Last Updated on October 23, 2023 by Kevin Chen
DPDT image source Elprocus
A DPDT relay is a type of electrical switch that is used to control two separate circuits using only one switch.
It stands for Double Pole Double Throw, which means that it has two sets of contacts that can be switched between two different positions.
This type of relay is commonly used in applications such as motor control, lighting control, and other applications where two circuits need to be switched on and off.
It is also used in many industrial applications such as HVAC systems, pumps, and other machinery.
In this article, we are going to dig deeper into DPDT relays and what you should know before buying one.
What is a relay?
Before we get into the specifics of a DPDT relay, let’s first discuss what a relay is. A relay is an electrical switch that is used to control one or more circuits using only one switch. It works by using an electromagnet to open and close the contacts of the switch, hence closing and opening the circuit.
How does DPDT work?
The working mechanism of a DPDT relay is quite simple. It has two sets of contacts, one for each circuit.
When the switch is in the “on” position, both circuits are closed and current can flow through them. When the switch is in the “off” position, both circuits are open and no current can flow through them.
Unlike the normal switch that will remain on or off unless you physically switch it, the DPDT is quite different. The presence of the magnetic field makes the whole difference. How? Well, When the switch is in the “on” position, the magnetic field will attract the armature and close both circuits.
When the switch is in the “off” position, the magnetic field will repel the armature and open both circuits.
Also, the fact that it is a double throw means that it can be used to control two separate circuits. This makes it ideal for applications where two circuits need to be switched on and off at the same time.
DPDT image source Moniteur devices
In this context, configuration refers to the way the contacts of the relay are wired. The most common configuration for a DPDT relay is to have two sets of contacts, one for each circuit.
The contacts can be wired in either a normally open (NO) or normally closed (NC) configuration. In a normally open configuration, the contacts are open when the switch is in the “off” position and closed when the switch is in the “on” position. In a normally closed configuration, the contacts are closed when the switch is in the “off” position and open when the switch is in the “on” position.
How do I identify a DPDT relay?
Since there are other types of relays, you need to be careful when it comes to identifying a DPDT. A DPDT has a solenoid that is properly wrapped in a coil. It also has two sets of contacts, one for each circuit.
The contacts can be wired in either a normally open or normally closed configuration.
In terms of design and size, DPDT relays are usually larger than other types of relays. They also have a higher current rating, which means they can handle more power.
Advantages of DPDT
Not sure of the benefits that you will gain from incorporating DPDT into your circuit? Well, here are the top advantages.
-Relays two independent signals: As we have discussed about the configuration, DPDT has two poles each carrying two independent signals.
-High current rating: DPDT relays have a higher current rating than other types of relays, which means they can handle more power.
-Easy to install: They are easy to install and require minimal wiring. You can easily handle a DPDT project without facing any major hurdles.
-Cost effective: These relays are relatively inexpensive compared to other types of relays.And you can easily get affordable DPDTs from reputable suppliers
-Less weight: DPDT relays are usually smaller and lighter than other types of relays, which makes them easier to transport and install.Their lightweight nature also makes them ideal for weight-sensitive applications.
-Failover capabilities: Failover refers to the ability of a system to switch from one circuit to another in the event of a power failure. DPDT relays are ideal for applications that require failover capabilities.
-Wide range of applications: There is no doubt that DPDT relays are versatile and can be used in a wide range of applications. From motor control to lighting control, these relays can be used in almost any application.
Despite their numerous advantages, DPDT also have some limitations including: -Affected by network connectivity: These relays are affected by network connectivity and can be unreliable in certain situations.
-Difficult to switch broadcast traffic: It can be difficult to switch broadcast traffic between two circuits using a DPDT relay.
Applications of DPDT
Here are the major uses of DPDT relays and the role that they play.
-DC motor control circuit: Here, the DPDT relay is used to control the speed and direction of a DC motor. It can be used to switch between two different speeds or directions.
-Lighting control circuit: The DPDT relay can be used to control the lighting in a room or building. It can be used to switch between two different lighting levels or to turn the lights on and off.
-HVAC systems: The DPDT relay can be used to control the temperature in a room or building. It can be used to switch between two different temperatures or to turn the system on and off.
-Pumps: The DPDT relay can be used to control the flow of water in a pump. It can be used to switch between two different flow rates or to turn the pump on and off. -Other industrial applications: The DPDT relay can be used in a variety of other industrial applications such as conveyor systems, machine tools, and more.
How do I connect DPDT relay in a circuit?
A double pole double throw relay comes with eight terminal points that need to be connected in order for it to work properly. The terminals are labeled as follows: -COM: Common terminal, used to connect the common point of the two circuits.
-NO1 and NC1: Normally open and normally closed terminals for the first circuit.
-NO2 and NC2: Normally open and normally closed terminals for the second circuit. -COIL1 and COIL2: Coil terminals, used to connect the relay coil to a power source.
To connect the DPDT relay in a circuit, you will need to connect the common terminal to the common point of the two circuits.
Then, connect the normally open and normally closed terminals of each circuit to their respective points. Finally, connect the coil terminals to a power source.
What is the difference between DPD and SPDT relays?
Both are relays used to control electrical circuits. A DPDT (Double Pole Double Throw) relay has two sets of contacts that can be switched between two different positions. A SPDT (Single Pole Double Throw) relay has one set of contacts that can be switched between two different positions.
What to look for when buying a DPDT relay?
- Voltage rating: Make sure the relay you are buying is rated for the voltage you need. 2. Current rating: Make sure the relay can handle the current you need it to switch.
- Coil resistance: Check that the coil resistance is compatible with your power supply. 4. Contact material: Check that the contact material is suitable for your application.
- Mounting type: Make sure the relay can be mounted in the way you need it to be.
- Environmental rating: Make sure the relay is rated for the environment it will be used in.
- Contact arrangement: Make sure the relay has the contact arrangement you need.
- Operating temperature: Check that the relay can operate in the temperature range you need it to.
- Life expectancy: Check that the relay has a long enough life expectancy for your application.
What is the price of DPDT relay?
The price of a DPDT relay can vary depending on the type, size, and features. Generally, you can expect to pay anywhere from $2 to $20 for a basic DPDT relay. More advanced relays with additional features may cost more. The price will also depend on where you buy the relay. Some suppliers may offer discounts or bulk pricing. The DPDT brand will also have an impact on the pricing. Some brands may be more expensive than others. Especially if they are well-known for manufacturing and supplying quality electronic products.
I hope you now know the essentials of DPDT relays and how they work. DPDT relays are a great way to control two separate circuits using only one switch.
They are easy to install, cost-effective, and can be used in a variety of applications.
So if you’re looking for a reliable and versatile.
And in case you want to buy DPDT in China, consider contacting ICRFQ. We are a reputable supplier of DPDT relays and other electrical components. We offer competitive prices and fast delivery times.
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