Star Delta Starter 400KW Crane Motor

[mxj262]

Hello Dear friends,

I am going to check a start delta starter for a motor(400KW) which is used for crane and lately it has been causing some issues (Voltage Drop) not sure if the voltage drop is always there once this is started or it goes back to normal this information was not provided. Will apperiaciate some tips about troubleshooting what is the problem ?

 

[Lucien Nunes]

The readings on your ammeter will be the first and most important guide to what is happening. Are the starting and running line currents reasonable and equal in all lines? Starting current might be 150-200% of FLC, which is probably stated on the motor data plate. Using whatever currents you can get the motor to draw (I appreciate you probably won't be able to rig the correct load to make it draw FLC) measure the voltage drop and calculate what it would be at FLC and see if it is reasonable. Once you have even a small amount of numerical data, the best fault finding strategy might be clear. E.g. unequal currents but equal voltages at the motor terminals points clearly to a winding fault. Unequal voltages points to a supply or switchgear fault.