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The circle diagram can be drawn for alternators, synchronous motors, transformers, induction motors. The Heyland diagram is an approximate representation of a circle diagram applied to induction motors, which assumes that stator input voltage, rotor resistance and rotor reactance are constant and stator resistance and core loss are zero.
The curve is obtained by rotating the generator at the rated RPM with the output terminals disconnected and the output voltage typically going to at least 120% of the rated for the device. The hydraulic units sometimes have to be tested at lower RPM with the resulting voltage scaled up to accommodate the differences in frequency.
As an example, consider the use of a 10 hp, 1760 r/min, 440 V, three-phase induction motor (a.k.a. induction electrical machine in an asynchronous generator regime) as asynchronous generator. The full-load current of the motor is 10 A and the full-load power factor is 0.8. Required capacitance per phase if capacitors are connected in delta:
Early automobile generators and alternators had a mechanical voltage regulator using one, two, or three relays and various resistors to stabilize the generator's output at slightly more than 6.7 or 13.4 V to maintain the battery as independently of the engine's rpm or the varying load on the vehicle's electrical system as possible.
The field current is much smaller than the output current of the alternator; for example, a 70 A alternator may need only 2-3 A of field current. The field current is supplied to the rotor windings by slip rings. The low current and relatively smooth slip rings ensure greater reliability and longer life than that obtained by a DC generator with ...
Capability curves for generators with full converters: D-shape (red), rectangular (green), triangular (blue) The inverter-based resources (like solar photovoltaic (PV) generators, doubly-fed induction generators and full-converter wind generators, also known as "Type 3" and "Type 4" turbines [5]) need to have reactive capabilities in order to contribute to the grid stability, yet their ...
The rotating parts of a turbo generator are subjected to high mechanical stresses because of the high operation speed. To make the rotor mechanically resistant in large turbo-alternators, the rotor is normally forged from solid steel and alloys like chromium-nickel-steel or chromium-nickel-molybdenum are used. The overhang of windings at the ...
Single-phase generator (also known as single-phase alternator) is an alternating current electrical generator that produces a single, continuously alternating voltage. Single-phase generators can be used to generate power in single-phase electric power systems.