Hyd pump motor probs

[treblemaker]

The motor is on Y-start/D-run with three contact blocks; One for Y with the leads shorted, this is wired to 10,11, & 12. One for Delta going to 1,2,3. And one for timing out the Y-D blocks. The motor starts but trips the 100A cb @ the 480 panel after the Delta contact block closes. No fuses go. Any ideas what might cause this? I checked the control circuit and all the starter contacts. Next direction should be the connections at the motor, but I'm assuming they're right. The motor was just replaced and hopefully my apprentice electrician got it right. The old wires were U,V,W & X,Y,Z so perhaps it confused him. Any help is appreciated.

 

[Skogsgurra]

Before you have sorted out how the wires to the motor go, it is difficult to say anything at all. Most likely thing, as I see it, is that the direction of rotation is one in Y and opposite in D. That would cause a trip when going to D.

Gunnar Englund

http://www.gke.org

--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[jraef]

The motor was just replaced and hopefully my apprentice electrician got it right.

Such is the main problem with people using Y-Delta starters.

If there is any mis-connection of the conductors, there are a number of problems. Start here, have your electrician read and understand the proper connections of the motor.

http://www.patchn.com/motor_connections.htm

Then look at a typical Y-Delta wiring diagram like this;

http://www2.sea.siemens.com/NR/rdonlyres/D8268364-8C82-438D-83FE-7B31F6445D78/0/D68854006D.pdf

and have your electrician try to make them relate. If he can't, hire a professional or junk that Y-Delta starter and put in a soft starter connected in just plain Delta.