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Air Conditioning

Air Conditioning. Types of Motors. MOTOR START WINDINGS. Are a smaller diameter wire Have higher resistance Stronger magnetic field to get motor turning Must be removed from circuit as quick as possible or protected from excess current if left in the circuit Known as the phase winding

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Air Conditioning

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  1. Air Conditioning Types of Motors

  2. MOTOR START WINDINGS • Are a smaller diameter wire • Have higher resistance • Stronger magnetic field to get motor turning • Must be removed from circuit as quick as possible or protected from excess current if left in the circuit • Known as the phase winding • The winding all capacitors connect to

  3. MOTOR RUN WINDINGS • Larger diameter wire • Less resistance than start windings • Not removed from the electrical circuit • Not protected from excess current • Known as the main winding

  4. TYPES OF MOTORS

  5. Shaded pole motor -single speed or multi-speed -low running and starting torque -run winding only

  6. Split Phase Motor • run and start windings • start winding must be protected • starting relay removes start winding from circuit • low starting and running torque

  7. CSIR (capacitor start induction run ) • Not a common motor for AC units • Has a centrifugal switch or start relay to remove start cap and start winding from circuit once motor reaches 75 % of its rated RPM’s • Open type fan motor will have cent. switch • Compressor will have relay

  8. PSC ( Permanent Split Capacitor ) • Split phase motor with a run capacitor only • The run capacitor is wired in series with the start winding • No start relay or centrifugal switch needed • Run capacitor reduces the current flow through the start winding • Having the start winding in the circuit gives the motor good running torque

  9. CSCR-(Capacitor Start/ Induction Run • Basically a PSC motor, with a start capacitor and relay to drop out start cap. • High starting torque • A hard start kit is often installed on a PSC motor if it has difficulty starting

  10. MOTOR BEARINGS • Bearing type is determined by load and acceptable noise levels • Sleeve bearings • Used on light loads and low noise levels • Lubricated with oil • Ball bearings • Noisier than sleeve bearings • Lubricated with grease

  11. SLEEVE BEARINGS OIL PORT MOTOR SHAFT

  12. MOTOR MOUNTING TYPES • Determine how a motor will be secured during operation • Rigid motor mount – bolted to frame of fan or pump • Resilient or rubber mounts – reduced motor noise • Cradle mounts – motor sits in a cradle • Rigid-base mount – base mounted to the motor • End mount – used on small motors • Belly band strap mount – strap wraps around motor

  13. MOTOR DRIVES Direct drive • Motor shaft connected directly to the load • load turns at the same speed as the motor Belt driven • Uses V-belts and pulleys • load can rotate at different speeds

  14. BLOWER BOTH THE DRIVE AND DRIVEN PULLEYS MUST BE PERFECTLY ALIGNED MOTOR

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