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AC Machines 6077 SA NUE 046. 1 Phase Induction Motors Identify the basic components of a 1Ø induction motor List the types of rotors used Test motor windings.

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Presentation on theme: "AC Machines 6077 SA NUE 046. 1 Phase Induction Motors Identify the basic components of a 1Ø induction motor List the types of rotors used Test motor windings."— Presentation transcript:

1 AC Machines 6077 SA NUE 046

2 1 Phase Induction Motors Identify the basic components of a 1Ø induction motor List the types of rotors used Test motor windings for suitability to connect to the supply Connect in both Clockwise and counter clockwise rotation List the steps for dismantling it At the end of this section you will be able to:

3 Types Squirrel Cage Split phase Capacitor start Capacitor start Capacitor run Permanent split phase capacitor run Shaded Pole Wound Rotor Series universal Repulsion

4 Construction

5 1.Low resistance 2.High X L 3.Set deeper in laminations to increase X L Run or Main Windings Start or Auxiliary Windings 1.High resistance (thinner wire) 2.Low X L (fewer turns) 3.Set shallower in laminations to limit X L

6 Electrical Characteristics Run Winding IRIR ISIS Start Winding Large phase Angle due to high Inductance Phase Angle less, as Inductance is less than run winding I Ref

7 Split Phase Motor Construction High resistance Low X L Low resistance High X L Switch opens 70 – 80% full load speed

8 Split Phase Motor Construction Low resistance High resistance

9 Split Phase Motor Construction Capacitor Start Motor

10 Electrical Characteristics IRIR ISIS I Ref Split Phase Capacitor Start Torque = K I R I S sinα α = Angle between I R and I S K = constant

11 Construction

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13 Shaded Pole

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18 Reluctance Motor Low efficiency Low torque Constant Speed Fractional sizes 1Φ Synchronous Machine

19 Reluctance Motor Same as: Split phase or Capacitor Start Motor Stator

20 Reluctance Motor Same as: Squirrel cage motor Rotor Uneven slots cut into laminations to form Salient poles BUT, with Uneven slots assist in starting Rotor Slots generally Stator Slots

21 Reluctance Motor Starting Motor becomes Synchronous As per induction motor with squirrel cage providing torque Centrifugal switch operating as per normal(75%) As motor is lightly loaded slip speed is small Rotor salient poles become magnetised and lock with RMF

22 Reluctance Motor If rotor poles are a multiple of the stator poles Motor will operate at sub-multiples of synchronous speed

23 Hysteresis Motor Rotor Outer section made up of hardened steel

24 Hysteresis Motor Rotor Outer section made up of hardened steel This outer section supported on the shaft by a NON-MAGNETIC Arbour

25 Hysteresis Motor Rotor has a very high Hysteresis loss The rotor tends to become magnetised A synchronous motor is born PROBLEM Synchronous motors have ZERO START TOURQUE! A Shaded pole stator is used

26 Universal Motor Not the same as a series DC Motor Fields are laminated for AC current

27 Universal Motor

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