An automotive electrical system with a generator has outputs for loads requiring a high and low voltage, e.g., a heater and a battery. A field-controlled a.c. generator with three-phase output windings has a low voltage main terminal and an auxiliary terminal for high voltage loads. A step-down transformer and a first rectifier connect the windings and the main terminal while a second rectifieer directly connects the windings and the auxiliary terminal. A selector switch having a open and closed positions is connected between the main terminal and the auxiliary terminal. A voltage regulator for controlling current through the generator field is connected to the main terminal. When the selector switch is open the generator provides a dual voltage output i.e., a high voltage level at the auxiliary terminal and a low voltage level at the main terminal; in the closed position of the switch the regulator is connected to the auxiliary terminal and reduces the generator output thereof to said low voltage level while the output of the first rectifier is reduced to an ineffective level, due to the step-down effect of the transformer. The selector switch thus controls the generator output between a dual voltage output (switch open) and a low voltage output (switch closed).

High/low DC voltage motor vehicle electrical system

A supplementary heating system particularly suitable for an automotive vehicle comprises a step down transformer coupled to the stator windings of the vehicle's alternator and a positive temperature coefficient (PTC) of resistivity heater electrically connected intermediate the stator windings and the transformer in parallel with the transformer. Due to the presence of the transformer the voltage regulator causes the alternator to operate at a higher than customary voltage to provide the conventional 14.4 volts for the vehicle's normal electrical loads with the high voltage used to energize the heater. The heater can be in the form of a so-called "honeycomb" having a plurality of parallely extending passages or cells disposed in the air stream going from the main heater into the passenger compartment and can be either a multiphase, single phase or direct current type. In one embodiment the transformer is switched into and out of electrical coupling with the alternator dependent on the energization of the heater, while in another embodiment the transformer is always electrically coupled to the alternator with the heater switched into and out of the circuit as desired.

Supplemental automotive vehicular heater system and method of providing same

A high DC voltage power supply includes a three-phase autotransformer and a three-phase full-wave rectifier applied to the usual motor vehicle electrical system of the low DC voltage type. The low three-phase AC voltage of the usual system is transformed by the autotransformer to obtain a high three-phase AC voltage which is then rectified by the rectifier to provide a high DC voltage. The load energized by the high DC voltage is ungrounded to reduce the voltage available for inadvertent discharge from either load terminal to ground. Switching apparatus is provided for selectively applying the low three-phase AC voltage to the autotransformer only when it is desired to energize the load thereby avoiding at all other times the energy losses that would otherwise be associated with energization of the autotransformer. In one embodiment, the load is a windshield heater element and the autotransformer has multiple sets of input taps to provide deice and defog modes of operation, respectively. The tapping of the autotransformer on the input or primary side yields efficiencies in the construction and operation of the autotransformer. The engine driven generator of the vehicle electrical system is excited from a voltage source independent of the low three-phase AC voltage put out by the generator, at least during any period that the generator is overloaded, thereby to prevent a degenerative collapse in the generator output voltage.

High DC voltage power supply for motor vehicle electrical system

A generator system in accordance with the invention has two modes of operation, such as 120 VAC and 240/120 VAC modes of operation. The generator system has a permanent magnet generator with two independent sets of windings that each generate a three phase AC voltage. One three phase AC voltage is coupled to a first or master cycloconverter and the second three phase AC voltage is coupled to a second or slave cycloconverter. Live outputs of each cycloconverter are coupled to each other through a switch, such as a relay and neutral outputs of each cycloconverter are coupled to ground. A controller controls the cycloconverters to provide a first voltage, illustratively 120 VAC, across their respective outputs having the same amplitude. When in the 120 VAC mode, the switch across the live outputs of the first and second cycloconverters is closed, shorting the live outputs of the first and second cycloconverters together and the controller operates the first and second cycloconverters so their output voltages are in phase with each other. When in the 240/120 VAC mode, the switch across the live outputs of the first and second cycloconverters is open and the controller operates the first and second cycloconverters so that their output voltages are 180 degrees out of phase. The permanent magnet generator has rotor position sensors that are used by a brushless DC motor drive to drive the permanent magnet generator as a brushless DC motor to start the engine of the generator system and also to develop cosine wave information for use in controlling the cycloconverters.

Generator with dual cycloconverter for 120/240 vac operation

Winding arrangement of a stator and/or rotor of a three-phase generator or electromotor makes possible an improvement of all performances of these electric machines. The improvement is obtained in that to star-connected windings (1, 2, 3) there are connected additional delta-connected windings (4, 5, 6), which in relation to the star-connected windings (1, 2, 3) are spatially shifted for an angle of , p being the number of pole pairs. Such a winding arrangement is symbolically expressed by: Y + j Δ =

Winding arrangement of a stator and/or rotor of a three-phase generator or electromotor with improved performances

To provide a-c output at a voltage substantially higher than normal automotive voltage of 12-24 V, for example output voltage in the 80 to 90 V range to operate windshield and other glass pane heaters, a three-phase alternator is star-connected and has two armature windings which, for example, may be serially connected or may be separately wound, on the same stator, one winding being of comparatively few turns of heavy wire and connected to a rectifier to provide normal d-c on-board voltage for the vehicle, stored in a battery, the voltage being controlled by a voltage regulator connected to the d-c output terminals; the other winding, for example of a much larger number of turns of finer wire providing the high-voltage output at terminals adapted for connection to the heater wires in the windshield, or rear windows, or other window panes.

Yoriaki Iwata

Papers

Double-voltage, automotive-type alternator