Electricity: motive power systems – Nonrunning – energized motor
Patent
1989-01-30
1991-12-31
Smith, Jr., David
Electricity: motive power systems
Nonrunning, energized motor
318758, 187115, H02P 326
Patent
active
050775081
ABSTRACT:
A motor control method and apparatus for a hoist is disclosed in which a drive motor is connected to an adjustable frequency power supply in which the frequency of the power supplied to the motor can be selectively varied. At the initiation of a hoist operation, when the hoist brake is holding the motor and an object constituting a load on the motor stationary, power is supplied to the motor at a predetermined low frequency which is sufficient to provide load holding torque upon release of the brake. The actual current level of the power supplied to the motor is sensed at the initiation of the hoist operation and a signal representative of that current level is compared with a reference signal representative of a current level which is sufficient to provide the load holding torque. If the signal representative of the actual current level of the power supplied to the motor exceeds the reference signal, an output signal is provided which will result in the release of the hoist brake from its holding condition.
REFERENCES:
patent: 3244957 (1966-04-01), Spiess et al.
patent: 3331003 (1967-07-01), King
patent: 3486101 (1969-12-01), Rufli
patent: 4207508 (1980-06-01), Habisohn
patent: 4479565 (1984-10-01), Nomura
patent: 4503937 (1985-03-01), Cervenec et al.
patent: 4561073 (1987-03-01), Shimizu et al.
patent: 4681191 (1987-07-01), Ikejima
Hipp William A.
Wycoff David C.
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