50 A Solid State Relays (SSR)

50 A Solid State Relays (SSR) prices and range: 12 models with current prices, stock status and specifications at Welibaba. A solid state relay (SSR, semiconductor relay) is a contactless relay that switches the load with semiconductor elements such as a triac, thyristor or transistor instead of a mechanical contact. Because it has no moving parts, it operates silently and has no contact wear; for this reason it is used on loads that switch on and off frequently, such as resistive heaters and ovens. This category includes single-phase and three-phase relays with load currents such as 25 A, 40 A and 100 A and 3-32 V DC or AC control, and analog models with 4-20 mA, 0-10 V or potentiometer input, from the brands Isıso, Enda, Siemens and Soljex. Select the SSR according to the load type (AC or DC, resistive or inductive), the load current and voltage, the control signal, the number of phases, and whether you need zero-crossing or analog-input operation. The rated current is given for a specific cooling condition; check whether a heat sink is included and the manufacturer's current-temperature curve. An SSR should not be confused with a contactor or an electromechanical relay: it passes a leakage current even when off and does not physically isolate the circuit, and models with AC outputs cannot switch off a DC load.

Solid State Relays (SSR) Selection Guide: Technical Criteria and Engineering Practice