Okay, first, let us talk about motor starters; these are devices that are used to provide electrical power to all the equipment that is being used. As the name suggests, the starters “start” motors, but they can also stop them, accelerate them, reverse them, and protect them.

Starters usually comprise of two building blocks- mainly contactors and then overload protection:

• Contactors are so useful as they control the electric current of the motor. Their prime function is to repeatedly establish and interrupt an electrical power circuit, no matter the cause.

• Now, with the help of overload protection, it helps protect motors from drawing too much current and overheating it.”

Now let us focus on - Contractor

• A contractor, single-handedly stands on its own as an electrical power distribution device or acts as a part of a starter.

• If you are wondering where one can use it, then you can find one in applications ranging from the light switch to highly complex automated equipment used in various industries.

• You will always find a contractor that is placed in electrical equipment that is regularly turned on and off (opening and closing the circuit), for instance, lights, heaters, and motors.

Now that we know what these two terms mean, the next thing we need to cover is how people often get confused between contactors and relays. For a better understanding, below are a few things you should always keep in mind. 

Contactors VS Relay

If you go by the books, then both of them have a similar meaning and perform the same task. Now the question arises how do you differentiate contactor relay.

1. Load Capacity

Relays more often than not are classified as loads of 10A or less, while one would pick a contactor over relay for loads dealing greater than 10A, and if its anything less than that, you should opt for a relay.

2. Open/Closed Contact Standards

Contactors were exclusively designed to operate with normally open (Form A) contacts. While on the other hand, relays often function often on both normally open and/or normally closed depending on the desired function. In the end, the conclusion is that with the help of a contactor, when it is de-energized, there is (usually) no connection. Although with a relay there very well could be.

3. Auxiliary Contacts

Now when you are talking about contactors, it can be NO or NC; however, it is present to perform some additional functions that are directly related to the control of the contactor. For instance, the contactor can easily transmit power to the motor, although the auxiliary contact is inside the control circuit of the motor starter, and more often than not, it is used to turn on a pilot light indicating the motor is functioning. 

Hoping that this article provided you with more clarity regarding the contactors and motor starters. If you are trying to get your hands on the same, then you can put your trust on #Schneider Electric. They have great engineers and work really hard towards their products.