A Soft Start motor is a type of AC (Alternative Current) electric motor controller that temporarily reduces the load and torque (rotational force) on the motor during start-up, to prevent electrical current surges. This is especially important with large horsepower motors, that require a lot of power to get started. This type electric motor start-up also reduces the mechanical stress on the motor and shaft, as well as the electrodynamic stresses on the attached power cables and electrical distribution network, extending the lifespan of the control system.
Peterson electric chippers and grinders can be controlled with either soft starts of VFD (variable frequency drives). Soft starts are the most economical however they are limited to one speed and can result in high short term peak current loads. If electric energy is paid including a load factor for peak energy demand, the monthly bill may be very high because of the peak loads.
Peterson electric machines with a 100HP electric motor running a hydraulic system is controlled with a soft start(er).