# Faulty Transformer?



## Wirenuting (Sep 12, 2010)

Welcome to ET,

Please finish filling out your profile.


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## frenchelectrican (Mar 15, 2007)

Please fill your profile as you will see it on user CP on upper left corner of the screen that you can fill it in. 

( you may have to use the desktop verison to get this running correct )

that is a 4 wire delta transformer.


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## Richie V6 (Jul 17, 2019)

Profile filled out. Thank you gentlemen.


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## CoolWill (Jan 5, 2019)

3400 kWh... As in 3.4 MWh?

Your loaded transformer drawing 35 amps would use that in about 117 hours. How long were you moving and are you sure there was no previous balance on the bill?


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## joebanana (Dec 21, 2010)

Looks like your panel is out of balance. What is your electrician smoking? "sending unbalanced power"? It's not what they're sending, it's what you're drawing. 11.5 A unloaded on L3 along with 34.5 A loaded on L3 (with 11.4 on L2), needs further investigation. Have you done a visual on the xfmr.?


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## Cow (Jan 16, 2008)

It's a 240v delta configuration on the low side. I'm not surprised to see A and C phases more heavily loaded than B. That's typical.

I can't help with the idle current though, I don't have a 150kva to measure. 

If I take your primary current amp readings with no load:

8+8.4+11.5=27.9/3=9.3 amp avg/phase

9.3 x 480 x 1.732=7732 w/hr=7.732 kw/hr

3400 kw/hr / 7.732 kw/hr=439 hrs/24 hrs day=18.3 days to get 3400 kw/hr of power consumed.

I also think your electrician may be out of his depth when he thinks the utility is sending unbalanced power even though you posted it's all within 3 volts under load(491-494)......

You may be able to request another service to get your lower voltage house power, with service installation and monthly meter charges, the payback may be a ways out there.


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## Richie V6 (Jul 17, 2019)

Thank you all for the help. They sent out another electrician yesterday to do some measurements. They are going to call the transformer manufacture and see what the transformer losses should be. Without knowing the power factor we can't come to any conclusions.


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## Weasel (Jul 14, 2019)

Is the transformer bonded to a good earth ground terminal X0


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## Richie V6 (Jul 17, 2019)

Weasel said:


> Is the transformer bonded to a good earth ground terminal X0


I will have to check and get back to you.


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## Southeast Power (Jan 18, 2009)

I would say to shut down the transformers or put a load on them.


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## micromind (Aug 11, 2007)

The figures in the first post sound pretty close to what I'd expect from a 150 KVA transformer. 

The difference between them doesn't surprise me at all.


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