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Shaded Pole Motor

    • 1328 posts
    October 14, 2021 4:31 PM HKT

    YOUR Shaded Pole motor is an AC single phase induction generator. The auxiliary winding, that is composed of a birdwatcher ring, is called a new shading coil. The current in this kind of coil delay the action of magnetic flux as part of the pole to be able to provide a rotating of our field. The direction of rotation is through the unshaded side to your shaded ring.
    The shaded-pole motor may be the original type of ALTERNATING CURRENT single-phase induction motor, dating back to at least since 1890. [1] A shaded-pole motor is really a small squirrel-cage motor in which the auxiliary winding is constructed from a copper ring or bar surrounding some of each pole. [2] When single action AC supply is given to the stator winding, thanks to shading provided to that poles, a rotating magnetic field is generated. This auxiliary single-turn winding is called a shading coil. Currents induced during this coil by the magnetic field develop a second electrical phase by way of delaying the phase connected with magnetic flux change for your pole (a shaded pole) enough to provide a 2-phase rotating magnetic field. The direction of rotation is on the unshaded side to your shaded (ring) side of the pole. [2] Since that phase angle between that shaded and unshaded areas is small, shaded-pole motors produce merely a small starting torque comparable to torque at 100 % speed. Shaded-pole motors belonging to the asymmetrical type shown will be only reversible by disassembly and flipping covering the stator, though some similar looking motors have small, switch-shortable auxiliary windings of thin wire as opposed to thick copper bars and may reverse electrically. Another method of electrical reversing involves three coils (two pairs associated with identical coils). [3]

    The common, asymmetrical form of these kind of motors (pictured) has only one winding, with no capacitor or even starting windings/starting switch, [4] doing them economical and dependable. Larger and more modern types may have multiple physical windings, though electrically only 1, and a capacitor can be utilized. Because their starting torque can be low, they are suitable to driving fans or other loads that happen to be easily started. They could possibly have multiple taps near one electrical end with the winding, which provides variable speed and power by offering of one tap at the moment, as in ceiling fans. Moreover, they are suitable for TRIAC-based variable-speed controls, which often are utilized with fans. They are made in power sizes as much as about 1⁄4 horsepower (190 W) expenditure. Above 1⁄3 horsepower (250 W), they aren't common, and for much larger motors, other designs offer you better characteristics. A main disadvantage is their very low efficiency of around TWENTY SIX %. [5] A major advantage is that the motor's stall current should be only slightly higher than that running current, so there is very low risk of severe over-heating or maybe tripping the circuit protection if the motor is stalled for some reason. Since the current from the secondary winding of a transformer is out of phase with the current in the primary winding.
    The current in the shading coil is out of phase with the current in the main field winding.
    Thus, the flux with the shading pole is from phase with the flux in the main pole.