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In electrical engineering, three-phase electric power systems have at least three conductors carrying alternating voltages that are offset in time by one-third of the period. A three-phase system may be arranged in delta (∆) or star (Y) (also denoted as wye in some areas, as symbolically it is similar to the letter 'Y').
If two motors with the same and torque work in tandem, with rigidly connected shafts, the of the system is still the same assuming a parallel electrical connection. The K M {\displaystyle K_{\text{M}}} of the combined system increased by 2 {\displaystyle {\sqrt {2}}} , because both the torque and the losses double.
An important class of three-phase load is the electric motor. A three-phase induction motor has a simple design, inherently high starting torque and high efficiency. Such motors are applied in industry for many applications. A three-phase motor is more compact and less costly than a single-phase motor of the same voltage class and rating, and ...
The motor accelerates from slip speed to synchronous speed during an accelerating half cycle of the reluctance torque. [3] Single-phase synchronous motors such as in electric wall clocks can freely rotate in either direction, unlike a shaded-pole type. Costs are an important parameter for starters. [38]
Direct torque control (DTC) is one method used in variable-frequency drives to control the torque (and thus finally the speed) of three-phase AC electric motors.This involves calculating an estimate of the motor's magnetic flux and torque based on the measured voltage and current of the motor.
In the power systems analysis field of electrical engineering, a per-unit system is the expression of system quantities as fractions of a defined base unit quantity. . Calculations are simplified because quantities expressed as per-unit do not change when they are referred from one side of a transformer to t
Symmetrical components are most commonly used for analysis of three-phase electrical power systems. The voltage or current of a three-phase system at some point can be indicated by three phasors, called the three components of the voltage or the current. This article discusses voltage; however, the same considerations also apply to current.
This assumes that the electrical generator converts 90% of the engine's output into electrical energy and the traction motors convert 90% of this electrical energy back into mechanical energy. [citation needed] Calculation: 0.9 × 0.9 = 0.81 Individual traction motor ratings usually range up 1,600 kW (2,100 hp).