Relay latching is a technique used to hold the relay contacts in a specific state after the coil has been de-energized. This technique is commonly used in power systems, automation, and control circuits. A relay latching circuit consists of two coils: a set coil and a reset coil. The set coil is energized to set the relay contacts, and the reset coil is energized to release the relay contacts. In this article, we will discuss the 120 relay latching wiring diagram, which is widely used in industrial applications.
What is a 120 Relay?
A 120 relay is a type of electromechanical relay that operates on 120 volts AC power. It has two sets of contacts that can be used for switching high current loads. The contacts are usually rated for a current of 10 amps or more. The 120 relay is commonly used in industrial control circuits, HVAC systems, and lighting control systems.
Features of 120 Relay
The main features of the 120 relay are as follows:
- Operates on 120V AC power
- Two sets of contacts
- Contacts rated for high current loads
- Fits in standard relay sockets
- Easy to install and maintain
What is a Latching Relay?
A latching relay is a type of relay that remains in its last state when the power is removed. It uses two coils to set and reset its contacts. The set coil is energized to set the contacts, and the reset coil is energized to release the contacts. The latching relay is commonly used in power systems, automation, and control circuits.
Features of Latching Relay
The main features of the latching relay are as follows:
- Remains in its last state when power is removed
- Uses two coils to set and reset contacts
- Low power consumption
- High switching frequency
- Long life cycle
120 Relay Latching Wiring Diagram
The 120 relay latching wiring diagram consists of two 120 relays, two push-button switches, and a few other components. The wiring diagram is shown below:
| Component | Description |
|---|---|
| Set Relay | A 120 relay with a set coil and two sets of contacts |
| Reset Relay | A 120 relay with a reset coil and two sets of contacts |
| Push-button Switch 1 | A momentary switch to energize the set coil of the set relay |
| Push-button Switch 2 | A momentary switch to energize the reset coil of the reset relay |
| Power Supply | A 120V AC power supply |
| Load | A high current load to be switched by the relay contacts |
The wiring diagram is shown in Figure 1.
Wiring Instructions
The wiring instructions for the 120 relay latching wiring diagram are as follows:
- Connect the power supply to the set and reset relays.
- Connect the load to the set and reset relay contacts.
- Connect one terminal of Push-button switch 1 to the set relay coil, and the other terminal to the power supply.
- Connect one terminal of Push-button switch 2 to the reset relay coil, and the other terminal to the power supply.
- Connect the common terminal of both the relays to the power supply.
The wiring diagram is shown in Figure 1.
FAQs
What is the purpose of using a latching relay?
A latching relay is used to hold the relay contacts in a specific state after the coil has been de-energized. It eliminates the need for continuous power supply to maintain the relay contacts in a specific state. This makes it suitable for power systems, automation, and control circuits.
How does a latching relay work?
A latching relay works by using two coils to set and reset its contacts. The set coil is energized to set the contacts, and the reset coil is energized to release the contacts. Once the contacts are set or released, they remain in their last state even if the power is removed.
What is a 120 relay used for?
A 120 relay is used for switching high current loads in industrial control circuits, HVAC systems, and lighting control systems. It operates on 120V AC power and has two sets of contacts that can be used for switching high current loads.
What is the difference between a 120 relay and a latching relay?
A 120 relay is a type of electromechanical relay that operates on 120V AC power, while a latching relay is a type of relay that remains in its last state when the power is removed. A latching relay uses two coils to set and reset its contacts, while a 120 relay does not.
