75kva transformer not putting the right voltage or is utility the problem.

[Elect117]

Your line to neutral and line to ground voltage measurements mean more than the line to line. They can tell us if you are experiencing a issue that should be addressed rather than a tap change.

I would also add, that if the transformer is undersized or the conductors are at a minimum that can also cause a voltage issue.

More importantly, make sure they aren't trying to use 230V motors on a 208V. That is a common issue.

And the utility is probably within limits. Most have rules that are about 10% of the designated voltage. Most supply closer to 5%.

5% of 480 is 456V. So anything more than 456V and they might not consider a tap change on the utility side. It could be a shared bank or shared transformer with other customers and if those customers are closer to the source transformer, they would have a higher voltage.

Having lower voltage is typically better than running on the higher side.

 

[augie47]

Take time for a bit of thought to your safety. Those working clearances appear to be lacking.

The entire installation does appear to be an inspector's nightmare

 

[LarryFine]

Would i need to raise taps to get proper voltage on load side?

To answer this as a theoretical question, when you change primary taps, you're applying a given voltage to a different number of primary turns, altering the volts-per-turn ratio.

The intention of having the taps is to set the primary to closely match the actual incoming voltage, so the secondary voltage is appropriate to the load requirements.

So, when you change the primary line to a higher-voltage tap without changing the applied voltage, you actually end up lowering the secondary voltage, not raising it.

To apply this to your situation, where you want to raise the secondary voltage, you would change the primary to lower-voltage taps, closer to the actual applied voltage.

 

[infinity]

Would i need to raise taps to get proper voltage on load side?
120/208v

Look at the nameplate it tells you what taps to use based on the primary voltage.

 

[new-master]

Is the electrical system supplying the transformer supposed to be 460 or 480?

Sorry, I’m not as experienced. But I’m working in the state of Maryland/ Washington DC Area
It was my understanding with experience that I would be getting 480v from utility
I did not utility could also be service 460v


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[new-master]

The entire installation does appear to be an inspector's nightmare

It definitely is a nightmare, would that be NEC compliant anywhere in the country?

Three gas water heaters and a gas furnace in the same room

As far as clearance in front of the panels not acceptable. and I was definitely done afterwards

But if it did have the proper clearance in front of the equipment would it be acceptable to have natural gas in the same room?


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[LarryFine]

It was my understanding with experience that I would be getting 480v from utility
I did not utility could also be service 460v

That's the difference between nominal and actual.

Ask the POCO to measure the voltage you're receiving, and find out whether they can and will raise it.

If not, then changing taps would be the next step.

I have always believed that it's better to receive voltage higher within the appropriate voltage range.

 

[qcroanoke]

If it was working ok and now it's not changing taps would be after exhausting other reasons.
You've Involved POCO. Get their report and go from there

 

[electrofelon]

Sorry, I’m not as experienced. But I’m working in the state of Maryland/ Washington DC Area
It was my understanding with experience that I would be getting 480v from utility
I did not utility could also be service 460v


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Normally it's 480 for sure. There we was a recent thread where someone had a commercial area in New Jersey where the utility served 460, but overall I would definitely say it's quite rare.

 

[tortuga]

I have always believed that it's better to receive voltage higher within the appropriate voltage range.

I agree, especially with 208/120 I'd be tempted to take it up to 212/124.

 

[Hv&Lv]

I wouldn't do anything until I talked to the utility about the low voltage coming in. That voltage is the low end of utility tolerances.
If you change the taps and the utility goes back up to normal voltage you're going to get another call that the voltage is too high.
Chasing something like that makes no sense..

 

[ptonsparky]

I agree, especially with 208/120 I'd be tempted to take it up to 212/124.

I think that is typical for systems here.

 

[ggunn]

I got a call from Customer who said that their transformers going bad and it’s not putting out the 208v as it should only 193v
But also the room temperature really warm about 95°F top of transformer enclosure.

I have to ask: Is this a real problem for the customer or did it just become a problem for him when he measured the voltage?

 

[new-master]

I have to ask: Is this a real problem for the customer or did it just become a problem for him when he measured the voltage?

I got a call because the walk-in cooler condensing motor had been replaced by the HVAC guy, two of the new motors burned that had been replaced.
Motor will run at minimum 200v
While taking voltage reading they been reading 193volts between phase.


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[infinity]

I got a call because the walk-in cooler condensing motor had been replaced by the HVAC guy, two of the new motors burned that had been replaced.
Motor will run at minimum 200v
While taking voltage reading they been reading 193volts between phase.


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So this could have been a problem for quite some time if motors have been burning out. Are they paying you to investigate the entire system or to just fix the immediate low voltage problem?

 

[new-master]

So this could have been a problem for quite some time if motors have been burning out. Are they paying you to investigate the entire system or to just fix the immediate low voltage problem?

I’m getting paid to get to the bottom of it. And fix it
Customer just wanted me to replace the panels and the transformer


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[new-master]

But as of right now, I decided that I will wait to see what utility will tell me there in coming voltage into the building should be.
And I still haven’t been able to access the room where all the meters are I need to schedule with management to access that room.

 

[ptonsparky]

I’m getting paid to get to the bottom of it. And fix it
Customer just wanted me to replace the panels and the transformer


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I'd look for the problem before opening that can of worms.

 

[infinity]

I’m getting paid to get to the bottom of it. And fix it
Customer just wanted me to replace the panels and the transformer

That's good. Plenty of good starting points in this thread.

 

[ggunn]

So this could have been a problem for quite some time if motors have been burning out.

This. If the voltage is the cause of the burnouts and the voltage is not very far under the minimum, the motors could take a long time to show damage.