Liquid resistance starter

[genhead]

Hi all,
A 3.5MW 11,000V motor has a liquid resistance starter. I don't have any more information at the moment, but I'm assuming that it will be driving a crusher or mill. Does anyone know what kind of starting characteristics I can expect. I know that it will vary considerably, depending on the type of load, starter specs etc, but I just need a general idea, e.g. 150% full-load-current, 300% ?
Thanks

 

[waross]

Is this a wound rotor motor?
respectfully

 

[motorspert]

It has have some sort of wound rotor. The beauty of the liquid resistor starter is that you can limit the current right down to 100%, usually 150% is adequate. The actual value depends on the mix of the solution (electrolyte)

The downside is that the energy expended is considerable.

 

[genhead]

Thanks Motorspert,
Can you explain low current but considerable energy expended?

 

[motorspert]

Genhead,
Maybe considerable was a bit of an exaggeration, but the rotor resistance losses can be quite high at high slips, once you have run up to near synchronous slip the resistor loss is very low and often the resistir is shorted out. But the loss during low slip running can be around 10% of input for a pump or fan type drive