Working Principle of NC in Relay and Its Application in Heavy Equipment

Relays are the basic components in the electrical systems of heavy equipment such as excavators, loaders, and trucks. A relay's normally closed contact (NC contact) is the most commonly used circuit control component. Understanding how NC contacts work in relays is important for heavy equipment maintenance.

 

What Are Relays and NC Contacts?

A relay is an electronic switch that uses a small amount of current to control a large amount of current. At its core, it uses an electromagnetic coil to control a change in the switching state. There are two types of relay contacts: normally open (NO) and normally closed (NC). The focus of this article is to discuss how NC contact works in relay.

 

The Normally closed contact, abbreviated as NC, remains closed when no current passes through the coil. When the coil is energized, the Normally closed contact opens to cut off the circuit.

 

How Does NC Contact Work in Relay?

To understand how NC contact works in relay, we can simply divide it into two states to discuss:

 

The unenergized state of the coil

When the relay coil is not energized, the normally closed contact is closed by default. This means that current can pass through the contacts without any problem and a circuit connection can be made. In heavy equipment, this design ensures that circuits remain operational when heavy equipment is turned off or malfunctions, such as cooling fans, emergency alarm systems, etc.

 

Coil Energized State

When a relay coil is energized, the electromagnetic force pulls the normally closed contacts open, breaking the circuit. This condition is typically used to disconnect non-critical functions or to automatically shut down certain components in the event of equipment failure.

 

Understanding how NC contact works in relays is very important because it helps us to make a more rational selection and configuration when using relays.

 

Practical Applications of NC Contacts

Normally closed contacts in relays play an important role in applications such as excavators, bulldozers, and cranes.

 

1. Emergency Stop Function

Normally closed contacts are widely used in emergency stop buttons. When the operator presses the emergency stop button, the normally closed contact opens and immediately cuts off power to the heavy equipment. Understanding how NC contacts work in the relay can help heavy equipment maintenance personnel troubleshoot problems.

 

2. Equipment Overload Protection

Normally closed contacts are used for equipment overload protection in the motor control of heavy equipment. When the current of the heavy equipment exceeds the safe range, the normally closed contact cuts off the circuit and protects the motor from damage.

 

3. Safety Circuit Management

Safety is always the priority when operating heavy equipment. Normally closed contacts also have a role to play in safety circuits. If one of the safety sensors or components is not functioning properly, the relay cuts off the main power supply via the normally closed contact.

 

How to Choose an Aftermarket Relay?

Load Capacity

Find out the current and voltage requirements of heavy equipment that the relay can withstand.

 

Operating Environment

Consider the temperature, humidity, and dust of the environment in which the heavy equipment operates. Select a relay that is adapted to harsh operating conditions.

 

Contact Type

Understand how NC contacts work in relays and ensure that the normally closed contacts of the selected relay meet the specific needs of the heavy-duty equipment.

 

When purchasing aftermarket relays, choose products that are of excellent quality and durability. Consistent quality relays for sale at the MyMROmarts store.

 

An in-depth understanding of how nc contact works in relays can help equipment owners better manage their heavy equipment's electrical systems and avoid potential risks. At the same time, purchasing quality aftermarket relays is critical to the safe operation of heavy equipment.