waross]

There's 120/208V three phase. If it is a standard connection plug it will be single phase.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[electricpete]

Thanks Bill. I would call that 208v 3-phase rather than 120v 3-phase. The question I am really trying to get at:

The original post stated "Is it safe to run a refrigerator (designed for 110-120v)at 80v?"

Is there some reason to think this refrigerator is 3 phase?

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[BobM3]

Why would he have 80 VAC at the 115 volt outlets? Wouldn't it be either 0 or 115 volts depending on which phase the outlet was connected?

 

[jraef]

Electricpete,
No there are no 120V 3 phase appliances like that. 120V would explicitly imply single phase.

BobM3,
I think he was meaning he was getting an unusually low voltage on the 120V circuits in addition to having one of the lines down, which indicates an additional serious problem, making it unsafe to operate anything.


"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[itsmoked]

We have a rail car with true 120V 3ph but it is a r a r e bird! (thank goodness!)

Keith Cress
kcress -

http://www.flaminsystems.com

 

[davidbeach]

Submarines also used 120V 3-phase.

 

[LionelHutz]

I wonder if he's got a delta-Y connected transformer between the utility 1-phase connection and the church that is creating this low voltage? If so, I would keep checking the other outlets. An outlet connected to another phase may actually provide 120VAC.

 

[waross]

What I said was "120/208V three phase" NOT "120V three phase".
I suspect that he has a utility version of the blown main fuse syndrome. The third phase is being back fed by a series connection through phase to phase connected loads.
Thanks LionelHutz for the excellent suggestion. It may well be only one phase that is affected.

Bill
--------------------
"Why not the best?"
Jimmy Carter