Automatic electrical motor speed control
US4481448A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 1, 1983 |
| Grant date | Nov 6, 1984 |
| Priority date | — |
| Expiry date | Jul 1, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P25/145
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An automatic speed controller for a universal, series-wound, electrical motor, is part of a system whereby the motor is energized by a A.C. supply from control means including a triac, in turn, controlled by the speed controller. Within the controller signals are derived comprising solutions of the equation: ##EQU1## or a derivative thereof, or an approximation thereof, where N is the armature speed, R.sub.a is the resistance of the armature, K is a constant dependent upon the motor design, (V.sub.a -I.sub.a R.sub.a) is the true average of the alternating quantity (v.sub.a -i.sub.a R.sub.a), where v.sub.a and i.sub.a are, respectively, the instantaneous armature voltage and current, and .0..sub.AV is the true average flux in the magnetic circuit of the motor, both true averages being obtainable when the motor is operating under steady state conditions. Each derived signal is compared with a reference signal representative of the required armature speed, and any error signal, so provided, is caused to vary the average energy supplied to the motor in consecutive half cycles of the motor supply, so as to tend to reduce the error.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.