JPS6214994U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a conventional example, and FIG. 2 is a circuit diagram showing an embodiment of the present invention. Explanation of symbols of main parts, 2...DC motor, 3
...first current control element, 4...second current control element, 5...voltage relay means.

Claims (1)

[Scope of utility model registration request] A DC motor constant speed drive device using a proportional current control method that drives the DC motor while keeping the rotational speed constant, and a first current control element that is connected in series to the DC motor and controls the current according to a control signal. and,
a reference voltage generation series circuit in which a voltage detection resistor, a constant voltage source, and a constant current source are connected in series in order, and a voltage at a connection point between the constant voltage source and the constant current source is used as a reference voltage;
A DC power supply that supplies DC voltage to both ends of the series circuit of the DC motor and the first current control element and the reference voltage generation series circuit, and a current that is connected between the terminals of the DC power supply according to the control signal. a series circuit of a second current control element and a proportional resistor that performs control; a comparator that compares a voltage at a connection point between the DC motor and the first current control element with the reference voltage and generates the control signal; A DC motor constant speed drive device comprising voltage relay means for relaying a voltage at a connection point between the proportional resistor and the second current control element to a connection point between the voltage detection resistor and the constant voltage source. .