rlb0319

We are in the process of changing out a VFD for a 13000Hp motor. All of the medium voltage power cable is also being replaced. does anyone have a suggestion as to verify rotation before we hook up the leads.

Boneshaker

13000 horse power?

rlb0319

That is correct. 12kv

MDShunk

If it doesn't have something like "A-B-C Clockwise facing shaft end" noted in the motor paperwork, you might have to get primitive and spin it by hand with a rotation meter hooked up.

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-Marc, ABC, XYZ, PhD, 1-2-3

-Someday, I'll wear pajamas in the day time.

Peter D

Or just hook it up, see how it spins and then change it if necessary? Probably easier said than done with 15 KV rated cable.

rlb0319

The motohas to turn CW due to it is currently connected to a compressor. The power leads are being replaced along with the VFD. I am trying to figure a way to make sure I have a CW rotation when I connect my leads.

MDShunk

Depending on how cramped the wiring compartment is; yes, sometimes easier said than done. A guy could always sacrifice a set of elbows and hook them up long first, to see which way it goes. That's sorta rookie, though.

__________________
-Marc, ABC, XYZ, PhD, 1-2-3

-Someday, I'll wear pajamas in the day time.

MDShunk

OOOhhh... Then someone seriously F'd up when they didn't mark things before they torn it down to put in the VFD. If you put it all back the same way, the VFD will have you spinning the right way. There's really no harm in having the compressor spinning the wrong way for a little bit. You'll see the gauge start to go backwards. No biggie. The only time this is a big deal is with a rotary vane compressor, but you're probably dealing with a screw compressor if it's that big. Those same compressors serve vacuum duty too, and it might even have a phase reversal relay if it's got some feature that would break if it ran backwards.

__________________
-Marc, ABC, XYZ, PhD, 1-2-3

-Someday, I'll wear pajamas in the day time.

Peter D

What type of facility requires a 13,000 HP air compressor? Glass bottle plant?

Bob Badger

It's what I use to inflate my head.

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Bob Badger
Electrical Construction and Maintenance
MA, RI, CT

MDShunk

Some industral parks have a central compressed air location, and they resell it to each tenant and meter it like a utility.

__________________
-Marc, ABC, XYZ, PhD, 1-2-3

-Someday, I'll wear pajamas in the day time.

drsparky

This question is also posted in tool and equipment section.

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Peter D

Nah, I think you need a 50,000 HP minimum. Speaking of which, I hear the only door you fit through now is your garage door.

rlb0319

It is a natural gas compressor at a pipeline compression facility

MDShunk

Oh, then it's certainly a screw. It's not a Frick compressor, by chance, is it? I know Frick makes a lot of natural gas compressors.

__________________
-Marc, ABC, XYZ, PhD, 1-2-3

-Someday, I'll wear pajamas in the day time.

InPhase277

Maybe it doesn't work this way for medium voltage stuff, I don't know. But can you "bump" it?

Boneshaker

I agree with Shunk, if someone took this apart without any documentation he ed up. Leave your terminations as long as possible, (without causing a goat f---) check rotation and swap as needed. You probably wont be able to acomplish this in the VFD but may be able to back at the feeder compartment. Easier said than done I know, but you don't have a lot of options at this point.

wwilson174

If you know the phase sequence of the power supply and you know the arrangement of the field coils in the stator ( available from the manufacturer) then you know in which direction the motor will rotate. This presumes that we are discussing an induction motor. BillW.

frenchelectrican

What you should have Med / High voltage phase rotation tester and veirfiy the rotation sequince.

I know most POCO supply useally marked ABC or tape bands one of few common way { in Europe it will marked RST }

Veify it on the line supply to see if that line up and keep in your mind from time to time you may see phase rotating buss { it will show up once a while but not a whole alot unless you have hevey current drawage MV /HV set up.

Merci,Marc

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Pas de problème,il marche n'est-ce pas?"(No problem, it works doesn't it?)

micromind

A few things come to mind here;

1) The output of every VFD I've ever connected at any voltage has always been A-B-C. Regardless of the input rotation. If it turns wrong, does the VFD have a reverse feature? And can it be locked in reverse? Some of the medium voltage VFDs I've worked with can be programmed to lock out either forward or reverse.

2) If the motor can be un-coupled from the compressor (probably not easy at 13,000HP), and the shaft can be turned by hand, blast it with some 480. It likely will not turn by itself, but it'll be easier to turn by hand in one direction than the other. Then measure the 480 rotation.

3) A lot of huge motors I've connected use differential protection for fault detection. If this is the case, and the rotation is changed by reversing leads, remember to change the CT secondary leads at the VFD output to match the opposite side of the motor. (Personal experience speaking here, I sure feel dumb sometimes!)

Rob