Understanding Alternate Methods of Motor Starting, an Investigation on Advantages and Disadvantages

When deciding how to safely and reliably start an induction motor, the system designer or system integrator might feel it is only necessary to acquire a motor with sufficient starting torque to accelerate the load. When it is necessary to minimize starting current, most methods of increasing motor starting torque while controlling starting current will cause the motor to absorb more energy during normal operation. Since the cost of energy will well exceed the motor and starter system cost over the life of the motor, this must be considered in the evaluation. Due to operational variations, such as temperature change, voltage, and load fluctuation, the risk of not starting will be high if the torque margin is minimal. If a reduction in starting current is required, this only further magnifies the problem.