Solid Sate Relays have many names such as: SSRs, SCRs, Silicon Rectifiers, Thyristors, Zero Cross Relays and Triac Relays. They all mean the same thing, a non-contact AC switching relay.
Contactors are mechanical devices. After many cycles or use, mechanical devices finally wear out and no longer work. Mercury relays were a great solution in the contactor era. Mercury relays would clean their contacts and last very long periods of time. However anyone who's ever used mercury relays in a high current or long use knows the consequences of a failed relay. Mercury all over the place! Solid state relays are a great solution for both replacing mercury relays and many contactor applications.
The Watlow family of Din-A-Mites & Power Series SCRs can fit any heating system requirement. The Eaton D99 zero cross relays are a great low cost solid state solution.
Call Seagate today for help with your solid state relay requirement.