Electrical Question

[Firstram]

We are setting up shop for the next 2 months on a show. My air compressor has a 7 1/2 hp single phase 208 volt motor. The power in this building is running a little high. I'm getting 130v from all lines to N and 230v from line to line. Thats a smidge higher than the 10% rule, will I let the smoke out if I don't buck the volts down?

 

[JimDawson]

I think you'll be OK. Those are some odd voltage numbers. Is that a 3 phase 208 system in the building?

 

[MikeInOr]

230v should not be a problem at all.

 

[Firstram]

I think you'll be OK. Those are some odd voltage numbers. Is that a 3 phase 208 system in the building?

It is supposed to be 208 and they are strange #'s. The voltage has been the same for the last week so I don't think I was reading a spike. I'm more worried about getting a spike and cooking the motor!

 

[JimDawson]

My voltage here was running 250 - 255 for months until they changed the transformer. Didn't cause any problems.

 

[Firstram]

My voltage here was running 250 - 255 for months until they changed the transformer. Didn't cause any problems.

This was on 208 3 phase equipment?

 

[JimDawson]

It was running some 208 rated equipment, but I was running everything on single phase.

 

[Firstram]

Sounds good, Thanks

 

[rabler]

Generally under voltage is much more problematic. Less voltage means more current. More current means more heat, proportional to I^2 x R.

 

[Superburban]

Here is a good explanation on 208 vs 240 volts. You need to scroll down a bit.

What’s the Difference Between 208v and 240v? - HVAC School

By:Bryan Orr The easy answer is 32v. Class dismissed. I’m only joking, of course. Finding the difference between 208 and 240v power supplies may sound quite simple, but there are some pretty sharp fundamental differences. Apart from the obvious differences in overall voltage, 208 and 240v power...

hvacrschool.com