The ST1A controller is designed to provide a soft start for electric motors operating at 500V or 1000V within WROT-series equipment. Through the use of specialized modules, operation at voltages of up to 6kV is also possible. The controller allows for an adjustable start-up time (from 0 to 30 seconds) and an adjustable starting torque (from 0% to 100%). It is also responsible for monitoring the temperature of the thyristors. In conjunction with a thyristor monitoring relay, it shuts down the device if the operating temperature of the thyristors exceeds 70°C. The controller indicates when the equipment is ready for start-up and, in coordination with a start-up module, initiates the soft-start sequence. The ST1A controller is housed in an enclosure with an IP20 ingress protection rating. Signals are routed via a rectangular AMP connector, with the option for adjustable cable lengths.