Ek's Home   |   Forum   |   Chat   |   Electrical Links   |  





Subject - Starting current
Jacob 1.Normally a squirrel cage induction motor, is designed for a maximum starting current of 6-7 times its rated full load current.
What will be the starting current of the same motor, if it is started without any load using DOL starter?

2.Consider the case of a squirrel cage induction motor having a centrifugal pump (water application) as load. Normally before starting the delivery valve of the pump remains closed.
If the pump has a running load of X kW, what will be the starting load (kW) on the motor if it is started with a DOL starter?
JimmyDee
quote:
What will be the starting current of the same motor, if it is started without any load using DOL starter?

I'm not sure what a DOL starter is. In this country we have sever different kinds. Which is closest to it?
Soft start (Electronic)
Auto transformer compensated starter
Cross the line starter
Reduced voltage starter.
And some are using a Variable Frequency Drives for a soft controlled start.
Jim
Kraze Jim I did a Google search on DOL starters it stands for Direct On Line starter just a UK way of saying full voltage starter or Across the line starter

as for the queston whould it not be about 4-5 times Full Load Curent(FLC)
JimmyDee Thanks for that information on the DOL starter. I never have heard of that term.
quote:
What will be the starting current of the same motor, if it is started without any load using DOL starter?

Same as with a load but for a much shorter time frame.
quote:
If the pump has a running load of X kW, what will be the starting load (kW) on the motor if it is started with a DOL starter?

Should be 5-7 times as great as the running load. Of course, this KW draw will decrease as the motor/pump rpm increase to running rpm.
Jim