200kw Motor 3 Phase Off Load Amps

Unloaded amps mean next to nothing. The power factor is so low that what you are reading is essentially meaningless. But it would not be the star-delta starter wiring that would be incorrect, it would be the motor connections if anything.

the motor connections a1,b1,c1,a2.b2,c2, 6 -wire -will check the powerfactor.

2 machines that they drive are pelleting boas-we set them at min amps eg 80 amps and run them about 150 -200 amps.but the identical machine which runs at 120amp starts high and needs to get up to 250 to do the same work-machine blocks at 300 amp-jack hammer time.

If you check the power factor you can make a good estimate of consumed electrical power, and so also mechanical absorbed power.

If this is much different between the two motors then the load on one is much higher so you would need to find out why.

The no load current of the same design motors should be similar but you can't use power without it being absorbed / used somewhere!

fyi, on old Brook data, fla is about 325A and no load about 70A for a 200Kw 4 POLE on 415V.

It sounds like one machine is using a lot more power than the other to me if these are equivalent motors.

You say they were removed from load for test:
What was the on load current for each motor?
What made you take them off load for testing?

the machine we use the motors on is a boa mixer.

we tune the machine from normal running amps to full load amps but with 1 motor running at 120 amps no load and the other 80 amps no load then our 2 machines tend not to function the same,because of the no load amps difference 1 machine starts higher doing its job were the lower can do its work by 130 amps.

euro motor cheap -contractors say its wound wrong-2 ton to shift and roof coming off the factory again

Unloaded amps can be quite a high percentage(maybe >50%) of the full-load-amps. So nothing to worry there. Please read more about motors and drives here : http://www.motorsanddrives.com/cowern/motorterms16.html

thanks for the link-the motors drive a pelleting boa which works between no load to blocked at 300amps.with 1 motor starting at 80 amps its range is longer than starting at 120 amps-300 amps,normal running amps of the boa is about 150amp to 200amp but the other starts at 120 and we need to run it higher to get the same work out of it.also its closer to blocking .i will check the pf and motor connection .thanks for getting in touch

will check the power factor-thanks for the reply-the machines dirve a boa pelleter for animal feed and with 1 starting at 80 amp and the other 120amp -we are looseing 40 amps of work out of 1 machine.

In this problem there are two possibilities.

1. The star delta starter does not connect to the proper corresponding terminals of the motor windings. In that case , the motor will not draw balanced currents in 3 lines.Check the currents in the lines and if they are not balanced, then check the motor terminal box to veryfy and if necessary correct the winding connections.

2. If the currents in 3 lines are balanced then one possibility is that the motor which is drawing less current is remaining connected in star and is not changing over to delta. Pl check the star /delta starter for proper operation.

Priyadarshan

One (maybe stupid) question - Were the currents measured with the same meter for both motors, or do the motors each have ammeters associated with them, which could be out of calibration or incorrectly scaled?