I have a wound rotor motor (200hp) with resistors for starting etc. There are 6 resistors 1 stays in circuit all the time and one is stated to be for braking. This one is the last in the circuit and is jumped across one side to complete the circuit. The problem I have is that the other 4 resistors are not equal steps. There is 1 large step maybe 60% then a 20% a 10% and another 10%. My question is should the 60% be the first step or the last step? The application is a plate roll. We have replaced all the original controls with a PLC. We got this machine in pieces and most of the electrical panel was missing. the original prints do not show different resistors just resistors.

Helllo Daren

Welcome to the forum.

As you alter the rotor resistance, you alter the slip at which maximum torque occurs.
Normally, the final stage resistance is very small so that the motor (at rated torque) is operating close to full speed when the final stage is shorted out. If you have the motor operating at a high slip and step resistance to a very low slip, you will have a very high current step and probably loose torque as well.
I would expect that the 10% resistors are the final resistors and the 60% is the first resistor (applying logic to the sizing)
The 60% would provide high torque at low speed and that is probably required to get the machine going.

Leaving the final stage resistance in circuit will increase the operating slip and slip losses, but will allow for better torque characteristics under transient load conditions.

Best regards,