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The digits following the letter codes indicate the difference in phase angle between the windings, with HV winding is taken as a reference. The number is in units of 30 degrees. For example, a transformer with a vector group of Dy1 has a delta-connected HV winding and a wye-connected LV winding. The phase angle of the LV winding lags the HV by ...
Induction motors are most commonly run on single-phase or three-phase power, but two-phase motors exist; in theory, induction motors can have any number of phases. Many single-phase motors having two windings can be viewed as two-phase motors, since a capacitor is used to generate a second power phase 90° from the single-phase supply and feeds ...
The shaded-pole motor is the original type of AC single-phase electric motor, dating back to at least as early as 1890. [1] A shaded-pole motor is a motor, in which the auxiliary winding is composed of a copper ring or bar surrounding a portion of each pole to produce a weakly rotating magnetic field . [ 2 ]
Alphanumeric designations are typically in the form H 1 for primaries, and for secondaries, X 1, (and Y 1, Z 1, if more windings present). Unlike single-phase transformers, three-phase transformers may have a phase shift due to different winding configurations (for example, a wye connected primary and a delta connected secondary), resulting in ...
The rotating magnetic field is the key principle in the operation of induction machines.The induction motor consists of a stator and rotor.In the stator a group of fixed windings are so arranged that a two phase current, for example, produces a magnetic field which rotates at an angular velocity determined by the frequency of the alternating current.
Single-phase motors may have taps to allow their use on either 208-volt or 240-volt supply. A single-phase load may be powered directly from a three-phase distribution transformer in two ways: by connection between one phase and neutral or by connection between two phases. These two give different voltages from a given supply.
The most popular are the 3 phase machines, where the windings are (electrically) 120° apart. [5] The 3-phase machines have major advantages of the single-phase ones: [6] steady state torque is constant, leading to less vibration and longer service life (the instantanous torque of a single-phase motor pulsates with the cycle)
The IE3 class will be mandatory from 1 January 2015 (7.5–375 kW) and 1 January 2017 (0.75–375 kW). [2] From June 1, 2021, three-phase motors from 0.75 kW to 1000 kW must meet at least IE3 efficiency. Electric motors from 0.12 kW to 0.55 kW must meet at least class IE2 efficiency. [3]