Fractional Kilowatt Motors

AC Series Motor

AC Series Motor: A series motor can be run from either dc or ac (single-phase) supply provided that both stator and rotor cores are laminated to limit the iron-loss. Figure 10.43 is the cross-sectional view of a AC Series Motor connected to ac supply. As the armature current alternates, the field polarity alternates in phase …

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Hybrid Stepper Motor

Hybrid Stepper Motor: Hybrid Stepper Motor -This is in fact a PM stepper motor with constructional features of toothed and stacked rotor adopted from the variable-reluctance motor. The stator has only one set of winding-excited poles which interact with the two rotor stacks. The permanent magnet is placed axially along the rotor in form of …

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Permanent Magnet Stepper Motor

Permanent Magnet Stepper Motor: Figure 10.39 shows the phases (stacks) of a 2-phase, 4-pole permanent magnet stepper motor. The rotor is made of ferrite or rare-earth material which is permanently magnetized. The stator stack of phase b is staggered from that of phase a by an angle of 90° elect. When the phase a is …

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Stepper Motor

Stepper Motor: The stepper motor is a special type of synchronous motor which is designed to rotate through a specific angle (called a step) for each electrical pulse received by its control unit. Typical step sizes are 7.5°, 15° or larger. The stepper motor is used in digitally controlled position control systems in open loop …

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Two phase Servomotor

Two phase Servomotor: Two phase Servomotor – For a low-power (a few hundred watts) control application, a 2-phase (balanced) servomotor is ideally suited as it can be driven by means of a relatively rugged (drift-free) ac amplifier. The motor torque can be easily controlled by varying the magnitude of the ac voltage applied to the …

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Single phase Synchronous motors

Single phase Synchronous motors: Single phase Synchronous motors – The 3-phase reluctance motor has already been discussed as an unexcited salient-pole synchronous machine in Sec. 8.11. The expression for reluctance torque of a single-phase device was derived in Sec. 4.3 from basic principles of energy conversion. The reluctance motor, in general, results wherever the stator …

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Shaded Pole Motor

Shaded Pole Motor: Shaded Pole Motor – Figure 10.17 shows a typical shaded-pole motor with a squirrel-cage rotor. A small portion of each pole is covered with a short-circuited, single-turn copper coil called the shading coil. The sinusoidally-varying flux created by ac (single-phase) excitation of the main winding induces emf in the shading coil. As …

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Split phase Motor

Split phase Motor: Split phase Motor -When a motor is provided with two windings, even though these are excited from the same voltage (supply being single-phase), the currents in the two windings can be made out-of-phase by adjustment of the impedance of the auxiliary winding in relation to the main winding. As a result F̅m and …

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