Motor starting time

[SELEC]

I am doing a dynamic motor starting study for 5000HP motor using ETAP.

Based on motor data,load data, motor innertia(1130),coupling inertia(25), load inertia(78), the starting time is only 3seconds. Based on my experience, it should be at least 5s. is there something wrong with my inputs? Or maybe the load inertia( I assumed ) is too low.

 

[jraef]

Load inertia seems a tad low, but what is it, a pump? Direct drive grinding wheel? Rotary fly swatter? And are you considering load torque, not just inertia?

Also, did you consider it an infinite bus? Voltage drop will affect starting time.

Eng-Tips: Help for your job, not for your homework Read faq731-376

 

[Skogsgurra]

That is hard to tell if we do not know all your input data. My first guess is that you assume infinite grid. There can be any other reason - from "sqrt(3)" to typo.

Gunnar Englund

http://www.gke.org

 

[jraef]

Great minds think alike Gunnar.


As do occasionally inebriated minds like ours eh?!

Eng-Tips: Help for your job, not for your homework Read faq731-376

 

[SELEC]

It is 2 pole motor.