Hazardous Voltage to equipment

[AJones]

Incoming voltage tests at between 480 and 501 Volts phase to phase. We need to regulate our voltage to about 460-490 Volts because some of our
equipment is sensitive and the absolute limit according to an installation technician is 491 Volts. What can be done as far as a voltage regulator or power conditioner?
The effected circuits are 480V, 80 amp and 35 amp from a 480/277V 200amp service.

 

[petersonra]

It seems to me the manufacturer of equipment sold you a bill of goods. 491 V is well within the standard range of utility power. if they need special power it needed to be mentioned up front. OTOH, the tech may not know. I would contact the manufacturer directly and see what their tech support people say. or read the manual.

If it turns out this is actually true it would seem like something your purchasing people need to resolve. The UCC generally does not allow for this kind of special requirement without it being mentioned upfront.

There are voltage regulating transformers but they often distort waveforms to the point where it might make the problem worse.

In the end if you really need it, your only real solution is a very expensive online UPS.

 

[ptonsparky]

We had a case where the customer was being dinged for poor Power Factor. We made those corrections and of course, voltage went high. We were able to have the POCO change some 'taps' to reduce the incoming line voltage. I don't know what the POCO did exactly and the customer was the only customer on that set of transformers.

Low voltage around here means something is broken.

 

[AJones]

It seems to me the manufacturer of equipment sold you a bill of goods. 491 V is well within the standard range of utility power. if they need special power it needed to be mentioned up front. OTOH, the tech may not know. I would contact the manufacturer directly and see what their tech support people say. or read the manual.

If it turns out this is actually true it would seem like something your purchasing people need to resolve. The UCC generally does not allow for this kind of special requirement without it being mentioned upfront.

There are voltage regulating transformers but they often distort waveforms to the point where it might make the problem worse.

In the end if you really need it, your only real solution is a very expensive online UPS.

Thanks. Before providing any power to anything It tested well with-in the parameters indicated by the manufacturers manual. It is the installation technician who told us "allowable but not recommended".

 

[retirede]

Thanks. Before providing any power to anything It tested well with-in the parameters indicated by the manufacturers manual. It is the installation technician who told us "allowable but not recommended".

Ask him to get that in writing from his Engineering department.

 

[ActionDave]

Thanks. Before providing any power to anything It tested well with-in the parameters indicated by the manufacturers manual. It is the installation technician who told us "allowable but not recommended".

Interesting he's ok with the voltage on the low side of the tolerance for 480V but unhappy with it being on the high side.

Did he happen to mention anything about dirty power or isolated grounding?

 

[AJones]

Interesting he's ok with the voltage on the low side of the tolerance for 480V but unhappy with it being on the high side.

Did he happen to mention anything about dirty power or isolated grounding?

He did not but the manual reads: " machine must be connected to the building ground system" and does have a built in surge protector NOT covered by warranty. We are well within the standards of EN 50160.

 

[Jraef]

You need what's called a Constant Voltage Source (CVS), also sold as a "Power Conditioner". Sola were the original innovators of those, there are others available now. Typically they can accommodate a +-15% swing in input voltage and give you +-3% steady output.

Expensive and inefficient, but it is what it is.

 

[AJones]

You need what's called a Constant Voltage Source (CVS), also sold as a "Power Conditioner". Sola were the original innovators of those, there are others available now. Typically they can accommodate a +-15% swing in input voltage and give you +-3% steady output.

Expensive and inefficient, but it is what it is.

Thanks. We are also contacting our power provider to see if they are willing to make any adjustments on their side. As for the CVS we are looking into it but the cost might not be worth it as the replacement parts are warrantied for a while and the down time is minimum. After the warranty expires we will have to pay for replacement of drivers that they have made locally available.