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Which of motor is used for compressor?
DC series
Shaded pole
Capacitor start capacitor run
Reluctance
Capacitor start capacitor run
Compressors require a high starting torque to overcome the initial heavy load and gas pressure during startup. A Capacitor-Start Capacitor-Run (CSCR) single-phase induction motor provides high starting torque due to the starting capacitor, along with high running torque and high efficiency during operation due to the running capacitor.
Compressors require a high starting torque to overcome the initial heavy load and gas pressure during startup. A Capacitor-Start Capacitor-Run (CSCR) single-phase induction motor provides high starting torque due to the starting capacitor, along with high running torque and high efficiency during operation due to the running capacitor.
TsтАЛтИЭImтАЛIaтАЛsin╬╕ тАФ Starting torque of a single-phase induction motor
╧ХтЙИ90┬░ тАФ Phase angle between main and auxiliary winding currents using capacitors
The starting capacitor creates a large phase angle difference (close to 90┬░) between the main winding and auxiliary winding currents, generating a strong rotating magnetic field for high starting torque. Once the motor reaches around 75% to 80% of synchronous speed, a centrifugal switch disconnects the start capacitor while leaving the run capacitor in series with the auxiliary winding to ensure optimal running torque and power factor.
Capacitor-start capacitor-run motors deliver a high starting torque up to 300% of full-load torque.
The start capacitor is an electrolytic type short-rated capacitor, while the run capacitor is an oil-filled continuous-rated type.
The presence of a running capacitor improves power factor, operational efficiency, and reduces noise.
High starting torque suitable for heavy-duty startup loads
Better running efficiency and power factor during steady state
Quieter performance with reduced vibration
Higher initial cost due to two capacitors and a centrifugal switch
Slightly more complex maintenance compared to basic split-phase motors
Refrigeration and air-conditioning compressors
High-pressure water pumps
Conveyors and heavy machine tools
Option A (DC Series Motor): Used in applications requiring extremely high starting torque such as electric traction and cranes, but not typical for standard household/industrial single-phase gas compressors.
Option B (Shaded Pole Motor): Has very low starting torque and low efficiency; used in light loads like small desk fans.
Option D (Reluctance Motor): A constant-speed synchronous motor used in applications like timers and recording instruments.
C is correct тАФ Capacitor start capacitor run motors provide high starting torque required to overcome initial compressor back-pressure as well as high running efficiency.
Always pair compressor load requirements with high starting torque motors (Capacitor Start Capacitor Run or CSIR), whereas low-starting torque loads like small fans use Shaded Pole or Permanent Split Capacitor motors.