High current Solid State Relay 500-1600A

The main differences between Solid State Relays (SSR) and Electromechanical Relays (EMR) lie in their structure and performance. SSRs have no mechanical contacts and use semiconductor devices for switching, offering longer lifespan, faster switching speeds, and noiseless operation, making them suitable for high-frequency operations and harsh environments. EMRs rely on electromagnetic coils to drive mechanical contacts, resulting in slower switching speeds, shorter lifespan, and noise during operation, and they are more sensitive to vibration and shock. SSRs consume less power and are ideal for applications requiring frequent switching, such as heating and motor control, while EMRs are suitable for general switching applications, especially where electrical isolation is needed.

A freewheeling diode, also known as a flyback diode, is connected in parallel with an inductive load (e.g., motor, inductor, or transformer) in electronic circuits to provide a path for the current when the switching device (e.g., transistor, IGBT, or thyristor) turns off. This prevents voltage spikes caused by the inductive load’s stored energy, protecting the circuit and reducing electromagnetic interference (EMI).

A margin should be left when selecting the voltage and current of the solid state relay.

For resistive load: the current is selected according to 2.5~4 times the load current, and the voltage is selected according to 2~2.5 times the load power. Inductive load: current is selected according to 3-7 times load current, voltage is selected according to 2.5-3 times load voltage.

According to the relationship between load current and ambient temperature, when the ambient temperature is high or heat dissipation conditions are not good, the current capacity of the solid state relay should be increased accordingly.
In order to prevent the product from short-circuiting during use, it is necessary to connect a fast circuit breaker or a fast fuse in series with the product in the load circuit.

For inductive loads, a freewheeling diode must be connected to both ends of the load, and a varistor must be connected to the output end (the varistor (MOV) is selected according to 1~1.5 times of the power supply voltage) to prevent the high voltage generated during switching from damaging the solid-state switch.

When the product is installed, it is required that the contact surface between the heatsink and the product must be flat and clean, and a layer of thermally conductive silicone grease is applied to its surface, and then finally the screws set with flat washers and Spring washersare tightened symmetrically to fix.