slip ring motor Starter-buffer for peek load

[Guest]

Why Buffer Resistance to be add permanently in s.r. motor rotor ckt?

Can We Use Inductance Wond On Un- Saturable Core be used as buffer? how the s.r motor will perform if we connect inductanc permanetly in rotor ckt during running? how for it is advisable?

[RalphChristie]

I am not aware of putting a resistor permanently in a woundmotor's rotor circuit. Normally the rotor is shorted after it comes to fullspeed.

In some instanances they use resistors for a kind of speed-control, but by changing the resistance, the change the motorspeed.

 

There is some interesting cases where resistors are add permanently into the circuit. It is where two or more woundmotors are working together to turn something. Check www.eng-tips.com

 

http://www.eng-tips.com/viewthread.cfm?qid=41223

 

See especially the comments of Mark - very good.

 

Regards

Ralph;d;

[jraef]

Actually, changing resistance in a wound rotor motor changes the torque, not the speed, but with less torque on the same load, speed usually drops as a result. Your application might have been trimmed to run at a torque value less than that available with the rotor fully shorted. I would not change that without knowing why. Mechanical damage may be the result.