Voltage Too High

[Power Tech]

Just got back from a call and the voltage was 492 / 496/ 500.

The wires to the pumping panel were burned up, the reason for the call.

The wire was burned due to a loose connection.

I told the customer to call the POCO and set up a trouble call about the voltage.

He asked me if the voltage being higher would make the current consumed.

I told him we are charged by watts and it could be pulling more because of the higher voltage.

Can anyone set me straight on this?


Oh anyone have a lead on a Square D, size 3 pumping panel fuse clip and switch assembly, 100 amp 480V?

 

[nakulak]

500/480 = 4 % over voltage. I don't see the problem

 

[Power Tech]

500/480 = 4 % over voltage. I don't see the problem

On 408 I don't think the 10% rule applies. I think 500 is too high.

 

[480sparky]

On 408 I don't think the 10% rule applies. I think 500 is too high.

What "10% rule"?

 

[steve66]

I was actually going to come over there and fix it for you until I read your profile:roll:

 

[Power Tech]

What "10% rule"?

I have been told by the POCO's throughout the years, 10% was the differential they call acceptable. Probably BS.

What do you know?

 

[skeshesh]

why not?

why not?

Quote:
Originally Posted by Power Tech
On 408 I don't think the 10% rule applies. I think 500 is too high.


What "10% rule"?

What sparky said.

In any case, what's the problem? is there a motor or something that has an operating voltage range that you're not meeting? I don't see what there is to fix.

 

[LazyS]

He asked me if the voltage being higher would make the current consumed.

I told him we are charged by watts and it could be pulling more because of the higher voltage.


I see nothing wrong with the voltage. And I don't think it will "pull" more because of the higher voltage.

 

[LazyS]

I see nothing wrong with the voltage. And I don't think it will "pull" more because of the higher voltage.[/QUOTE]

 

[mivey]

I think 500 is too high.

You think wrong.

ANSI C84.1 says 504v is fine at the service, and 500v at utilization for a nominal system voltage of 480v

 

[steve66]

A motor will actually pull slightly less current with a slightly higher voltage.

The watts remain the same, and is basically determined by the power it takes to move whatever you are pumping.

 

[480sparky]

I have been told by the POCO's throughout the years, 10% was the differential they call acceptable. Probably BS.

What do you know?

So even if the 'rule' should be only 5%, 500v is still within ?5% of 480.

 

[LazyS]

Okay somebody tell me how to use the quotes so I quit looking like an idiot.

 

[mivey]

So even if the 'rule' should be only 5%, 500v is still within ?5% of 480.

With the motor rated at 460v, it gets closer to 10%.

 

[mivey]

Okay somebody tell me how to use the quotes so I quit looking like an idiot.

Hit the quote button on the lower right of the post. If you want multiple quotes click the "+ key until you get the the last post you want, then click the quote button.

 

[skeshesh]

Yup, agreed that it wouldnt make much difference as far as Watts. That pretty much depends on the power factor and other power quality issues. I guess the effeciency of the motor could change slightly depending on operating voltage but honestly i think these considerations are going too. Just take care of the loose connection that caused the wire fault and it's all gravy.

 

[LazyS]

Hit the quote button on the lower right of the post. If you want multiple quotes click the "+ key until you get the the last post you want, then click the quote button.

I see said the blind man.

 

[mivey]

With the motor rated at 460v, it gets closer to 10%.

Consider Range B values where the motor should be able to operate. The max goes up to 508v. For a 460v motor, that would be +10.4%.

On the minimal side, it goes down to 424v for Range B utilization, and 440v at the service. If there is no lighting, the minimum utilization level can be 416v.

The Range A minimum is 440v at utilization and 456v at the service. If there is no lighting, the minimum utilization level can be 432v.

 

[mivey]

Hit the quote button on the lower right of the post. If you want multiple quotes click the "+ key until you get the the last post you want, then click the quote button.

I see said the blind man.

Now try this.

 

[Power Tech]

You think wrong.

ANSI C84.1 says 504v is fine at the service, and 500v at utilization for a nominal system voltage of 480v

Good to know.