How to Wire an AC Motor?
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How to Wire an AC Motor?

Views: 0     Author: Site Editor     Publish Time: 2022-04-22      Origin: Site

If there is a manufacturer's manual, the wiring of the Ac motor is not particularly difficult. However, if the manual is not found, the work will become more difficult. In all cases, if you are not sure how to connect the motor, please consult an expert, because incorrect motor wiring can cause electric shock or injury. If you can’t find a wiring diagram, it is wise to buy a new motor instead of risking some uncertain things.

This passage is going to talk about the followings of electric motor:

(1)   The history of electric motors

(2)   Steps to wire an electric motor

(3)   Design and operation theory of Ac motor

servo-motor-series-400-400 (1)

The history of electric motors

The term "induction" in induction motors (also called asynchronous motors) refers to electromagnetic induction, which is the working principle of induction motors. According to Wikipedia, there are several names related to the invention of AC induction motors. In 1824, the French physicist François Arago discovered the rotating magnetic field and coined the term Arago's rotation (or Arago's disc). In 1831, Michael Faraday explained this influence by introducing the theory of electromagnetic induction. In 1879, Walter Baily demonstrated the first primitive induction motor by manually opening and closing the switch. The first three-phase induction motor without AC commutator was independently invented by Galileo Ferraris in 1885 and Nikola Tesla in 1887. Both companies published papers explaining these techniques in 1888. Tesla applied for US patents in 1887 and obtained some of them in 1888. At that time, George Westinghouse, who was developing an AC power system, obtained Tesla's patent license in 1888 and purchased the US patent for the Ferrari induction motor concept to further develop the technology. General Electric (GE) began developing three-phase induction motors in 1891. By 1896, General Electric and Westinghouse had signed a cross-licensing agreement for the design of a bar winding rotor, which was later called a squirrel-cage rotor. The same concept is still used today.

Steps to wire an electric motor

Before wiring any Ac motor, be absolutely sure to remove all electricity from the motor circuit. Turn on the circuit breaker that will provide power. Mark the circuit breaker to ensure that power is not accidentally restored to the circuit.

Check the motor manufacturer's manual for advice on proper wiring for your application. If the motor does not have a manual, please look for the connection diagram somewhere on the motor. The schematic can be on the outside of the motor, or under the inspection board or cover of the motor.

For the connection diagrams of most modern motors, see References. Find the correct wiring for your specific motor. For example, if the motor is single-phase single-voltage and you want it to rotate counterclockwise, it will show that the input power is connected to L1 and L2.

Open the motor cover to access the motor terminals. Strip the end of the power cord and crimp the terminal. Connect the wires to the motor terminals. Use a wire cap to connect the wires together for proper rotation.

After the wiring is complete, replace the cover and energize the motor circuit. Make sure the motor is running in the correct direction.

Design and operation theory of Ac motor

The most basic Ac motor is also called permanent split capacitor motor. The rotating element, the rotor, is supported in the motor housing by two ball bearings, which has a long service life. The stator is located around the rotor with a thin air gap. The output shaft is connected to the rotor. The wire is connected to the stator winding. Press-fit the flange bracket into the motor housing to ensure quality.

When alternating current is supplied to the copper windings in the stator, a rotating magnetic field is generated around the rotor at the speed of AC oscillation. According to Fleming's left-hand law, the moving magnetic field induces current on the aluminum bars (conductors) in the steel rotor, thereby generating its own diamagnetic field (Lenz's law). Then, the magnetic field from the rotor interacts with the rotating magnetic field from the stator, and the rotor starts to rotate.

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