Search results
Results from the WOW.Com Content Network
In circuit design, the Y-Δ transform, also written wye-delta and also known by many other names, is a mathematical technique to simplify the analysis of an electrical network. The name derives from the shapes of the circuit diagrams , which look respectively like the letter Y and the Greek capital letter Δ .
For large motors also the star-delta starter cannot be used, especially if they are started with a significant load. The circuit has advantage over starting with a regular autotransformer, which needs to be at some point completely disconnected during the start inducing high voltage impulses, which can damage the electrical insulation of the ...
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'). A wye system allows the use of two different voltages from all three phases , such as a 230/400 V system which provides 230 V between the neutral (centre hub) and any one of the phases, and 400 V ...
During starting condition stator winding is connected in the form of a star. Now we shall see how a star delta starter reduces the starting current of a three-phase induction motor. [7] The above function achieved by using a power contactor and timer in automatic star delta starter. The automatic star delta starter is manufactured from three ...
Inrush current, input surge current, or switch-on surge is the maximal instantaneous input current drawn by an electrical device when first turned on. Alternating-current electric motors and transformers may draw several times their normal full-load current when first energized, for a few cycles of the input waveform.
The delta winding allows third-harmonic currents to circulate within the transformer, and prevents third-harmonic currents from flowing in the supply line. [2] Delta-wye transformers introduce a 30, 150, 210, or 330 degree phase shift. [3] Thus they cannot be paralleled with wye-wye (or delta-delta) transformers.
Self-starting polyphase induction motors produce torque even at standstill. Available squirrel-cage induction motor starting methods include direct-on-line starting, reduced-voltage reactor or auto-transformer starting, star-delta starting or, increasingly, new solid-state soft assemblies and, of course, variable frequency drives (VFDs). [39]
A motor soft starter is a device used with AC electrical motors to temporarily reduce the load and torque in the powertrain and electric current surge of the motor during start-up. This reduces the mechanical stress on the motor and shaft, as well as the electrodynamic stresses on the attached power cables and electrical distribution network ...