Solid State Contactors
The 'Line Frequency Solid State Switch' is a solid state semiconductor switch designed to switch 480vac power to virtually any type of load. This could be a single phase load or a three phase load depending upon how many poles are included in the switch.
This switch can control power to power transformers, motors, highly inductive loads and parallel resonant loads such as a power factor corrected load. It does this by controlling and limiting the inrush current to both inductive and capacitive loads. The switch always turns off when the line current crosses zero, thereby reducing transients from inductive loads.
The solid state switch can be turned on and off every ten seconds indefinitely. This makes it suitable for duty cycle based power control. This is superior to contactors that have a limited lifetime or number of power cycles due to both the inrush current and the arcing that occurs when the contactor is opened.
The switch can be supplied in one to three poles. It can be purchased on a panel or in a wall mount or floor mount cabinet. The controls available range from simple relay contacts to enable the switch and turn it on and off, to an internal Micrologix PLC with a front panel touchscreen and remote PLC interface. When combined with external temperature sensors, the internal PLC allows this system to be used stand alone for customized process control.