Eutopean motor connection

[oldfieldguy]

Quick one, guys...

I have a three-phase motor of European origin. The motor leads are numbered U1,U2,V1,V2,W1,W2.

I need to connect for higher voltage. I'm guessing the the "2's" connect together and the incoming power goes to the "1's"

No nameplate data available. It's 380v -50 Hz, and the vendor says it will be okay at 480v - 60Hz.

Help! I'm at the jobsite right now waiting.

old field guy

 

[edison123]

What is the HP ? Normally, 6 leads are brought out star (start)/delta(run) operation.

(How come the vendor doesn't know or give you the nameplate details ?)

 

[oldfieldguy]

edison123--

It's a packaged axial blower for a emissions controlling combustion enhancement for a gas turbine, and it's a vendor package. We're talking one horsepower.

It looks German, but to get to the motor itself we'd have to do a complete teardown of the blower since it's mounted inside the duct. The six leads are brought out to a terminal box mounted on the external surface of the blower.

old field guy

 

[edison123]

Ok. That motor will be direct-on-line start.

To make sure it is not a part winding start motor, ensure there is no continuity between U1, V1 and W1.

If there is no continuity between phases, then it is a 6 lead motor.

To be on the safe side, go with your method (short all 2's and supply 1's). If that doesn't get the fan up to the speed, then you can connect in delta (Connect U1V2, V1W2 & W1U2).

If there is continuity between phases, it is a part winding start (though I don't see the necessity for this small motor). In that case, you need suppl U1, V1 & W1 and when speed is obtained, throw in U2, V2 & W2 (you need special contactors to do this)

In all cases, check the direction of rotation.

 

[oldfieldguy]

Edison123

Excellent... That's sort of what I was thinking, but it's nice to have somebody else say it.

I just LOVE these packaged units with no electrical information...



old field guy

 

[Marke]

Just to be sure, try to separate the fan from the motor so that you can run it open shaft. Connect in star and run the motor unloaded and measure the unloaded current. If the current is less than 30% full load current, it should probably be delta connected. I would expect to see an open shaft current between 40% and 60% of full load current. If you run it in star when it should be connected in delta, you will have a higher slip and eventually melt the rotor.

Best regards,

Mark Empson

http://www.lmphotonics.com

 

[oldfieldguy]

After some period of time while I was looking into other problems, one of the electricians brought me in the nameplate that they SWORE wasn't there, and behold, the proper connection information was on the nameplate.

Of course, I told them to read the nameplate earlier, but they swore it wasn't there.

The answer from the nameplate was exactly in line with the information from Edison123. It's a dual-voltage winding and should be connected wye for our application which uses the higher voltage.

When I presented this information to them, I had to do a dissertation on why and how a wye-connected winding would work with our 480 volt delta-connected transformer. Sometimes I am amazed at the things that people KNOW that just are not true, but they merrily run along in life anyway...

old field guy

 

[HCBFlash]

Wow, I got all excited for a minute! The threads title sounded too good to be true!

Eutopean motor connection

I thought the apparent misspelling simply had added an E at the start of the word!




But then what fun would a thread be without those nasty little details that would show up on a thread with a different mis-spelling!

 

[edison123]

HCBFlash

It is Utopian, not utopean ... yeah, I know, nasty little detail.

 

[oldfieldguy]

Oh, rats!...

I can spell a lot better than I can type.

And compared to the gas turbines and reciprocating prime movers endemic in my industry, ANY electric motor is quite utopian enough, thank you!



old field guy

 

[HCBFlash]

I'm laughing with you oldfieldguy, certainly not at you! The backspace key is the only one my my keyboard with the character almost worn off of it.

More and more (maybe younger and younger) people just let their word processors and spell checkers deal with all that stuff. I wonder how many youngsters have to have someone explain the origin of the term "typing"?

Of course there is another forum or 2 on this site for going into all this stuff.........