JPS6029355Y2 - DC motor control circuit - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a control circuit for controlling the rotational direction of a DC motor.

A conventional device of this type is shown in FIG.

That is, the first one switches the voltage applied to the DC motor 3 by switching a pair of interlocking switches 1 and 2, as shown in FIG.

The second one is for switching the connection of a three-terminal DC power source 5 using one changeover switch 4, as shown in the figure.

Furthermore, the third one, as shown in FIG. It is something that can be switched.

However, the first type has the disadvantage of having a large number of changeover switches, the second type requires a special power source, and the third type has disadvantages such as large power loss due to the resistors 7 and 8.

The present invention has been devised in view of these points, and embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows one embodiment of the present invention. In this figure, S is a changeover switch, and its movable contact piece (2) is connected to one terminal (10B) of a DC power source (E).

A pair of changeover contacts A and B of changeover switch S and DC power supply E
A diode Da, a diode Da and a terminal B of the
Db and transistors Ta, series circuit La of Tb,
i and b are connected.

A DC motor M is connected between intermediate points P and Q of each series circuit.

The base of one transistor Ta is connected to the switching contact B via a resistor Ra, and the base of the other transistor Tb is connected to the switching contact A via a resistor Rb.

In the above configuration, when the movable contact piece V of the changeover switch S is in the neutral position as shown, the DC motor M is not supplied with power and does not rotate.

When the movable contact piece V is switched to the switching contact A, the transistor becomes conductive, and power is supplied to the DC motor M in the direction of the dashed arrow through the diode Da, so that the motor rotates in the normal direction.

At this point, the other transistor Ta is in a cutoff state because its base current is blocked by the diode Db.

When the movable contact V is switched to the other switching contact B, the transistor Ta becomes conductive, contrary to the above, so that power is supplied to the DC motor M in the direction of the solid arrow through the diode Db, and the motor rotates in reverse.

In this case, one transistor is in a cut-off state because its base current is blocked by the diode Da.

Next, FIG. 3 shows a modification of FIG. 2.

The difference is that the types of diodes Ta and Tb are different, and the connection positions of the transistors and diodes in each series circuit La and Lb are reversed. The point is that it was changed to .

However, since its operation is the same as that of the circuit shown in FIG. 2, its explanation will be omitted.

As described above, according to the configuration of the present invention, only one changeover switch is required, no special DC power source is required, and various drawbacks of conventional devices such as low power loss can be solved.

Furthermore, when a transistor in one series circuit is conductive, a diode connected in series with the transistor can block the base current of the transistor in the other series circuit, which greatly simplifies the control circuit.

[Brief explanation of drawings]

Figures 1a, b, and c are different control circuit diagrams of the conventional device,
FIG. 2 is an electric circuit diagram showing an embodiment of the control circuit according to the present invention, and FIG. 3 is a modified circuit diagram of FIG. 2. ■...Movable contact piece, E...DC power supply, 10B, -B...terminal, S...changeover switch, A, B... ...Switching contact, Da, Db...
...Diode, Ta, Th...Transistor, La, tb...Series circuit, P, Q...
...Middle point, M...DC motor.

Claims (1)

[Scope of utility model registration request] A series circuit of a diode and a transistor is inserted between a pair of switching contacts of a changeover switch whose movable contact piece is connected to one terminal of a DC power supply and the other terminal of the DC power supply, and a DC current is inserted between the intermediate points of each series circuit. A control circuit for a DC motor, wherein a motor is connected, and bases of transistors of the one series circuit are connected to the switching contacts connected to the other series circuit.