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Learn the Fundamentals of the Motor Circuit


A motor circuit is part of a motor which delivers high voltage current to an electric motor. In order to understand motor circuits better, we need to understand what a motor is and its various types. An electric motor might be direct current (DC), single-phase alternating current (AC), or three-phase alternating current (AC). Incoming power lines need to have a device for turning off, locking out, and tagging out circuit power. They must also incorporate fuses or circuit breakers of the appropriate size to protect the system. A magnetic motor starter or a motor drive can control a motor.

That combines the functionality of low-voltage circuit breakers with thermal overload relays. This device can safeguard motor branch circuits against overload, phase loss, and short-circuiting on its own. It makes wiring and motor protection even more secure.

The Function of Motor Control Circuit

Disconnection, circuit on/off switching, short-circuit protection, device protection, motor control, and overload protection are all required functions of the motor circuit.

A motor circuit made up of low-voltage circuit breakers, magnetic contactors, and thermal overload relays is commonly used, and each device serves an autonomous purpose. In contrast, in a motor circuit consisting of a Motor circuit breaker and a Magnetic Contactor, the Magnetic Contactor provides only motor control, and the Motor circuit breaker provides all other functions.

The primary function of a motor control circuit is to manage the AC motors. A higher voltage is necessary to start the motor, whereas a voltage lower than the starting voltage is required to operate. Therefore, the basic function of a motor control circuit is to change the voltage of the motor from high to low.

Types of Motor Circuits

There are three major types of motor circuits; They are:

Direct On-line Starter: This is a type of motor circuit which is used in smaller motors which use electricity up to 10 kW. Fuse and circuit breakers are often utilized in overcurrent protection circuits. In case, the current in the line exceeds the rated motor current, fuses and circuit breakers are set to break the connection.

Auto Transformer Starter: This type of starter is an assembly of contractor, overload block, control power transformer as well as power fuses. The motor, which can be indefinitely linked in a delta or a star configuration, is started on a reduced voltage from a 3-phase tapped autotransformer and then switched to the running (full voltage) position after it has accelerated progressively. The star contactor will be energized first in this control system. The transformer contactor will be activated shortly after.

Star Delta Starter: The Star Delta methods employ lower supply voltage beginning. This applies to motors designed for delta connection under typical operating conditions. In this type of motor circuit, cage motors of medium and larger capacities are started at a lower supply voltage to reduce starting current.

Join Hands with a High-Quality Product Distributor

When looking to buy high-quality motor circuits, make sure you do thorough research on the market and its various competitors. Consumers should compare various prices as well as the quality in the market. The warranty period is another critical factor that can help you determine the best service provider for your needs. A good service provider will guide you every step of the way when buying and installing motor circuits and make the entire process as smooth as possible.