Single Phase Motor Connection With Two Capacitor

6 min read Jun 26, 2024
Single Phase Motor Connection With Two Capacitor

Single Phase Motor Connection with Two Capacitors

Introduction

Single phase induction motors are widely used in various applications such as fans, pumps, and compressors. However, they require a starting mechanism to initiate rotation. One common method is to use a capacitor-start motor, which employs a capacitor and a centrifugal switch to provide a starting torque. In this article, we will discuss the connection of a single phase motor with two capacitors.

Working Principle

A single phase motor with two capacitors uses the principle of phase shift to create a rotating magnetic field. The motor has two windings: the main winding and the auxiliary winding. The main winding is connected to the supply voltage, while the auxiliary winding is connected to the supply voltage through two capacitors.

The two capacitors, C1 and C2, are connected in series with the auxiliary winding. The values of the capacitors are chosen such that the impedance of the auxiliary circuit is capacitive. This creates a phase shift between the current in the main winding and the current in the auxiliary winding.

During starting, the capacitor-start motor behaves like a two-phase motor, with the main winding and the auxiliary winding producing a rotating magnetic field. Once the motor reaches its operating speed, the centrifugal switch disconnects the auxiliary winding, and the motor runs as a single phase motor.

Connection Diagram

The connection diagram for a single phase motor with two capacitors is shown below:

         +-----------+
         |          |
         |  Main    |
         |  Winding  |
         |          |
         +-----------+
                  |
                  |
                  v
         +-----------+
         |          |
         |  C1      |
         |  (Series) |
         |          |
         +-----------+
                  |
                  |
                  v
         +-----------+
         |          |
         |  C2      |
         |  (Series) |
         |          |
         +-----------+
                  |
                  |
                  v
         +-----------+
         |          |
         | Auxiliary |
         |  Winding  |
         |          |
         +-----------+
                  |
                  |
                  v
         +-----------+
         |          |
         | Centrifugal|
         |  Switch    |
         |          |
         +-----------+

Connection Procedure

To connect a single phase motor with two capacitors, follow these steps:

  1. Connect the main winding: Connect the main winding to the supply voltage (L1 and L2).
  2. Connect the capacitors: Connect capacitor C1 in series with capacitor C2. Connect the series combination to the auxiliary winding.
  3. Connect the auxiliary winding: Connect the auxiliary winding to the centrifugal switch.
  4. Connect the centrifugal switch: Connect the centrifugal switch to the supply voltage (L1 and L2).

Advantages

The use of two capacitors in a single phase motor connection offers several advantages:

  • Improved starting torque: The two capacitors provide a higher starting torque, making it suitable for heavy-load applications.
  • Reduced current: The capacitors reduce the current drawn from the supply, making it more energy-efficient.
  • Increased efficiency: The motor operates at a higher efficiency due to the improved power factor.

Applications

Single phase motors with two capacitors are commonly used in:

  • Fans and blowers: They are used in fans and blowers due to their high starting torque and efficiency.
  • Pumps and compressors: They are used in pumps and compressors due to their high torque and efficiency.
  • Household appliances: They are used in household appliances such as refrigerators and air conditioners due to their compact size and efficiency.

Conclusion

In conclusion, single phase motors with two capacitors offer improved starting torque, reduced current, and increased efficiency. They are widely used in various applications and are an essential component in many industries. By following the connection procedure and understanding the working principle, you can effectively use single phase motors with two capacitors in your applications.