sizing a generator

Hi, We are upgrading our generator (ac 3 phase). However it is 110 KW and we wish to use a bow thruster (start delta starting) which has a motor of 80 kw.

Do you think that the generator will handle the start up current ?


Thanks
Neville

 

Who knows? That's why God created electrical engineers.

 

If the motor is 80Kw maximum power, yes. Otherwise, the specifications will tell you what the required starting power is. Also, check what the continuous rating for the generator is.

 

The thruster's fuse recommendation is one clue. Different gensets have widely varying abilities to surge on starting loads and the rest of your electrical system will need to be tolerant of the fluctuations. Soft starters would be one option.

 

I would think a good thing to know is how much power is being drawn off the generator right now, so when the new generator goes in, you know how much can be dedicated to the thruster.

That being said, to this day nobody has ever paid for my opinion.
I can tell you that we use larger generators than that at work, and a 30 hp electric motor will cause a surge and bog down for a split second while they start.

 

If you have a clamp on meter, you can check the starting current of the bow thruster and compare this with the overload capacity of the generator. Depending on the motor, some have up to 800% starting current and this surge is taken by the overload capacity and time delay breaker of the generator.

This might help in calculations.
http://powertips-elec.blogspot.com/2010/11/motor-starting-and-running-currents-and.html