Universal motor control system

Claim 1

In a system requiring motor control at multiple speed levels and power supply to an isolated low voltage control circuit (60), an auto-transformer coil (41) having at least first, second and third tapping points (11, 12, 13) formed thereon, said tapping points corresponding to levels of 110 percent, 100 percent and 90 percent of an available power supply line voltage (L2), first line means (81) extending from said first auto-transformer tapping point (11) for attachment to and receipt of power from a terminal block (80) when a power supply (L2) of 230 V/50 Hz is encountered, second line means (82) extending from said second auto-transformer tapping point (12) for attachment to and receipt of power from a terminal block (80) when a power supply (L2) of 230 V/60 Hz or 208 V/50 Hz is encountered, third line means (83) extending from said third auto-transformer tapping point (13) for attachment to and receipt of power from a terminal block (80) when a power supply (L2) of 208 V/60 Hz is encountered, a motor control unit (10) which contains said auto-transformer coil (41) and at least first, second and third remote tapping points (22, 23, 24) formed as a part of said motor control unit, a first line means (31) for conveyance of high speed motor voltage from said first remote tapping point (22), a second line means (32) for conveyance of medium speed motor voltage from said second remote tapping point (23), a third line means (33) for conveyance of low speed motor voltage from said third remote tapping point (24), switch means (52, 53, 54) for conveying a desired power level to a line (51) to a motor (70) to be run at differing speeds, wherein said motor control unit (10) further includes a secondary transformer coil means (42) for supply of low voltage power to a low voltage control circuit (60).