Is a solid state relay an inductive load?
An SSR used with an inductive load can accidentally fire due to a high load voltage rise rate (dv/dt), even though the load voltage is below the allowable level (inductive load firing). Our SSRs contain a snubber circuit designed to reduce dv/dt (except AQ-H).
Do solid-state relays need a load?
Solid State Relay Output Waveform With no input signal applied, no load current flows through the SSR as it is effectively OFF (open-circuited) and the output terminals see the full AC supply voltage.
What is the load current handled by the solid state relay?
Power MOS FET Solid-state Relays do not require a holding current, and feature small leakage currents. The minimum load current required for Power MOS FET Solid-state Relays to operate normally at 200 VAC is 100 µA.
How much current does a solid state relay draw?
Packaged solid-state relays use power semiconductor devices such as thyristors and transistors, to switch currents up to around a hundred amperes. Solid-state relays have fast switching speeds compared with electromechanical relays, and have no physical contacts to wear out.
Are solid state relays NO or NC?
The standard SSR has a single normally open (NO) output arrangement. However, there are many applications which need the opposite, a normally closed (NC) configuration, with the output stage opening when power is applied to the input stage.
Does SSR fail closed?
Might be good to have this as an additional failsafe (because it isn’t dependent on the microcontroller). SSRs more often fail closed. So it is a real concern and you should anticipate it and where possible include a mechanical relay, contactor, or breaker that shuts off the load if and when the SSR fails closed.
How many amps can a solid state relay handle?
SSRs allow the switching of large loads via ultra-sensitive input power. A low level logic signal (TTL) can activate a switch for as much as 100 Amps. Completely quiet switching, beneficial in medical applications, environmental controls or other areas where quiet operation is desirable.
How many types of solid state relays are there?
three different types
Solid state relay switches can be classified into three different types or “forms”, based on the pole and throw information above. Form A switches are SPST (single pole, single throw) and normally open (NO). Form B switches are SPST and normally closed (NC).