Circuit arrangement for controlling the operation of an electric motor supplied from an inadequately regulated DC voltage source

摘要

The circuit arrangement is used for starting the motor, which is connected to the DC voltage source via a contactor, which source may be a battery. A drop in the battery voltage below a value which is no longer adequate for reliable operation of the motor is sensed by a first circuit part (TR10, TR11) and a second circuit part (TR9) is triggered in order to charge a capacitor (C5). The capacitor charge enables a relay (RLA4) to trip in order to isolate the motor from the battery. Furthermore, the charge of the capacitor enables renewed starting of the motor to be delayed during a subsequent rise in the battery voltage. In consequence, there is no rapid motor starting-switching cycle, which could result in the contactor and possibly also the motor being damaged. <IMAGE>