Relays have been around for a long time, serving as switches for various electrical circuits. A 7 pin relay is an incredibly useful component in both automotive and industrial settings, where it can be used to control and protect a wide range of electrical devices. However, wiring a 7 pin relay can be challenging, especially for those who are unfamiliar with electrical systems. In this article, we will provide you with a comprehensive guide on how to wire a 7 pin relay and the different ways it can be used.
What Is a 7 Pin Relay?
A 7 pin relay is a type of electromechanical switch that consists of seven terminals, including a common terminal, a normally closed (NC) terminal, and five normally open (NO) terminals. The relay is typically used to control high current devices or circuits that would be difficult to control directly with a switch or other device.
The 7 pin relay works by using a small amount of current to activate an electromagnet, which in turn closes or opens the switch contacts. This allows a low voltage control circuit to control a high voltage circuit, which can be used for a wide range of applications.
The 7 Pin Relay Wiring Diagram
Wiring a 7 pin relay requires an understanding of the wiring diagram, which shows the proper connections between the various terminals. The wiring diagram is typically printed on the relay itself, but it can also be found online or in a relay wiring diagram guide.
The 7 pin relay wiring diagram is simple to follow, as it consists of just a few basic connections:
| Terminal Number | Description |
|---|---|
| 85 | This terminal is used to connect the relay coil to ground. This provides a return path for the current flowing through the coil. |
| 86 | This terminal is used to connect the relay coil to the power source. This provides the current needed to energize the coil and close the switch contacts. |
| 87 | This terminal is used to connect the high current device or circuit that is being controlled by the relay. |
| 87a | This terminal is used when a normally closed (NC) contact is required. It provides a second contact that is normally closed when the relay is not energized, and opens when the relay is energized. |
| 30 | This terminal is used to connect the power source to the relay switch contacts. It provides the power needed to operate the device or circuit that is being controlled by the relay. |
For a better understanding, you can check the following wiring diagram:
How to Wire a 7 Pin Relay
Wiring a 7 pin relay is a relatively simple process, but it is important to follow the correct steps to ensure that the relay is wired correctly:
Step 1: Select the Appropriate Relay
The first step in wiring a 7 pin relay is to select the appropriate relay for your application. This will depend on the voltage and current requirements of the device or circuit that you want to control.
When selecting a relay, you should consider factors such as the voltage and current requirements of the device, the maximum current rating of the relay contacts, and the type of contacts that you need (normally open or normally closed).
Step 2: Connect the Power Source
The next step is to connect the power source to the relay coil. This is done by connecting the positive (+) terminal of the power source to terminal 86 and the negative (-) terminal to terminal 85. This will provide the current needed to energize the relay coil.
Step 3: Connect the Load
The load is the device or circuit that is being controlled by the relay. To connect the load, you need to connect the positive (+) wire from the load to terminal 87 and the negative (-) wire to either terminal 87a (if a normally closed contact is required) or terminal 30 (if a normally open contact is required).
Step 4: Test the Connection
After wiring the relay, it is important to test the connection to ensure that everything is working correctly. You can do this by applying power to the relay and checking that the switch contacts are opening and closing as expected.
FAQs
What is a 7 pin relay used for?
A 7 pin relay is typically used to control high current devices or circuits that would be difficult to control directly with a switch or other device. It can be used in automotive and industrial settings to control a wide range of electrical devices.
How do I know if my relay is bad?
If your relay is not working properly, you may notice that the device or circuit that it is controlling is not working as expected. You may also hear clicking or buzzing sounds coming from the relay. To test the relay, you can use a multimeter to check the resistance across the coil terminals and the switch contacts.
Can I wire a 7 pin relay to control multiple devices or circuits?
Yes, you can wire a 7 pin relay to control multiple devices or circuits, but you need to make sure that the relay is rated for the total voltage and current requirements of all the devices or circuits that you want to control.
What is the difference between a normally open and normally closed contact?
A normally open contact is a switch contact that is open (not connected) when the relay is not energized, and closes (connects) when the relay is energized. A normally closed contact is a switch contact that is closed (connected) when the relay is not energized, and opens (disconnects) when the relay is energized.
What is the maximum current rating of a 7 pin relay?
The maximum current rating of a 7 pin relay depends on the specific model and manufacturer, but it can typically range from a few amps to several hundred amps.
Conclusion
Wiring a 7 pin relay can be a simple process if you follow the correct steps and have a basic understanding of electrical systems. By using a 7 pin relay, you can control high current devices or circuits that would be difficult to control directly with a switch or other device. If you have any questions or concerns about wiring a 7 pin relay, consult the wiring diagram or seek the advice of a qualified electrician or technician.
