575 Volt System. ??

I am beginning work on my first control system for some machinery that will be located outside the U.S.
The primary supply voltage will be 575 rather than 460-480 that I am used to working with.

It is a Considerable control system with PLC/HMI onboard will talk to a central plant office somewhere via a SCADA system or Wonderware etc.(done by others).

Several motors will be involved up to 20 HP. at least one Across the line reversing motor and several VFD driven motors. (Powerflex 70's Likely).

I would just like to know what things I should watch out for with the 575 Voltage As I layout the control and MCC etc..

For the most part everything will stay the same as a 480 machine it appears. Of course the motors will be rated 575...

Anyway, is there anything I should watch out for such as landmines....??

600 volt-rated conductors that you would normally use in the US probably will not be adequate for 575 volt equipment, as the peak voltages could be well above 600. The same applies to MCCs, contactors, starters, transformers, and other equipment.

We are 575V here and we use the standard 600V rated everything for our wires/contactors/relays/etc. The only thing to watch is the VFD input voltages, sometimes they are dual 480/575 and sometimes they are not.

For the VFD output wires you might want to look at higher rated insulation, 1000V wire might be best for those, as they do peak well above 600V.

Reactors in front of all the drives

I suggest making as many control circuits and I/O as possible DC. That eliminates many issues.

575v is mostly unique to Canada so i expect you send it there?
everything seeing 600v must be rated at least for 600 V. Parts with just 480v insulation won't be accepted and can cause isolation or short issues.
Breaker/switch/contactors

I also suggest you use at least cUL approved parts to be easily approved here. Manny UL ones bare a cUL approval also...

I suggest you use 600+ max volts rated VFD because our 600v could be without any problem 5% over (630) and sometimes a little more in new area....
As stated, dont forget input and output choke.

Be aware of reducing your wire and device size for lower amperage

You may use different drives/starters. Just be sure to use the 575V ratings for components when you're specing them out instead of the 480V rating.

Jeff23spl said:

I suggest you use 600+ max volts rated VFD because our 600v could be without any problem 5% over (630) and sometimes a little more in new area....
As stated, dont forget input and output choke.

Click to expand...

We have that issue here as well. We run some VFDs without chokes and our nominal voltage when running is around 603V. Some days we see drives tripping on over-voltage for no reason other then the line voltage is higher then expected.

I agree with the cUL or CSA stamps. We've had panels rejected here because they used breakers without a CSA stamp. Something to watch carefully.

Sorry it took me a while to get back here today. Thank you all for the help and advice. Many of the suggestions I wouldn't have thought of until it was too late..

Yes this is a system going to Canada and will be very remote as well so voltage fluctuations could easily be a problem..

Thank you all !!!

My next question would be what about the control transformer?

I generally use ACME control transformers...

One thing that is important to consider.
The current breaking capacity of circuit breakers drops with increasing voltage.
So you may not be able to meet the required short circuit breaking current level required using the circuit breakers you are used to.
You may have to go up in circuit breaker size, or switch to fuses for the biggest consumers.

Actually, I would like to rephrase that.

Designing for a certain voltage is something that a capable panel builder should know already.
If you have to ask such a question you should leave it to a panel builder, or at least involve a panel builder.

milmat1 said:

My next question would be what about the control transformer?

I generally use ACME control transformers...

Click to expand...

Everything is remote up here. We are all in igloos.

The ACME transformers will be fine provided the primary is 600V rated. Because this is kind of a Canuck thing you will sometimes find equipment up here with 600V transformers on 480V supplies or Vice Versa. OF COURSE THIS IS NOT RECOMMENDED but I work in the real world and have seen it happen.

Do you know what kind of distribution set up you will be tying into? Resistive grounded systems are more popular here than they are in the US I do believe. I don't like them but some places have them including my current place of employment. Pay very close attention to the installation instructions of the drives particularly Pflex drives in this type of installation. There are some jumpers you have to remove from Pflex drives to use on this type of system. If you don't the first time there is a ground fault on anything downstream of the resistively grounded TX on this type of system the drives will blow and you will get to find out exactly what they put in electorlytic capacitors (hint it's runny and it stinks when burnt). Yes I found this out the hard way and it was an expensive lesson.

Reactors between the VFD's and the motors for sure. But, not necessarily in front of the drives. Depending on the brand and model of VFD, there may already be a 3% reactor in the standard furnish. Adding another reactor in front of such a drive will result in low voltage problems at heavy loads.