First, you've to see the nature of motor starting:

1. Is it started through a variable resistance in the rotor circuit? If so, see how fast is the external resistance brought down to zero. Is it pretty slow, that  we cannot compare it with starting with a shorted rotor?

2. If (1) above is true, then is such a starting needed for the application?

If answers (1) or (2) above are negative, most probably, you could go for an induction motor, with proper ratings.

Narayanan UM
umn@ieee.org

Hi,
I think it will be very useful if you determine what kind a driving application is yours. If your system is using the advantages of slipring (such as soft starting or a limited speed control maybe?), you cannot change your motor directly. High motor starting torques sometimes can break the mechanical system with large inertia. A slipring is a simple way to limit this torque. If you make a change with cage motor you may have to use an additional power electronics soft starter also.
regards

I think you need to tell us more about the application and your electrical
supply.In some cases there is nothing to beat a slipring motor especially
when starting a very heavy load where you want to limit torque and current
draw.My personal experience with them is on rubber mills.

I would suggest the following :


1.please check that your system should be very powerful to sustain starting current of motor.

2. I recomend that you should use atleast 4 stage   auto-transformer method of starting to reduce starting current and smoother running.
The Cage motor can be run,in place of Slipring motor if the above suggestions applied.

Regards
khalid khan