Solid State Relay Heater Control Circuit

This article provides an introduction to the basic operation of solid state relays with a focus on the output devices in today s ssrs.

Solid state relay heater control circuit. Ssr s usually fail in the on state so for safety a two pole electro mechanical contactor should be in the heater circuit which is controlled by a latching over temperature controller. Unlike emr electromagnetic relay that has a coil mechanical switch physical contacts the ssr relay uses optocoupler to isolate the control circuit from the controlled. High power solid state relays g3ph high power load control ssrs with high current of 75 or 150 a and high voltage of 240 or 480 vac solid state relays with built in current transformer g3pf. These solid state relays are compact to save space and have a mounting foot that can snap onto a mounting rail or be screwed onto mounting plates.

A solid state relay ssr is an electronic switching device that switches on or off when an external voltage ac or dc is applied across its control terminals. Ssrs consist of a sensor which responds to an appropriate input control signal a solid state electronic switching device which switches power to the load circuitry and a coupling mechanism to enable the control signal to activate. To commutate the inductive load with a solid state relay you should increase the current reserve by 6 8 times. There are many circumstances in which we need to control a high current voltage load based on the operation of a low power circuit such as when using the 5v output of a microcontroller to turn on a 10a 240v load.

Since the 4 20ma or 0 10vdc control input of the analog relay can be varied the output operates in accordance with the phase control principle. Solid state relay ssr is an electronic switching device made of semiconductors that switch on off a high voltage circuit using a low voltage at its control terminals. An ssr is preferred for the normal quick cycling of the heater for temperature control. Siemens solid state relays include a heat sink that allows power to dissipate into the ambient air to maintain a safe temperature.

The solid state relay circuit consists of. Control systems devices of solid state relay motor pump welding machine transformer or heater. Oscar montero r d manager and doug sherman fsae manager crydom inc. I put the cover on the unit after.

Three phase solid state relays ssrs have been available since shortly after the introduction of single phase ssrs in 1970. The principle of operation of a solid state relay is the closing or opening of contacts. I found some high current solid state relays and used one to control the electric heater at home with a digital thermostat. This a is a legal requirement for industrial ovens in the u s.

The output is proportional to the input signal.