A guide to the four fundamental elements of a motor starter

  • If you are working or know someone who is working at a factory or a process plant, then you know these are high-risk workplaces. You face the real danger of catastrophic events like explosions and fires. One thing that holds significant importance to plant safety is the safely controlling the high levels of electrical current flow that goes through multiple AC motors. 

    When you are installing any machinery with the help of electric motors, different types of fault might occur. Some of them might be circuit breakers, over voltage due to over power supply that can cause electrical sockets getting fused and overloading of the motor leading to power surge. The consequence of such faults can range from temporary shutdown to ruination of the motor and its starter components.

    When it comes down to motor startersthese protection elements are a combination of a switch dis-connector and the control device. To make sure that they perform their functions accurately, they should be well connected.

    To know how to solve this issue, below lies a quick guide of the four basic functions a motor starter performs.

    First step is to disconnect and break

    No matter what kind of motor starter it might be, it should be able to disconnect from the mains and isolate itself to prevent from restarting. The ability to switch off the power and isolate allows maintenance and repair work on the motor, driven equipment or its starter components to be carried out safely. 

    Then comes short-circuit protection

    The main obstacle that comes with turning off electricity is that it likes to flow. It will keep flowing and flow through the air- you can see it at your home when you see a little flash as you turn the light off. When in a domestic environment, the normal load current is just a few amps but under a short circuit fault, it can go as high as a few thousand amps. The Miniature circuit breaker in your distribution board are capable of clearing this fault current.

    When talking about the industrial environment, everything just escalates. The normal current in an industry can reach up to 1000 amps and the prospective fault current with a short circuit can reach up to or exceed 100,000 amps.

    How to tackle overload protection

    If you are wondering how overloads are caused then it due to the motor drawing more power than it is designed to use, invariably so as it being asked to perform more than it should. For instance, a conveyor belt that is moving heavier items than usual or a pump with a blockage.

    Due to overload protection it detects the excess current from the overload and then open up the circuit in order to prevent the motor from overheating and eventually draining it. In order to protect your machinery from overloading, one can use surge protection device

    Last but not the least-Control

    Controlling is the closing and opening of an electrical circuit which is under load and more often than not is carried out by contactors which was first invented by Telemecanique (part of Schneider Electric) in 1924.

    In the contractor there are main poles that do the switching. In order to open and close the poles it can be done by energising an electromagnet called a coil. In this, the coil is typically manufactured for either ac or dc voltage and it has a nominal control voltage. 

    Moreover, in order to protect your machinery from any mishaps, you can install protection relays or electrical relays for the same.