Things about Tesla Polyphase Induction Motors - AC Motors - Electronics

Given that the short-circuited rotor windings have little resistance, even a little slip causes a big present in the rotor and produces substantial torque. At full ranked load, slip varies from more than 5% for small or unique purpose motors to less than 1% for big motors. Look At This Piece can trigger load-sharing issues when in a different way sized motors are mechanically connected.

Requirement torque [modify] Speed-torque curves for four induction motor types: A) Single-phase, B) Polyphase cage, C) Polyphase cage deep bar, D) Polyphase double cage Common speed-torque curve for NEMA Design B Motor Transient service for an AC induction motor from a complete stop to its operating point under a differing load.

Suitable for the majority of low performance loads such as centrifugal pumps and fans, Style B motors are constrained by the following normal torque varieties: Breakdown torque (peak torque), 175300% of rated torque Locked-rotor torque (torque at 100% slip), 75275% of ranked torque Pull-up torque, 65190% of ranked torque. Over a motor's typical load range, the torque's slope is around direct or proportional to slip since the value of rotor resistance divided by slip, R r/ s \ displaystyle R _ r '/ s, controls torque in a direct manner.

As the load torque increases beyond breakdown torque the motor stalls. Starting [modify] There are three standard kinds of small induction motors: split-phase single-phase, shaded-pole single-phase, and polyphase. In two-pole single-phase motors, the torque goes to zero at 100% slip (absolutely no speed), so these require changes to the stator such as shaded-poles to offer starting torque.

3-Phase Induction Motors (KIIS) - Oriental Motor Europa GmbH for Dummies

The typical running windings within such a single-phase motor can cause the rotor to turn in either direction, so the beginning circuit figures out the operating direction. Magnetic flux in shaded pole motor. In certain smaller sized single-phase motors, starting is done by methods of a copper wire turn around part of a pole; such a pole is referred to as a shaded pole.

This imparts enough rotational field energy to start the motor. These motors are usually used in applications such as desk fans and record players, as the needed starting torque is low, and the low efficiency is bearable relative to the reduced expense of the motor and starting technique compared to other Air Conditioning motor designs.