Types Of Single Phase Motors

Shaded pole

Split phase

CSIR Capacitor Start Induction Run

CSCR Capacitor Start Capacitor Run

PSC Permanent Split Capacitor

RSIR Resistive Start induction Run

Shaded Pole Motors

-Cheap

-Not Efficient

-Very low starting torque

Split Phase Motors

• 
  Motor Starting:
  -Power applied
  
  -Current Draw LRA
  
  -Current relay is energized
  
  -Current relay contacts close and complete path to start winding
  
  -Motor starts
  
  -Current draw decreases to RLA level
  
  -Current relay coil de-energized
  
  -Contacts open
  
  
  NOTE:
  -Low starting torque
  
  -Starting current is high
  
  -Efficiency is high
  
  -Limited to fractional size HP such as capillary tube systems
  
  

CSIR Capacitor Start Induction Run

• 
  Motor Starting:
  -Power applied to windings
  
  -Current Draw (LRA)
  
  -Rotor begins to turn
  
  -Back EMF is created in the start winding exceeding applied voltage
  (Transformer Effect)
  
  -At 75% rated speed back EMF opens contacts on potential relay
  
  -Current draw decreases to RLA level
  
  
  NOTE:
  -Good for applications of unequal pressure
  
  -Usually limited to fractional HP
  
  

CSCR Capacitor Start Capacitor Run

• 
  Note:
  -Current relays are not recommended for CSCR motors because of the danger of the running capacitor discharging to the start capacitor through the current relay when it closes. Also the high voltage from the run capacitor can cause the current relay to arc possibly welding contacts together and lead to compressor failure
  
  CSCR
  -High efficiency
  
  -High Power factor
  
  -High starting torque
  
  -Single phase Motors
  
  -Fractional HP to 5 HP
  
  

PSC Permanent Split Capacitor

-Multi phase motors

-These Models have two parallel windings with nine leads that must be wired correctly for voltage + power supply

-If not wired correctly (Out of phase) motor overheating + possible failure can occur

RSIR Resistive Start Induction Run