Solid State Relay SSR-25DA, 25A 3-32V DC to AC

Specification

Note:

1. When the load is a resistive load, the maximum load current of the selected SSR should be 2~3 times greater than the actual load current;
   
2. When the load is an inductive load, the maximum load current of the selected SSR should be more than 7~8 times the actual load current.
   
3. When the maximum load current is higher than 10A, a heat sink must be installed to the solid state relay, or the SSR relay should be mounted on a metal base plate with heat dissipation effect, and the thermal grease is applied between them.

Dimension (Unit: mm)

Wiring Diagram

Tips: How to protect solid state relay (SSR)?

1. 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.
2. 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.
3. 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 ℃.
4. 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.