Current limiting protective circuit for DC motor

Abstract

The invention relates to a current limiting protective circuit for a DC motor. The circuit includes a single-chip microcomputer unit, a driving unit, MOS switching tubes, sampling resistors and follow-current diodes. An output end of the single-chip microcomputer unit is connected with grid electrodes of the MOS switching tubes via the driving unit. Drain electrodes of the MOS switching tube are connected with a negative end of the DC motor M. A positive end of the DC motor M is connected with an anode of a DC power supply E. Source electrodes of the MOS switching tubes are connected with a cathode of the DC power supply E via the sampling resistors. The source electrodes of the MOS switching tubes are then connected with a sampling current input end of the driving unit. An overcurrent feedback signal output end of the driving unit is connected with an input end of the single-chip microcomputer unit. The follow-current diodes and the DC motor M are in reversed parallel connection. Through use of an electric device, after the motor stops operating because of an overly large load, a switch does not need to be restarted and only the load of the motor needs to be reduced and then the electric device is capable of re-operating; and the operation is convenient, the work efficiency is improved and the work continuity of the electric device is maintained.

Description

technical field [0001] The invention relates to a direct current motor, in particular to a current limiting protection circuit of the direct current motor. Background technique [0002] DC motors are used in many electrical appliances and electric equipment, but when the load increases, the DC motor will stall. For example, a lawn mower cuts smoothly when the grass is sparse. When the grass is densely cut, the motor load increases, and the stall phenomenon will occur. The motor will stop under the action of the ordinary overload protection circuit. Another example is a chain saw, which cuts smoothly when cutting thin wood. When cutting thick wood, the motor load increases, which will cause a stall phenomenon. The motor will stop under the action of an ordinary overload protection circuit. Therefore, the electric equipment using the above common overload protection circuits needs to restart the switch after the rotor is blocked before the machine can run. After the motor of...

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