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Liquid stater

Liquid stater

Liquid stater

(OP)
Good day,

I need some guidance from forum members.A steam turbine driving a rock crusher failed yesterday on site and we are now contemplating to install one 1000 kW 5,5 kV 50 Hz to drive the load.The motor is available on site and the open circuit rotor voltage is 891 V and the rotor current is 679 A.The electrolytic starter available is rated 1200 V and 585 A.
I am guessing that the short circuit contactor is limited to a maximum of 585 A.Am I right, as the electrolytic stater is only used to start the load.A possible solution is to replace the contactor by a higher rated one.

Thanks for comments.

Guardiano
 

RE: Liquid stater

It depends.
In some plants I would expect the starter to be installed and the shorting breaker to be changed out to a larger size when possible.
In other plants a new contactor would be fitted before the starter was put in service.
In a plant over run by MBAs insurance requirements and regulations, the available starter would not be used, a new starter of the appropriate rating would have to be obtained.
If you are starting the crusher unloaded as I expect that you are, you may be able to set the timing on the liquid rheostat so that the starting current does not exceed 585 amps. Check with the manufacturer, the rheostat may be suitable for more current than the contactor.  

Bill
--------------------
"Why not the best?"
Jimmy Carter

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