People are often left with this question, “Is it a motor starter or a contactor?” when they see one or there exists confusion about which one to buy.
The reason for this confusion and interchangeability of the terms is that they serve similar purposes of controlling electric motors and they have identical mechanical parts.
If that is the case what makes the best electric motor starter different from a contractor?
Let us know each of them differently and then see the difference.
Contactor
Contactors are widely used devices in the field of power distribution. It is a special type of relay used for switching an electrical power circuit and controlling many devices like electric motors, lighting, heating, thermal evaporators, etc.
Being composed of an electromagnetic system, contact system, and arc extinguishing device a contactor can have a breaking current of several to thousands of amperes.
Motor Starter
A starter can be simply defined as a contactor with an overload relay. It is majorly an electrical device that controls the use of electrical power to equipment.
As the name suggests, motor starters are used to ‘start’ motors and to stop, accelerate, and protect motors by dropping out the coil voltage if the motor overloads. Overload relays are used to shut the motor when load surges to prevent overheating.
How are they different?
- A contactor is an electrically controlled switch, whereas, a motor starter is a contactor with an overload relay.
- When a contactor uses voltage to a contactor coil to close the contacts and supply or interrupt power to the circuit, a starter employs overload relays to protect the motor when overloading happens by shutting it down, thus, preventing overheating.
- A contactor is without any overload protection special features. On the other hand, with a starter, we have options for different overloads to be used.
- Different types of contractors are generally classified by their varying voltage capacities. In the case of starters, their current capacity and the horsepower of the motor are taken into consideration.
- While contractors are exclusively designed and built to operate with normally open contacts, starters can operate with both normally open and/or normally closed, depending on the desired need of the situation.
Now you are well aware of how contactors and motor starters are different from each other even though they serve rather a similar purpose.
Contact the best machine tool industries in India and seek their guidance to know which one will suit your purposes.
