The SSR240D series is no longer available please see the SSRL240
and SSRL660 Series as a possible alternative.
An OMEGA™ Solid State Relay (SSR) is a single-pole, normally open switching device without moving parts, capable of millions of cycles of operation. By applying a control signal, the SSR switches “ON” the ac load current, just as moving contacts do on a mechanical contactor.
"Switching" takes place at the zero voltage crossover point of the alternating current cycle. Because of this, no appreciable electrical noise is generated. OMEGA’s “SSR” Series is a twin SCR type, which is inherently more reliable and will handle higher overloads before failure than triacs. Heat is developed in a Solid State Relay due to the nominal voltage drop across the switching device. To dissipate the heat, an SSR must be mounted vertically on a finned heat sink or an aluminum plate. An SSR should be located where the ambient temperature is relatively low, since the current switching rating is lowered as temperature increases. Refer to the thermal derating curves shown below to determine the proper heat sink required.
Solid State Relay cycle life is many times that of an equivalently priced mechanical contactor. OMEGA recommends Solid State Relays for use with proportional temperature controllers and other applications where long life and solid state reliability are needed.
In contrasting Solid State Relays with mechanical contactors, it should be noted that a Solid State Relay is more prone to failure due to overload and improper initial wiring. Solid State Relays can fail with contact closed on overloaded circuits.
OMEGA™ finned heat sinks (FHS) are aluminum fabrications and come complete with tapped mounting holes and screws. Refer to thermal derating curves for heat sink election.
For complete product specifications see the Related Links section at the bottom of this page.
