Single Phase Motor

What is a Single Phase Motor?

With non-complex structure and extended life, single-phase motors are the perfect example of “simple yet effective.” Single-phase motors are defined as electric motors that operate on single-phase power supply. Single-phase electric motors are suitable for domestic and low-volume industrial purposes due to their robust construction and low maintenance rate.

Single phase motors have two main parts: the stator and the rotor. The stator is the stationary part of the motor that houses the windings. The rotor is the rotating part of the motor that contains the magnets.

When single phase power is applied to the stator windings, a magnetic field is created. This magnetic field interacts with the magnets in the rotor, causing the rotor to turn. The speed at which the rotor turns is determined by the frequency of the single phase power.

Single phase motors are not as efficient as three-phase motors, but they are typically less expensive. They also have the advantage of being able to start and stop more quickly than three phase motors.

Different Types of Single Phase Motor

WLY is a modern enterprise specializing in producing all kinds of motors. Among them, single-phase motors for sale include YC/YCL and YL series single-phase motors, JY single-phase asynchronous motors and MY/ML aluminum shell single-phase asynchronous motors. We have rich experience and a strong ability to develop new products, have the ability to design the products based on your original samples.

How Does a Single Phase Motor Work?

We know that for the working of any electrical motor whether its AC or DC motor, we require two fluxes as the interaction of these two fluxes produced the required torque.

When we apply a single phase AC supply to the stator winding of single phase induction motor, the alternating current starts flowing through the stator or main winding. This alternating current produces an alternating flux called main flux. This main flux also links with the rotor conductors and hence cut the rotor conductors.

According to the Faraday's law of electromagnetic induction, emf gets induced in the rotor. As the rotor circuit is closed one so, the current starts flowing in the rotor. This current is called the rotor current. This rotor current produces its flux called rotor flux. Since this flux is produced due to the induction principle so, the motor working on this principle got its name as an induction motor. Now there are two fluxes one is main flux, and another is called rotor flux. These two fluxes produce the desired torque which is required by the motor to rotate.

Single Phase Motor Wiring Procedure

1. First, identify the starting winding and running winding terminals by measuring the resistance.

2. Connect any one terminal of each winding together, and it is to be connected to the neutral terminal of the power supply.

3. Connect the rest terminal of the running winding directly to the phase terminal of the power supply.

4. Connect the rest terminal of the starting winding to the phase terminal of the power supply through a series-connected capacitor.

Caution:

(1) There should not be any loose connection in the circuit.
(2) The running winding must be connected directly across the power supply, don't connect starting winding by mistake.
(3) Connect the capacitor with an appropriate rating, the rating should not be very less or very high.
(4) Connect the operating switch with phase only.
(5) Always, use a circuit breaker or any protective device, if your motor is heavy and costly.

220V Single Phase Motor Wiring Diagram

Single Phase Motor Wiring Diagram

How to Change Direction of a Single Phase Motor?

To change the direction of the motor rotation, just interchange the terminals of any one winding either starting winding or running winding. If the terminals of both windings are changed, the motor will rotate in the same direction. Do not disturb or change other connections while interchanging the winding terminals.

How to Test a Single Phase Motor with a Multimeter?

  • If you want to test your single-phase motor with a multimeter, you will need to follow these steps:
  • Firstly, disconnect the power supply to the motor.
  • Secondly, using your multimeter, set it to the Ohms function and measure the resistance between the two leads of the motor.
  • Thirdly, if the resistance is within the range specified in the manual, then the motor is fine. However, if the resistance is outside of this range, then there may be a problem with the motor.
  • Fourthly, once you have checked the resistance, you can then connect the power supply back to the motor and turn it on. If the motor does not start, then there may be a problem with the motor.
  • Finally, if the motor does start, but is running very slowly or making strange noises, then there may be a problem with the motor. In this case, you should contact a qualified engineer to diagnose and repair the problem.

Single Phase Motor Troubleshooting

During the operation of single-phase ac motors, it experiences various faults when starting or stopping or while running. The faults in single-phase motors are due to many reasons like overcurrents or undercurrents, over or under voltages, starter failure, motor overheating, over-loading, etc. Hence, it is essential to protect the motor from faults. Let us see the various faults and rectification or remedies for faults in single-phase ac motors.

Main Faults in Single-Phase Induction Motors :

1. Motor fails to start:

Causes Remedies
Supply may be cut off. Check the main supply with a test lamp at the motor's terminals and the starter terminals. Or in the main switch of the motor.
Overload or low starting torque. Rotate the rotor by hand and if it is free to move, then reduce the load.
Stator winding may be open-circuited or reversed coil connections. Check the windings and polarity of coils with the test lamp and if any end is found broken. Jcorrect them by making the connections of ends of each coil polarity. Join it or solder it, and if the polarity is wrong.
Open circuit in relay circuit or centrifugal switch. Check with a test lamp in the supply series and correct them.
The capacitor may be defective in a capacitor-type motor. Check the capacitor with a series test lamp and replace it.
The rotor shaft may be jammed in the bearings or brushes. Rotate the rotor shaft to see its free motion, check the bearings, and play.
The belt may be too tight. Check and set it in the correct order.

2. Fuses blown off as soon as the motor is started :

Causes Remedies
Protective gear may be defective. Check and set it in the correct order.
Motor may be overloaded. Check and reduce the load.
Starter winding may be short-circuited or earthed. Check the winding with a series test lamp or megger and correct it.
Connections of stator windings may be wrong. Check the connections physically and also with a series test lamp and correct them.

3. Motor starts and then stops :

Causes Remedies
Supply voltage may be too low. Check the supply voltage with a voltmeter and switch off the motor till the voltage increases.
Motor may be overloaded. Check the load physically and reduce it.
Connections of stator windings may be wrong. Check with a series test lamp and correct them.

4. Bearings over-heated :

Causes Remedies
Bearings may be squeezed. Check and grease them.
The belt may be too tight. Check and lose the belt.
The motor may be overloaded. Check and reduce the load.
The bent shaft of the rotor. Check and straighten it.
The rotor may be rubbing the stator cores. Check and set the rotor shaft position.

5. Motor's frame may be over-heated :

Causes Remedies
Misalignment of the drive. Check and correct it.
Adjustment of the may not be proper. Set it correctly.
Ventilation may not be proper. Maintain the proper ventilation.
Drive troubles. Check and correct.
Supply voltage may be too high. Check and switch off the motor till the voltage is reduced.
Motor may be over-loaded. Check the load on the motor physically and reduce it.
Short-circuit of stator winding or centrifugal switch may be short-circuited. Check the winding and check with a series test lamp or megger and correct it or get the motor re-wound.

6. Motor giving noise :

Causes Remedies
Motor loosely fitted on the foundation. Check and tighten the nuts.
Any part of the motor may be loosely fitted. Check and tighten it.
The rotor may be rubbing the stator core. Check and set the rotor shaft properly.
The bearing may be squeezed. Check and grease the bearings.

7. Speed of the motor is reduced suddenly :

Causes Remedies
Supply voltage may be reduced. Check with the voltmeter and stop the motor till the voltage is increased.
Open circuit in the stator winding. Check with the voltmeter and stop the motor till the voltage is increased.
The motor may be electrically or mechanically loaded suddenly. Check and reduce the load.

8. Speed of motor is increased suddenly :

Causes Remedies
Supply voltage is increased suddenly. Check the voltage with a voltmeter and stop the motor till the voltage falls to normal.
Load on the motor is reduced too much. Check and increase the load on the motor up to normal.

Single Phase Motor Uses

One of the best advantages of a single-phase motor is that it can be used in a wide range of applications. There are many different types of single-phase motors, each with its own specific set of advantages. However, the majority of single-phase motors are designed for use in domestic or light industrial applications.

1. Domestic appliances:
Single-phase motors are used in a wide range of domestic appliances, such as fans, washing machines, air conditioners, and refrigerators. They are also used in some types of pumps and compressors. Single-phase motors are typically smaller and more efficient than three-phase motors, making them ideal for use in domestic appliances.

2. Industrial machinery:
Single-phase motors are used in a wide range of industrial machineries, such as pumps, compressors, fans, and conveyors. They are also used in some types of machine tools and printing presses. Single-phase motors are typically more efficient and require less maintenance making them an attractive option for a variety of industrial applications.

3. Transportation and vehicles:
Single-phase motors are used in several transportation applications, such as electric bicycles and scooters. They are also used in some types of trains and buses.

4. Drilling machine:
A drilling machine is a power tool used for making holes in various materials, including wood, metal, plastic, and concrete. The single-phase electric motor is the most common type of motor used in drilling machines. This type of motor is reliable and easy to maintain, making it a good choice for heavy-duty applications.

Drilling machines come in a variety of sizes and styles, and each is designed for a specific purpose. For example, some drilling machines are designed specifically for woodworking, while others are better suited for metalworking.

5. Manufacturing toys:
Another application of single-phase motors is that it is installed in toys. This type of motor is reliable and easy to maintain, making it a good choice for children's toys. Single-phase motors are also inexpensive, which makes them a popular choice for mass-produced toys.

6. General use:
Single-phase motors are also used in a wide range of other applications, such as office equipment, medical equipment, and industrial. They are also used in some types of vending machines and ATMs. Single-phase motors are a better choice for many applications because they are more productive, useful, and require less maintenance.

Single Phase Motor Manufacturers

WLY TRANSMISSION CO.LTD. is a professional supplier of motor-integrated solutions. We have a professional technical team to provide technical services for custom motors. Our main products include AC motor both low voltage and high voltage, squirrel cage motor, , , vibration motor, slip-ring motor, DC motors, special application motors etc.

Through modern management, R&D of core technology and investment in advanced manufacturing equipment, WLY has achieved rapid development. Its products have been exported to more than 40 countries and regions, such as Germany, the United States, Italy, Britain and the Netherlands. Its products are deeply recognized by the majority of users. WLY is committed to providing reliable high-quality motor solutions for customers all over the world and achieving the success of more customers with good quality. Sincerely look forward to your cooperation!

Three-phase Motor Production Process
Three-phase Motor Production Process
Three-phase Motor Production Process

How To Speed Control for Single Phase Motor?

Using a variable motor speed controller is the most reliable way to control the speed of a single-phase motor. In this case, there is a problem related to torque. The motor's highest shaft torque is sometimes reduced at more than the rated rpm. Then, an additional cooling mechanism is required.

Besides, you can change the frequency, the number of poles, the winding current, etc., to achieve a controlled speed. But you must ensure that your single-phase motor can handle these changes. Otherwise, these changes can cause severe damage.

How to Test a Single Phase Motor?

It is not very complicated to test a 1 HP single-phase motor. You need to conduct regular inspections to verify the motor's performance. So, you need to have a deep understanding of the testing procedure of a 1 phase induction motor.

Single-phase motors usually face defective issues in the winding, resistance, insulation, full load current, etc. . That's why you should test these issues to ensure the smooth operation of a 1 hp single phase motor.

Full Load Amp Test

You need to conduct this test while the motor is running in full swing. You can use a multimeter to check the full load current rating.

Functional Test

This test helps get an idea about the real-time performance of this motor. In this case, you have to run the motor and check the rotor movement properly. Sometimes, the bearings get defective. Then, you should replace them as soon as possible.

Insulation Test

It is required to maintain a high resistance between the winding and the ground. This resistance should be more than 1 Mohm. It can be tested through an ohmmeter that has a high voltage rating.

Motor Winding Test

Use a resistance tester to verify the resistance between different terminals. You need to keep the start-run and common-run winding resistances maximum and minimum, respectively.

Besides, you need to test the performance of a single phase motor against high temperature and vibration. For that purpose, vibration tests and thermal tests are effective. It will be beneficial for you to contact a reliable manufacturer that has a well-equipped testing facility.