3 phase Motor Changeover:

This diagram shows how to make 3 phase motor changeover. In this circuit diagram, we use a TP MCB ( Tripple Pole Miniature Circuit Breaker ), an SP MCB ( Single Pole Miniature Circuit Breaker ), a reverse switch, two magnetic contactors, and a three-phase motor. This circuit diagram is very easy to connect if you want to know more about this circuit, please check our youtube video below the link.


Diagram of 3 phase Motor Changeover:

3 phase Motor Changeover

Components needed For this Project:

You can get the components from any of the sites below:

  1. TP MCB 20A [See Buy Click Amazon]
  2. SP MCB 10A [See Buy Click Amazon]
  3. Selector Switch (220V AC) [See Buy Click Amazon]
  4. Magnetic Contactor 40A [See Buy Click Amazon]
  5. 3 Phase Motor (5 HP) [See Buy Click Amazon]

*Please note: These are affiliate links. I may make a commission if you buy the components through these links. I would appreciate your support in this way!

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Components used to make the 3 phase Motor Changeover:

01. TP MCB:

The full meaning of MCB is Miniature Circuit Breaker for TP MCB. MCB is an electromagnetic switch or device. If for any reason a short circuit occurs in the supply line or load line (line to line or line to neutral) or in case of overload MCB. the MCB automatically trips and disconnects the main line circuit or household power supply Connection. TP MCB In 3 Pole MCB, Switching & Protection is affected in only 3-Phases and the Neutral is not part of the MCB. 3 pole MCB signifies the Connection of Three Wires for a 3-Phase system Red-Yellow-Blue Phase. 3-Phase Supply Only Without Neutral.

02. SP MCB:

In single-pole MCB, Switching and protection are Affected in only one Phase. Single phase supply to break the phase only. A single Pole breaker is Typically used with 120-volt Circuits, and a 6-20 amps Miniature Circuit Breaker. They are constructed with one Line Wire and one Neutral wire. A Single Pole switch is the most basic General-Purpose switch that you use to Control a light or another device from one location. These Switches have 2 Brass-Colored screw Terminals Connected to the hot Power source wires. Pole refers to the number of Circuits Controlled by the Switch SP Switches Control only one Switch Electrical Circuit.

03. Selector Switch:

A Mechanical Switch That can be rotated Left, right, or center to open or close the Electrical contacts is known as a Selector switch. The Main Function of This Selector Switch is to Control Devices and also to Switch Between a Minimum of 2 or Above Electrical Circuits. The Perfect Used for Selector Switch is When Used for Controlling the Output of a Device. We know that a Selector switch is Used to control the electrical current flow in a Circuit it can also be used to both Initiate and inhibit the Current Flow.

04. Magnetic Contactor:

A magnetic contactor is an electromagnetic switching device. It is generally used for controlling 3-phase Motors. The operation of a magnetic contactor is similar to that of a Relay. but a relay is used for low-power or low-voltage connections, and a magnetic contactor is used for high-power or high-voltage connections. As soon as the supply is applied to the magnetic contactor coil. its normally open contacts are closed and normally closed contacts are opened and the associated devices are also operated. This is how a magnetic contactor works.

05. 3-Phase Motor:

A 3-phase electric motor uses a 3-phase Power Supply to Convert Electric Energy into Mechanical Energy. It contains four Wires (Three hot Wires and one Neutral Wire) and Uses 3 Alternating Currents of the Same Frequency. Since it Generates a Rotating Magnetic Field, it does not need a Capacitor for the Startup. Some 3-phase Motors are Reversible, Which Means they can serve as Generators by Turning Mechanical Energy into Electrical Energy.

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Frequently asked questions

Why do swapping phases change motor direction?

The change in phase sequence changes the direction of current flowing through the windings of the motor which will eventually change the direction of the motor.

What is the most common cause of motor failure?

The most common cause of motor failure, or arguably the most difficult to overcome, is low resistance. Low resistance is caused by the degradation of the insulation of the windings due to conditions such as overheating, corrosion, and physical damage.

What causes a 3-phase motor to turn?

The rotor windings in an induction of the motor are either closed through an external resistance or directly shorted. Therefore, the e.m.f induced in the rotor of the causes current to flow in a direction opposite to that of the revolving magnetic field in the stator and leads to a twisting motion and torque in the rotor.

What causes a motor to trip?

Circuit diagram breakers and fuses trip for numerous reasons, Undervoltage, incorrectly designed circuit diagram breaker or fuses, too low a setting for the motor-protective circuit breaker, asymmetric 3-phase current, a short circuit on the motor, incorrect wiring or faulty electrical connections, worn and blocked pump, defective.

Why do we convert 3-phase to 2-phase?

Phase conversion from three to two-phase is needed in special cases, such as in supplying 2-phase electric arc furnaces. Scott connection of two-phase transformers is employed for the conversion of a three-phase system to a two-phase system or vice-versa.

Read more Single Phase Wiring