If you’re an electrical engineering student, you might have probably come across various terminology related to starters and their applications and pros and cons about each of them. The device that gets used to toggle the switches automatically or manually to start or stop electric motors. The motor starter (มอเตอร์ สตาร์ท เตอร์, which is the term in Thai) also helps in providing overload protection to the circuits of the motor. You can use them wherever you find the machine motors getting operated over a particular horsepower.
The fundamental functions that it performs are safely starting/stop the motor, or it can also reverse the momentum and protect the device from low voltage or over current too. And it is made of two essential components that work together to perform the functions that are the electrical contactor and overload protection circuit.
The industrial motors have a low armature resistance. And if you connect the device with the power supply, it will not be able to handle the current flow and will destroy the armature winding due to low resistance. A starter reduces the current as the armature will need a low current at the initial stage, and then it can run at a usual speed.
A starter acts as a toggle switch for the motor to turn it on/off either by manual intervention or automatically through smart programming. It safeguards the electrical motors by forming and separating the contacts. Here you get the two options to work with, i.e., manual or automatic. In the manual, you will need to toggle the switch for every operation, and the manual intervention is more. And there is a possibility that initially, it will let a high amount of current flow at the initial start itself, and this may destroy the device.
Direct Online Starter:
One of the most manageable motor starter, in which the motor is attached directly to the power supply, is the direct online starter. It gets mostly used across the machine that has less than a five horsepower rating. You can find pushbuttons over it to toggle the switch that can power on/off the device.
- It has a simple and cost-effective design.
- You can easily understand the operation of its working.
- The torque it provides is initially high due to the high start current flow.
- The high amount of current can destroy the motor.
- The high amount of current can cause a dip in the voltmeter.
- It cannot get used for heavy industrial motor usage.