Patent US3908156A successfully refreshed from Google Patents.
US3908156A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Induction motor speed control apparatus
Assignee: Mitsubishi Electric Corp
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Filing: 1973-12-18
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Granted: 1975-09-23
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Expires: 1993-12-18
Abstract
Abstract An Apparatus for controlling the speed of an induction motor is disclosed wherein a voltage is applied to the motor according to a difference signal between a signal corresponding to the speed of a load and a preset speed command signal, thereby causing the motor to produce a rotating torque corresponding to the difference signal. When the load is driven at a maximum speed, a rated voltage is applied to the motor. The apparatus comprises a device capable of presetting, prior to decelerating the load, a signal necessary to allow the motor to produce a rotating torque corresponding to the load. At the beginning of the load deceleration, a voltage corresponding to the preset signal of the device is applied to the motor.
Inventors
- 👤 Nobuo Anzai
- 👤 Hiroshi Kamaike
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:23
CPC Classifications
H; H02; H02P; H02P27/00; H02P27/02; H02P27/026; B; B66; B66B; B66B1/00; B66B1/24; B66B1/28; B66B1/30; B66B1/308
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
162 words
Apparatus for controlling the speed of an induction motor comprising: means for generating a preset command signal corresponding to the desired speed of the motor; means for generating a first signal corresponding to the speed of the load of the motor; means for generating a difference signal corresponding to the difference between the first signal and the preset command signal; means for applying the difference signal to the motor to cause the motor to produce a rotating torque corresponding to the difference signal; means for applying a rated voltage to the motor when the load is driven at its maximum speed; means for presetting, prior to the deceleration of the load, a second signal corresponding to the load torque of the motor; means for applying the second signal to the motor at the beginning of the deceleration of the load to prevent a discontinuity in the rotating torque of the motor during the time the motor is decelerated from its maximum speed.
Claim 2
Dependent Claim
162 words
Apparatus for controlling the speed of an induction motor comprising: means for generating a preset command signal corresponding to the desired speed of the motor; means for generating a first signal corresponding to the speed of the load of the motor; means for generating a difference signal corresponding to the difference between the first signal and the preset command signal; means for applying the difference signal to the motor to cause the motor to produce a rotating torque corresponding to the difference signal; means for applying a rated voltage to the motor when the load is driven at its maximum speed; means for presetting, prior to the deceleration of the load, a second signal corresponding to the load torque of the motor; means for applying the second signal to the motor at the beginning of the deceleration of the load to prevent a discontinuity in the rotating torque of the motor during the time the motor is decelerated from its maximum speed.
Claim 3
Dependent Claim
38 words
Apparatus for controlling the speed of an induction motor in accordance with claim 1 further comprising: means for disconnecting the means for applying a rated voltage to the motor at the beginning of the deceleration of the load.
Claim 4
Dependent Claim
27 words
Apparatus for controlling the speed of an induction motor in accordance with claim 2 wherein the means for presetting the second signal comprises amplification factor changing device.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-22 | 1979-03-24 | 1979-09-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-22 | 1983-03-24 | 1983-09-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-22 | 1987-03-24 | 1987-09-23 | $7700.00 | Window Closed / Lapsed |