Relays are devices used to control high voltage and current devices from low voltage and current control signals. They offer numerous advantages such as isolation, noise reduction and voltage level shifting. In this article, we will discuss the DPDT (Double pole double throw) relay wiring diagram, which is commonly used in several industrial and residential applications.
What is a DPDT Relay?
A DPDT relay is a type of relay that has two poles and two throws. The two poles mean that it has two separate circuits and the two throws mean that it has two different positions. The DPDT relay switches between two different circuits, making it a very useful device in many applications.
DPDT relays are often used to switch between two power sources, to control a motor in forward and reverse directions, or to isolate sensitive circuits from noisy or high voltage circuits. They are commonly used in HVAC, lighting control, security systems, and machine control systems.
DPDT Relay Wiring Diagram
The DPDT relay wiring diagram shows the relay poles and throws, the coil, and the terminals used to connect them. The diagram also shows the connections for the normally open (NO) and normally closed (NC) contacts.
A DPDT relay has six terminals, which are labeled as follows:
- Coil-1
- Coil-2
- NO-1
- NC-1
- NO-2
- NC-2
The following is the wiring diagram for a DPDT relay:
| Terminal | Function |
|---|---|
| Coil-1 | Connect to positive voltage |
| Coil-2 | Connect to negative voltage |
| NO-1 | Connect to load circuit 1 |
| NC-1 | Connect to load circuit 2 |
| NO-2 | Connect to load circuit 1 |
| NC-2 | Connect to load circuit 2 |
How to Wire a DPDT Relay
Wiring a DPDT relay is relatively easy, and it can be done in a few simple steps:
- Identify the six terminals of the DPDT relay and their functions, as shown in the wiring diagram above.
- Connect one end of the load circuit 1 to the NO-1 terminal, and the other end to a power source.
- Connect one end of the load circuit 2 to the NC-1 terminal, and the other end to a power source.
- Connect one end of the coil-1 to the positive voltage source, and the other end to the NO-2 terminal.
- Connect one end of the coil-2 to the negative voltage source, and the other end to the NC-2 terminal.
When the coil is energized, the contacts on the NO side will close, and the contacts on the NC side will open. When the coil is de-energized, the contacts on the NO side will open, and the contacts on the NC side will close, making it a versatile device for controlling multiple circuits.
FAQs
What is the difference between NO and NC contacts on a DPDT relay?
The NO (Normally Open) contacts on a DPDT relay are open when the coil is not energized and will close when the coil is energized. The NC (Normally Closed) contacts are closed when the coil is not energized and will open when the coil is energized.
Can a DPDT relay be used to switch between AC and DC circuits?
Yes, a DPDT relay can be used to switch between AC and DC circuits. However, it is important to select a relay that is rated for the voltage and current of both circuits.
How do I know which terminals are the NO and NC contacts on a DPDT relay?
The NO and NC contacts are labeled on the DPDT relay. The NO contacts are usually labeled as NO-1 and NO-2, while the NC contacts are labeled as NC-1 and NC-2.
What is the purpose of a DPDT relay?
The purpose of a DPDT relay is to switch between two different circuits, allowing for multiple functions to be controlled by a single device. It is used in a variety of applications, including HVAC, lighting control, security systems, and machine control systems.
What is the maximum current rating for a DPDT relay?
The maximum current rating for a DPDT relay depends on the specific model and manufacturer. It is important to select a relay that is rated for the voltage and current of the specific application.
In conclusion, a DPDT relay is a versatile device that can be used in various industrial and residential applications. Understanding the wiring diagram and how to wire a DPDT relay is crucial to ensure proper functioning of the device. With this knowledge, you can easily incorporate this device into your projects and make your circuits more efficient.
