What is the difference between running capacitor and starting capacitor

 The main differences between a running capacitor and a starting capacitor lie in their purpose, design, and how they function in an electric motor, particularly in single-phase induction motors. Here's a breakdown of their differences:

**1. Purpose:**

 **Starting Capacitor:**

  - Provides an initial boost of torque to start the motor.

   Only used during the starting phase of the motor to help it reach the correct speed.

**Running Capacitor:**

   Improves the running efficiency and performance of the motor once it starts.

  - Remains connected to the motor circuit while the motor is running.

 **2. Design and Capacitance Value:**

**Starting Capacitor:**

   Has a higher capacitance value (measured in microfarads, µF) compared to a running capacitor.

  - Typically ranges from 70 µF to 500 µF or more, depending on the motor size.

  - Designed to handle a short burst of energy during startup.

 **Running Capacitor:**

   Has a lower capacitance value, usually ranging from 5 µF to 50 µF.

  - Designed for continuous operation and can handle lower currents over a prolonged period.

 **3. Physical Characteristics:**

 **Starting Capacitor:**

  Larger in size and usually enclosed in a plastic or aluminum housing.

  - Electrolytic type, making them capable of storing a large charge quickly.

**Running Capacitor:**

  Smaller in size and often enclosed in metal housings.

  - Non-electrolytic, usually of oil-filled or metallized film type, which allows for continuous duty.

 **4. Connection and Operation:**

 **Starting Capacitor:**

   Connected in series with the motor's start winding and switched out of the circuit (disconnected) once the motor reaches about 75% of its full speed, often by a centrifugal switch or relay.

  

**Running Capacitor:**

  - Connected in series with the motor’s auxiliary (start) winding but remains in the circuit during operation.

 **5. Failure Impact:**

**Starting Capacitor:**

   Failure can result in the motor failing to start or struggling to start with lower torque.

  

**Running Capacitor:**

  Failure can cause reduced running efficiency, increased current draw, overheating, or even motor stalling.

 **Summary:**

 **Starting capacitors** help the motor start by providing an initial torque boost but are disconnected after startup.

**Running capacitors** help the motor run efficiently by improving its power factor and reducing power consumption, staying connected throughout operation.