Using Inverter with exsiting slip-ring motor for overhead crane 2

[Banphot]

Hello:

In our steel making plant factory, there is an electric overhead crane with 120 ton hoist driven by 220KW slip-ring motor. The motor is started using 4 steps of rotor resistors, and speed is controlled via SCR circuit.

We would like to install vfd inverter to control speed instead of existing SCR, and utilize the existing slip-ring motor by short rotor circuit at its slip-ring. Could anybody suggest the disadvantage or risk of doing this? Is there any experience of doing this with heavy steel mill crane application?

Thanks in advance.

Banphot

 

[Skogsgurra]

I agree, Roy. You highlighted quite a few crucial things that seldom are discussed. Real useful.

I would never use a TTL output in a VFD environment. The rule is to use 12, 15 or 24 V signals. Filtered inputs and/or differential signalling (A and /A plus B and /B).

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[roydm]

Skogs,
I guess TTL was the wrong term to use, what I meant was signal driven in both directions to give a nice square wave.
Roy