Understanding how to wire a 5 wire relay can seem daunting at first, but with the right explanation, it becomes much clearer. A 5 wire relay wiring diagram is your roadmap for safely and effectively controlling electrical circuits with a low-current signal. These relays are fundamental in automotive applications and beyond, acting as electrical switches that allow a small voltage to control a much larger one.
The Ins and Outs of a 5 Wire Relay
A 5 wire relay is essentially an electromagnetically operated switch. It has five key terminals that dictate its function. Two terminals are for the coil, which is the electromagnet. When you apply power to these coil terminals, the electromagnet energizes and pulls a movable contact, closing or opening another set of contacts. The remaining three terminals are the switch contacts themselves. This setup allows a low-power signal, like one from a dashboard switch, to control a high-power device, such as headlights or a starter motor, without the high-power circuit directly interacting with the low-power control circuit.
The typical 5 wire relay configuration includes:
- Terminals 30 and 87: These are the power input and output terminals for the load.
- Terminals 85 and 86: These are the coil terminals. Applying voltage to these energizes the relay.
- Terminal 87a (normally closed): This terminal is connected to terminal 30 when the relay is not energized.
The beauty of the 5 wire relay lies in its versatility. It can be used to switch a device ON or OFF, or to direct power from one circuit to another. For instance, in a car, a 5 wire relay can be used to power a fan only when the engine is running, or to activate fog lights only when the headlights are on. The importance of using a 5 wire relay wiring diagram correctly cannot be overstated, as it ensures proper function and prevents damage to your electrical system.
Here's a breakdown of a common use case:
| Terminal | Purpose | When Energized | When De-energized |
|---|---|---|---|
| 85 | Coil Ground | Connected to 86 | Disconnected |
| 86 | Coil Power | Connected to 85 | Disconnected |
| 30 | Power Input | Connected to 87 | Connected to 87a |
| 87 | Normally Open Output | Connected to 30 | Disconnected |
| 87a | Normally Closed Output | Disconnected | Connected to 30 |
When you are working on projects that require controlling higher amperage circuits with a lower amperage signal, understanding a 5 wire relay wiring diagram is crucial. To get a clear visual and practical understanding, refer to the diagrams provided in your specific application's manual or consult automotive electrical guides.