Solid state relay, 3 phase, SSR-25AA, 25A 70-280V AC to AC

Solid State Relay, 3 phase, load current 25A, AC-AC, equipped with LED indicator, zero-crossing switch, built-in RC, optical isolation, high reliabilty, long lifespan and wide application.

Specification

Dimensions

Wiring diagram

Tips: The advantages of SSRs over AC contactors

1. In the first place, SSRs have a long life and high reliability. SSRs do not have mechanical components, and use solid state devices to complete the contact function. Because there is no movement of those components, they can work in an environment full of high impact and vibration. Inherent characteristics of SSRs’ components determine their long life and high reliability. However, poor contact failure and then burned contactors may be caused by coils which are used by AC contactors to control magnetic drawing for the purpose of contacts’ connection or disconnection.
2. SSRs have good sensitivity, low control power and good electromagnetic compatibility. The SSR has a wide input voltage range and low drive power, which makes it compatible with most logic integrated circuits without a buffer or driver.
3. SSRs have fast conversion. Because SSRs adopt solid state components, their switching speed can be from a few milliseconds to a few microseconds, and the conversion speed is very fast; and AC contactors’ drawing is controlled through coils, so the conversion speed is a few tenths of seconds, slow relative to SSRs.
4. SSRs have small electromagnetic interference. Because there is no input coil in SSRs, no contact striking and bound, electromagnetic interference is reduced. Most AC-output SSRs are zero-voltage switches that turn on at zero voltage and turn off at zero current, which reduces sudden interruption of the current waveform and thus reduce switching transient effects. However, the contactor’s electromagnetic interference is larger.
5. SSRs are small while contactors are large in volume. It is not convenient for contactors to be installed in some relatively narrow space while SSRs may come in convenient. Nevertheless, SSRs do not have that large current generally, but contactors do.
6. SSRs can have various voltage conversions, such as AC to AC, AC to DC, DC to DC, etc. Contactors can not be so flexible.