A two-value capacitor-run motor starts with a ________ capacitor and runs with a ______ capacitor.

A two-value capacitor-run motor starts with a ________ capacitor and runs with a ______ capacitor.

Right Answer is:

High: Low


A two-value capacitor-run motor starts with a High capacitor and runs with a Low capacitor.

Capacitor start capacitor run motors

  • This type of motor is designed to operate with the start winding and it is a series capacitor permanently connected to the supply.
  • lt has two capacitors connected in parallel in the start winding circuit for starting purposes.
  • A start capacitor stays in the circuit long enough to rapidly bring the motor up to a predetermined speed, which is usually about 75% of the full speed, and is then taken out of the circuit, often by a centrifugal switch that releases at that speed.
  • In a capacitor start and run the motor the function of the running capacitor in series with the auxiliary winding is to Improve power factor.
  • Run capacitors are designed for continuous duty while the motor is powered, which is why electrolytic capacitors are avoided.
  • As a result, this motor has a higher starting torque as well as a higher efficiency. These motors are employed in sizes ranging from 375 W to 7.5 kW.  The power factor of these motors is upto 80% to 100%.



  • Inductive Loads consume Reactive Power and Capacitive Loads deliver Reactive Power.
  • The Power Factor Angle is inversely proportional to the Power Factor (reducing the angled gap between the Voltage vector and the Current Vector improved power factor).
  • So in a single-phase Induction Motor, a Capacitor Bank is connected, then the Reactive power demand by the Inductive load (Induction Motor) is supplied by the Capacitor Bank, not from the Source.
  • Therefore the system reactive power demand is reduced and the Power factor is improved.
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