Solid State Relay, 3 phase, load current 40A, AC-AC, with LED indicator, zero-crossing switch, built-in RC, optical isolation, no electric spark, no noise, no contact, high switching speed, high reliability, long lifespan, wide applications.
|On-state voltage drop
|Off-state leakage current
||2500V AC (1min)
||500МΩ with 500V DC
||Heat sink or fan needed for cooling
Tips: SSRs’ over-current protection
SSRs take semiconductor switching devices as power output components, and are sensitive to temperature changes. Over-current may overheat semiconductor chips, which results in there decreased quality, life expectancy reduction or even permanent damage. Although SSRs in an instant can withstand surge current 10 times larger than the rated current, but permanent damages are likely to be caused if the current is more than such a value. Therefore, over-current protection is very important. There are many ways for over-current protection. The key is to fast response. For AC SSR with SCR as output devices, general protection circuits are invalid due to current zero required by SCR’s turn-off if the surge current and short-circuit current are larger than SSR’s surge current within 10 Ms (50Hz). At this moment, fast acting fuses exclusive for semiconductor devices. Fuses’ nominal fusing current should not exceed the nominal current value of the SSR. There are a variety of commercial fuses, but their quality is different. Therefore, pay attention when choosing fuses.