Power/Signal Cabling

Could someone please explain the problems of having power and signal cable in the same cable tray. I am experiencing proplems with some pump motors tripping out on high current and suspect the problem is electrical rather than process or mechanical.. The power factor for each ~60%, which I have been informed is v. low. Typical readings are Current 20.2 A (motors rated at 20.5A), Measured Voltage 420 V and POwer 8.8 kW.

Apologies if this is a very basic question, but I am not an electrical engineer.

 

[gce1991]

The problem is not with the power/signal cable it is the problem with the Power factor of the motor Check whether the PF improvement capacitor are switch on and working Always maintain the PF above 0.85 (Minimum) the motor load current will comedown drastically if you improve the power factor to 0.85 atleast .

The problem with Power and signal cables in same tray will only affect the signals beeing carried in the signal cables

 

[electricuwe]

eswarelctrical,

your post is a bit misleading. Usually (as long as no harmonics are involved) capacitors will reduce the current in the line, but not in the motor. So after adding capacitors the motor will continue to run close to it's rated current. Adding capacitors will raise the voltage at the motor terminals. Unfortunately we can not check how this will take influence on motor current since Jackie W didn't give the nominal voltage of the motor.

460 V motor --> reduced current
400 V motor --> increased current due to overexcitation

 

Thanks for the responses guys,
(Nominal Voltage og Motor is 400 V)
If I do get to the bottom of this I will let you know