WRIM Resistor Grid

In a WRIM, the speed is not directly controlled by the resistance at all, only the torque is. The reduction in torque effectively reduces the speed, and because you can control the rotor current you can control the speed somewhat.

While it is true that you will get maximum torque from that motor with zero resistance in the rotor, you cannot actually use that for starting, because the current drawn by the rotor will be so high that it will likely damage it. The trick is to find the optimum amount of resistance that provides sufficient starting torque with the least amount of current. There is a forumla for determining that optimal rotor resistance needed for starting, but it is complex. There is a simple share-ware program that will do it for you however, you can read about it here.

Thanks for the link!!!!!

Reset the "grid" ohmages per the resultant values of the calculator and OMG!! this just may work! Testing throughout the holidays.

Happy Holidays All!!!