One basic method to reduce the starting current is with a reduced voltage autotransformer with taps at 50 %, 65 % and 80 % of the applied line voltage; once the motor is started the autotransformer is switched out of circuit.
42.
Unlike transformer-type baluns, autotransformer baluns connect all the wires connected to them to a single build-up of static electric charge, the path for the static to drain to ground through an autotransformer balun can be a distinct advantage.
43.
Unlike transformer-type baluns, autotransformer baluns connect all the wires connected to them to a single build-up of static electric charge, the path for the static to drain to ground through an autotransformer balun can be a distinct advantage.
44.
In 1959, Joel S . Spira, who would found the Lutron Electronics Company in 1961, invented a dimmer based on a diode and a tapped autotransformer, saving energy and allowing the dimmer to be installed in a standard electrical wallbox.
45.
For example, if the right-hand side is connected to a resistive load of 10 Ohms, the user can attach a source at any of the three ungrounded terminals on the left side of the autotransformer to get a different impedance.
46.
An autotransformer has a single winding with two end terminals, and one or more terminals at intermediate tap points, or it is a transformer in which the primary and secondary coils have part of, or all of their turns in common.
47.
If one of the center-taps is used for the ground, then the autotransformer can be used as a balun to convert a balanced line ( connected to the two end taps ) to an unbalanced line ( the side with the ground ).
48.
In North America and Japan however, the line voltage ( 120 V or 100 V respectively ) may not be sufficient to start lamps over 20 W with a series inductor, so an autotransformer winding is included in the ballast to step up the voltage.
49.
This would be more of a problem if the autotransformer were stepping down high voltage, as at a substation, than if it were stepping up low voltage, as at a generating station . talk ) 00 : 47, 17 November 2008 ( UTC)
50.
Where it is necessary to limit the starting inrush current ( where the motor is large compared with the short-circuit capacity of the supply ), the motor is started at reduced voltage using either series inductors, an autotransformer, thyristors, or other devices.
