Power relays are a type of electromechanical switch that are used to control the flow of electrical current within a circuit. They are typically used to control high-voltage and high-current circuits, but can also be used with low-voltage circuits as well.
Both types of power relays are similar in design and function, however, a significant factor that differentiates them is that a latching relay will remain in the last position when it was last powered, whereas a non-latching goes back to its normal position.
When choosing a power relay, it is a universal rule of thumb to take note of a number of specifications to ensure it is fit for the intended purpose.
Whether it is for generator reverse power protection , power windows, directional overcurrent protection and even specific projects such as creating a reliable power control for IoT systems, making a relay controlled power outlet or fixing the Electronic Engine Controls (EEC), there are plenty of factors to consider when handling power relays or other relays.
Listed here are five of the more common ones to review before your purchase:
The required voltage to actuate the switching mechanism is called coil voltage. If a voltage is too high this could damage the power circuits components, if it is too low then the mechanism will not be activated. Power relays are designed to handle high levels of current and voltage, and can be used to switch power to lights and other electrical devices.
There are also instances where a high current flow circuit can be controlled by a low current flow circuit with the addition of 12V power relay switches - an ideal solution for full voltage applications like in vehicle equipment.
This is the neutral state the relay contacts are in without power supply. When the contacts are closed, electricity can flow through the circuit, and when they are open, the flow of electricity is interrupted.
An example is SPST (single pole single throw), where there is one output and one input, and the switch will either be closed or completely disconnected, making it perfect for on-off switching.
Power relay contacts are available in many materials that have certain properties. Common materials are gold, silver, tin oxide and nickel. For instance, materials used for power relay modules must be responsive to an electromagnet while remaining functional and effective even after regular usage.
4. Coil power
Coil power is the amount of power (watts) the coil operates at. This must match the power in the circuit for optimal function, meaning, the chosen power relay must be able to receive its rated coil voltage for standard operational use.
5. Coil resistance
The amount of resistance (ohms) in the circuit that the coil creates. In general a typical and expected value for the coil resistance of a power relay should be between 50 ohms and 200 ohms.
Should you require assistance for your purchase of power relays, or if you wish to know more about other relays available at RS, such as the timer relays or reed relays, do contact us for more information. Browse RS online site for a wide selection of components such as fan filters, trace heating cables and more that are of excellent quality and functional