Motor Starter
What is a Motor Starter?
A motor starter is an essential electrical device used to start, regulate, and protect electric motors. When motors are started, they draw high currents, which can cause damage to the motor and the electrical system. A motor starter mitigates this by gradually increasing the motor’s power, thereby minimizing the initial current surge and ensuring a controlled and smooth start. It consists of contactors that enable or disable the electrical connection to the motor, overload protection to protect against excessive currents, and a control circuit to manage the motor’s operation. Motor starters are indispensable in a variety of industries, from manufacturing to transportation, as they guarantee motor performance that is both dependable and safe.
Why do we need to connect a Starter with Electrical Motors?
There are numerous reasons why motor starters are essential. Initially, they limit the starting current to prevent damage to the motor and electrical infrastructure. This protection extends the motor’s life and lowers its maintenance expenses. Second, starters facilitate a smooth starting process, reducing mechanical stress on connected machinery and preventing sudden jolts. In addition, starters provide overload protection by automatically disconnecting the motor in the event of excessive currents, thereby preventing potential motor failures. In applications requiring bidirectional motor motion, certain motor starters feature reversing functionality. Motor starters ultimately improve motor operation efficiency, safety, and control.
How an industrial motor starter operates and its working principle?
A combination of electromechanical and electronic components enables the operation of an industrial motor starter. The control circuit energizes the main contactor’s coil when the start button is pressed. This connects the motor to the power source by closing the contactor’s main contacts. Overload relays also monitor the motor current. If the current exceeds the permissible limits, the overload relays will trip, disabling the motor. The stop button releases the energy of the control circuit, de-energizing the main contactor and halting the motor. Motor starters utilize auxiliary interlocks to ensure proper sequencing and prevent unsafe operating conditions.
Types of Motor Starters:
• High torque
• Low torque
• Slow starting speed
• High starting speed
• Combinations of above or time variants based on the connected loads
High Torque Motors:
Advantages |
Disadvantages |
|
|
|
|
|
Low Torque Motors:
Advantages |
Disadvantages |
|
|
|
|
|
Slow Starting Speed:
Advantages |
Disadvantages |
|
|
|
|
|
High Starting Speed:
Advantages |
Disadvantages |
|
|
|
|
|
|
Motor ElementsA typical motor starter would consist of an incoming power connection (Single or three phases) connected to a protection system such as a fuse block or a circuit breaker with or without a locking option, contactor switchgear with an overload relay integrated or separately connected and the power delivery cable terminated directly to the field motor or to intermediate terminal blocks. The probable variation to this would include a soft starter or a variable frequency drive after the contactor. The control elements would include selector switches such as Auto/ Manual, Local / Remote, and push buttons such as Motor Start/ Stop and Pilot indicators for the status. The actuation of the motor could happen from a controller such as PLC in automatic control schemes. Depending on where the control system (maybe PLC or Motor control relay) is located, the control and monitoring wiring signals such as motor winding temperature/ vibration/ overload/ motor operation status/ motor run forward reverse signals/driven equipment signals may land inside the motor starter panel. Note: Standard market available starters are Direct-On-Line Starter, Star-Delta Starter, Reversing starter, Soft Starter, VFD starter |
Options Available
4X Stainless Steel or Fibre Glass Enclosure, Floor Mount Kit, Inner Door for controls, NEMA Style Contactors, Electronic Overloads, Multiple motor control, Duplex pump Control, Automatic Transfer Control, Multi winding/speed motor control, Enclosure Heater, Single Phase Application, Custom Controls, Class1 Div1 or 2 starters in the X-Proof Enclosures and Purge Panels.