Title:
CONTROLLER FOR INDUCTION MOTOR
Document Type and Number:
Japanese Patent JPS6084989
Kind Code:
A
Abstract:
Many induction motor controllers employ a reference angle relative to the supply voltage which is a target for the phase lag of current behind voltage but the choice of the optimum reference angle for energy saving varies from motor to motor. In the present invention firing signals for thyristors (10, 11) connected between a supply and a motor to be controlled are generated by firing circuits (21, 22, 23) under the control of a microprocessor 18. The firing angle for the thyristors is continuously adjusted according to the phase lag as indicated by supply voltage zero crossings (sensed by a gate 20) and current sensing circuits (12), load on the motor, and a signal indicating the tendency of the motor to stall obtained from the back e.m.f. of the motor. Using the said signal can be regarded as equivalent to adjusting the reference angle for the optimum value mentioned above. A procedure for starting a motor and setting the initial value of the reference angle is also described.
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| WO/1997/007589 | PROCESS AND DEVICE FOR OPERATING AN ASYNCHRONOUS MOTOR |
Inventors:
PIITAA JIYOSEFU ANSUWAASU
Application Number:
JP19379284A
Publication Date:
May 14, 1985
Filing Date:
September 14, 1984
Export Citation:
Assignee:
NAT RES DEV
International Classes:
H02P1/26; H02P23/00; H02P27/02; (IPC1-7): H02P1/26; H02P7/36
Domestic Patent References:
| JPS56150995A | 1981-11-21 | |||
| JPS57166894A | 1982-10-14 |
Attorney, Agent or Firm:
Minoru Nakamura (6 outside)
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