Contactor and Relay

A contactor and a relay are both electrical devices used to control the flow of electricity in a circuit, but they serve different purposes and are designed for different applications. If you’re looking for a manual way to turn off the electricity flow, go to our switch category.  The information below will discuss the difference between contactors and relays.

Contactor: A contactor is a heavy-duty electrical switch used to control the power supply to large electrical loads, such as motors and heaters in your electric vehicle conversion. It consists of a set of contacts that open and close to allow or interrupt the flow of electrical current. Contactors are used for high-current and/or high-voltage scenarios. There are many types of contactors used in electric vehicles.

Some factors to consider for contactors :

• Large Current Capacity: Contactors are designed to handle high current loads, making them suitable for controlling powerful electrical devices.

• Durability: Contactors are built to withstand frequent use and the wear and tear associated with switching heavy loads.

• Remote Control: Many contactors can be controlled remotely, allowing for automation and integration into larger control systems.

• Magnetic Coil: Contactors typically include a magnetic coil that, when energized, causes the contacts to close, allowing current to flow. This current voltage is typically provided by your 12 V system in electric vehicle conversions when running high-voltage battery packs. If you're doing a low-voltage such as 48 V as you see in golf carts typically, the cell voltage could be the same source as your battery.

Relay: A relay is a smaller, versatile electrical switch used to control lower-power circuits. It consists of an electromagnet, a set of contacts, and a spring. Relays are often employed to control one circuit using a signal from another circuit. They are commonly used in applications where a low-power control signal is used to switch a higher-power load. A place you will see a relay in an electric vehicle conversion is in the pre-charge system. When allowing power to pass through a resistor slowly increase the voltage on the main high voltage contactor during the start-up procedure. This prevents a large amount of current going to electronics at once, increasing the lifespan of the components.

Some factors to consider for relays are:

• Low-Power Switching: Relays are designed for low-power control, making them suitable for applications where a small control signal needs to switch a larger load.

• Versatility: Relays come in various types and configurations, allowing for a wide range of applications in both industrial and residential settings.

• Isolation: Relays provide electrical isolation between the control circuit and the load circuit, preventing interference and protecting sensitive components.

• Signal-Switching Capability: Relays can be triggered by a variety of input signals, such as voltage or current, and are commonly used in automation and control systems.