Solid State Relay Features
25A solid state relay (SSR), 3-32V DC input and 24-480V AC output, features compact size, high structural strength, good impact resistance, and strong shock resistance. The SSR offers a reliable switching the commercial and industrial loads, such as computer peripheral interface device, printing machine, molding machine, food machine, packaging machine, and so on.
- Built in RC absorption
- Photoelectric isolation
- SCR output
- LED indicator for operation status
- Removable protective cover for safety
- Panel mount
- Zero-crossing switch type
25 Amps DC to AC SSR Specification
||Control voltage range
|Max. input current
|Must operate voltage
|Must release voltage
||Load voltage range
|Maximum off-state leakage current
|Maximum off-state time
|Maximum on-state voltage drop
||Dimension L – W – H (mm)
|Dielectric strength (input to output)
|Dielectric strength (input, output to the base)
* When the load current is higher than 10A, a heat sink must be added to the SSR or the SSR should be mounted on a metal base plate with heat dissipation effect, and apply the thermal grease between them. When the load current is higher than is 40A or more, fan forced cooling or water cooling is needed.
* Heat sink is Not included.
Solid State Relay Dimensions
SSR Wiring Diagram
Tips: How to protect solid state relay (SSR)?
- Overcurrent protection
SSR is a semiconductor power device that is extremely sensitive to temperature changes. Overcurrent may cause damages to it. Therefore, a fast acting fuse is usually used. But it is necessary to understand its protection features, to know the relationship between fuse current and time, and to correctly choose the fast acting fuse compatible with nominal current of SSR.
- RC absorption circuit
RC absorption circuit. The use of RC circuit not only prevents over-voltage, but also improves dv/dt. The recommended R is 20-100Ω, the power 2-5W, C 0.1-0.47uf, and the withstand voltage is 250-630V. If SSR has lower nominal current, R adopts its upper limit 100Ω and C adopts its lower limit 0.1uf. Otherwise, R adopts its lower limit and adopts its upper limit.
- Overheat protection
Overheated SSRs' characteristics may compromise, ranging from the loss of control to permanent damage. It is recommended to install a temperature control switch near the SSR baseplate with temperature control point at 75 to 80 ℃.
- Series inductance L in inductor load
In the inductive load, SSR is usually damaged due to high rate of current di/dt. The inductance value of L depends on the size and cost level.