Patent · US Expired

Motor control system, particularly to reduce idling speed

US4002959A · kind A · utility

24Cited by

5References

12Claims

0Family size

Assignee

Robert Bosch GmbH · DE

Inventors

Fritz Schadlich · Echterdingen, DE
Friedrich Hornung · Stuttgart, DE

Key dates

Filing date	Jan 28, 1975
Grant date	Jan 11, 1977
Priority date	—
Expiry date	Jan 28, 1995

Classification

Technology area (CPC H)Electricity
CPC primaryH02P25/14
WIPO fieldElectrical machinery, apparatus, energy
WIPO sectorElectrical engineering

Abstract

To reduce noise and idling speed of electric motors, particularly series motors, the speed-torque characteristic of the motor is dropped with respect to the loaded speed-torque characteristic, by sensing no-load operation of the motor and deriving a sensed signal, the sensed signal being applied to controlled switches to abruptly change the effective voltage applied to the motor between values corresponding to the no-load speed-torque characteristic, or the load speed-torque characteristic and resulting in the desired speed, in dependence on the value of the sensed signal. Preferably, the operating condition of the motor is sensed by an inductive transducer, and a speed change is obtained by phase control, or half-wave rectification.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.