JPS6216800Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention aims to provide a dual-voltage commutator motor that can be used in both high-voltage and low-voltage areas. Conventionally known methods for making a commutator motor usable in both high and low voltage regions include a chi-yoke method and a stator winding connection switching method. In the chi-yoke method, the voltage is reduced by a chi-yoke so that the voltage applied to the motor is the same even if the power supply voltage is different, but it is expensive because it requires a chi-yoke, and it takes up a lot of space to install the chi-yoke. It becomes necessary. Further, the stator winding connection switching method has the advantage of being relatively inexpensive, but has the disadvantage that it is inefficient in high voltage areas and has poor workability due to an increase in the amount of windings in the motor. That is, according to this method, normally in high voltage areas, four stator windings 1, 2, 3, and 4 are connected in series as shown in Figure 1, and in low voltage areas, two stator windings are connected in series as shown in Figure 2. While connecting windings 2 and 3 in parallel,
The other two stator windings 1 and 4 are left idle. Therefore, in high voltage areas, the ratio of the ampere turns of the field winding to the ampere turns of the armature winding, that is, the winding ratio, becomes too large, and as can be seen in Figure 4, there is a disadvantage that the efficiency of the motor decreases. . Furthermore, since four stator windings are connected, the number of windings increases, and two windings are left idle in low voltage regions, resulting in poor winding utilization. Furthermore, since the commutator motor rotates even when a half-wave voltage is applied, it is conceivable to apply a full-wave voltage in low-voltage areas and to rotate with a half-wave voltage by connecting a diode in high-voltage areas. However, when operating at half-wave voltage, there is a drawback that torque vibration is large, knocking vibration may occur, and brush wear increases. That is, when a commutator motor is operated with alternating current voltage, the voltage generated in the coil short-circuited by the brushes is composed of the reactance voltage self-induced by the change in current, and the rectification generated because the short-circuited coil cuts the magnetic flux. It is the vector sum of the electromotive force and the transformer electromotive force generated in the shorted coil because the field magnetic flux changes every 50 or 60 cycles, and this voltage rectifies the rate of change of the current flowing in the shorted coil. The brush position is set so that it becomes negative or small at the end of the cycle. However, when operating at a half-wave voltage, the current in the short-circuited coil changes greatly, and the reactance voltage increases, deteriorating the rectification conditions and increasing wear on the brushes. Therefore, this proposal connects a bidirectional control rectifier element in high voltage areas and applies an AC voltage whose phase angle is controlled by the element to the motor, thereby preventing a decrease in motor efficiency and at the same time preventing brush wear. We also aim to reduce this. The present invention will be explained below based on Fig. 3. 5 is a rotor of a commutator motor with armature windings 6 and 7 connected to form two parallel circuits, and one brush 8 is connected to the power supply 9 side. However, the other brush 10 is directly connected to one fixed contact 12 in the changeover switch 11 and also connected to another fixed contact 14 via a field winding 13. The changeover switch 11
In addition to these fixed contacts 12 and 14, there are two fixed contacts 15 and 16 inside, and the fixed contacts 12, 15, and 14 are connected by two movable contact pieces 17 and 18 that interlock with each other. 16 can be switched. Reference numeral 19 denotes another field winding of the commutator motor, which is connected between the two movable contact pieces 17 and 18, and has one end connected to the power source 9 side. Reference numeral 20 denotes a bidirectional control rectifier element connected between one end of the winding 13 and the fixed contact 15, and connected between a semi-fixed resistor 22 and a capacitor 23 via a diode 21. 24 is a capacitor for preventing malfunction. The operation of the above configuration will be explained. When used in a low voltage area, for example, a 110V area, the movable contacts 17 and 18 of the changeover switch are inserted into the fixed contacts 12 and 14 as shown by the solid lines. Then, since the two field windings 13 and 19 are connected in parallel, the voltage drop in the field windings is reduced, resulting in a connection suitable for low voltage operation. When used in a high voltage area, for example, a 220V area, move the movable contacts 17 and 18 to the fixed contact 1 as shown by the dotted line.
Put it on the 5, 16 side. Then, the rotor 5, field windings 13, 19, and bidirectional control rectifying element 20 are connected in series. When the power supply voltage is applied in this state, the capacitor 24 is charged every half cycle, and when it reaches a predetermined voltage, the diode 21 becomes conductive and current flows to the control pole of the bidirectional control rectifying element 20, which becomes conductive. When used in areas with double voltage, the field windings 13 and 1 can be adjusted by adjusting the semi-fixed resistor 22 so that the phase delay until conduction is 90°.
9 can remain in parallel, but if you do it like this,
The wear of the brush increases for the same reason as when using a diode. From the viewpoint of brush wear, it is desirable that the voltage drop due to the bidirectional control rectifying element 20 is 40% or less, and the voltage drop due to the bidirectional control rectifying element 20 is preferably 40% or less.
As a result of experiments, it was found that it is desirable to connect 9 in series to reduce the drop. According to another experiment, as shown in Fig. 5, when the ratio of the ampere turns of the field windings 13 and 19 to the ampere turns of the armature windings 6 and 7, that is, the winding ratio, was less than 0.8, the brushes were significantly worn. Become. Also the fourth
As shown in the figure, when the ratio becomes 2.5 or more, the efficiency of the motor deteriorates. Therefore, when the series winding N of the field windings 13 and 19, the number of windings in one of the armature windings 6 and 7 is N', and the current flowing through the whole is I, when using high voltage,

[Formula] When using low voltage

It is necessary that [Formula]. From both equations, it is necessary that 0.8N'<N<1.25N'. As described above, in high-voltage areas, this proposal reduces the voltage by both the multiple field windings connected in series and the bidirectional control rectifier, so the voltage is reduced only by the bidirectional control rectifier. It does not worsen the rectification effect and increase wear on the brushes as it does when dropping the field windings. Thus, the ratio of the ampere turns of the field winding to the ampere turns of the armature winding, that is, the winding ratio, does not become too large and reduce the efficiency of the motor.

[Brief explanation of the drawing]

FIGS. 1 and 2 are circuit diagrams of a conventional commutator motor. FIG. 1 shows the circuit when a high voltage is used, and FIG. 2 shows the circuit when a low voltage is used. Figure 3 is a circuit diagram of the proposed commutator motor.
FIGS. 4 and 5 show changes in motor efficiency and brush wear rate with respect to winding ratio, respectively. 13, 19... Field winding, 20... Bidirectional control rectifier, 6, 7... Armature winding.

Claims (1)

[Claims for Utility Model Registration] (1) In a commutator motor used in areas with different voltages, multiple field windings are connected in parallel in low voltage areas, and in high voltage areas, A two-voltage commutator motor comprising equal field windings connected in series and a bidirectional control commutator connected in series with the field windings. (2) A two-voltage commutator motor configured to drop a voltage of 40% or less of the power supply voltage by a bidirectional control rectifier as claimed in claim 1 of the utility model registration. (3) In claim 1 of the utility model registration claim, the number of parallel circuits of the field winding and armature winding during low voltage use is two each, and the number of series windings of each winding is two. When N, N′, 0.8N′<N<
A two-voltage commutator motor characterized by a 1.25N′.