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11.5kV VFD.

11.5kV VFD.

11.5kV VFD.

(OP)
Dear All.
Im locking for VFD 11.5kV with "bypass". Sorry for term, I meant, after start of motor ( 6MVA) we would like close bypass on VFD and move feeding of motor to another CB.
( reason, used this VFD for another motors)

Firstly, I found, that only Robicon have real 11.5kV VFD, other company used step down-VFD-step up trafo, I would like avoid this configuration.
I know possible provide "bypass" on the VFD 690V, but...for this size of motor... it is joke.

Second, I think about autotransformer start.

What do you recommend in this situation.

Best Regards.
Slava
 

RE: 11.5kV VFD.

If the VFD is only going to be used as a "soft starter" then, have you considered using a solid state soft starter instead of an autotransformer? Solcon makes 11.5kV soft starters. The criteria would be starting torque and available current. A soft starter will reduce the torque and will also require no less than 200% current, usually a 300-400% on typical industrial loads. An autotransformer will be a little lower stress on the line supply because of the transformer action, but in reality it is a stepped transition, so you really just trade one big hit for two smaller ones. If your supply cannot take that kind of abuse, a VFD is the only choice.

In VFDs then, 11.5kV is a good place to consider an LCI drive. They are typically significantly less than a PWM inverter at that voltage and they lend themselves well to bypass use. That is why one of the most common uses of LCI drives is as a giant soft starter, in applications just like you are describing.


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RE: 11.5kV VFD.

(OP)
Dear Jraef.
Many,many thanks for your good tips!!!!!

Best Regards.
Slava

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