JPS5915266B2 - DC device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a DC motor equipped with magnetic poles having commutating poles and series coils, and more particularly to a DC motor suitable for operation with a pulsating current power source.

FIG. 1 schematically shows a commutating pole section of a conventional DC machine.

A main pole consisting of a main pole iron core 2 and a series winding 6 provided on the yoke 1 is provided with a commutator core 3 and its commutator winding 5 in the neutral zone between the main poles.
A complementary pole consisting of is provided.

Note that 4 is an armature.

Figure 2 shows the wiring when operating such a DC machine with a pulsating current power source.

In the figure, the power source is converted into direct current by rectifying the current of an alternating current power source 7 with a rectifier 8 and smoothing it with a smoothing reactor 9.

This pulsating current power source is connected to a terminal in which an armature 4, a commutator winding 5, and a series winding 6 are connected in series.

A shunt resistor 10 is connected in parallel to the series winding 6 to suppress the pulsation of the main pole magnetic flux, and a series circuit consisting of a reactor 11, a contactor 12, and a weak field resistor 13 is connected in parallel. It is connected in parallel to the series winding 6.

Here, the contactor 12 and the like are provided for weak field control.

Now, as shown in Fig. 2, when a DC machine is operated with a pulsating current power source, a rectified magnetic flux is generated in the commutator winding 5 connected in series with the armature 4 by the armature current, but the rectified magnetic flux is There is a time delay with respect to the armature current.

Furthermore, the pulsation rate of the rectified magnetic flux is reduced relative to the pulsation rate of the armature current.

This relationship is shown in Fig. 3 as an example of armature current ■1
The rectified magnetic flux φ1 is delayed in time and the rectified magnetic flux φ1
As the pulsation rate becomes smaller, the rectified magnetic flux φ1 cannot sufficiently compensate for the change in the reactance voltage that occurs in the armature winding short-circuited by the brush, and the short-circuit current flowing through the brush increases, causing sparks. Rectification worsens.

In order to prevent this, conventional methods have been adopted in which the commutating magnetic circuit is constructed of laminated iron plates or by providing conductive plates on the side surfaces of the commutating pole core.

The former suppresses eddy currents in the block core, which cause a time delay in the rectified magnetic flux and a decrease in the pulsation rate, by constructing a yoke and a commutator core with laminated iron plates, thereby reducing the pulsating component of the rectified magnetic flux. This is a method to make it easier to pass.

Although this method is effective, since part or all of the yoke is made of laminated iron plates, its mechanical strength is weak and it is difficult to manufacture.

The latter method of providing a conductive plate suppresses approximately half of the rectified magnetic flux passing through the yoke side of the commutator core from leaking from the side surface of the commutator core, and the pulsating component of the rectified magnetic flux is prevented from leaking from the side of the commutator core. It is designed to pass through the gap between the

Although this method is also effective, it has the drawbacks that the eddy current flowing through the conductive plate causes loss, increases the temperature of the commutator winding, and makes it difficult to attach the conductive plate.

An object of the present invention is to provide a DC machine that is easy to manufacture and that can perform good rectification even when operated with a pulsating current power source with a high pulsating rate without using any special equipment.

According to the research conducted by the present inventors, it has been found that when a DC machine is operated with a pulsating current power source, the pulsating component of the rectified magnetic flux due to the interpolation is insufficient on the air gap side, resulting in poor rectification.

Therefore, in the present invention, as a means to eliminate the shortage of the pulsating component of the rectified magnetic flux, an auxiliary winding is provided separately from the commutating pole winding on the air gap side of the commutating pole, so that the auxiliary winding advances in time compared to the armature current. The shunt current of the series winding, which is a pulsating current, is passed through the auxiliary winding to reduce the time delay of the pulsating component of the rectified magnetic flux and further increase the pulsation rate.

Examples of the present invention will be described in detail below.

The difference between FIG. 4 and FIG. 1 is that the commutator core 3 has a 71D
Furthermore, the auxiliary winding 5a, which is connected in parallel with the series winding 6 via a resistor, is provided on the gap side between the armature 4 and the armature 4.

In this way, the auxiliary winding 5a is provided on the air gap side of the commutator core 3, and is connected in parallel with the series winding 6 via the resistor, so that the auxiliary winding 5a receives a portion of the armature current. flows, and the auxiliary winding magnetic flux generated at this time passes through the gap side of the commutator core 3 and enters the armature 4.

As a result, the armature winding short-circuited by the brushes is rectified and compensated by the combined magnetic flux of the rectified magnetic flux created by the commutator winding 50 and the auxiliary winding magnetic flux created by the auxiliary winding 5a.

Figure 5 shows the wiring when such a DC machine is operated with a single-phase full-wave rectified power supply.

Components that are the same as those in FIG. 2 or have the same functions are indicated by the same reference numerals.

A pulsating current power source is connected to a terminal where the armature 4, the commutator winding 5, and the series winding 6 are connected in series.

A series circuit consisting of an auxiliary winding 5a and a shunt resistor 10, and a series circuit consisting of a reactor 11, a contactor 12, and a weak field resistor 13 are connected in parallel to the series winding 6, respectively.

In the above wiring connection, when weak field control is not performed, the current 11 flowing through the auxiliary winding 5a is in phase with respect to the current 1 sK- flowing through the series winding 6 due to the series winding voltage V8, as shown in the vector diagram in FIG. progresses.

This is because in a DC series motor, when the magnetic flux generated by the current flowing through the series winding pulsates, a transformer electromotive force is generated in the armature winding short-circuited by the brush, and the short-circuit current due to the brush increases. 5 of the current in the series winding to prevent sparks from the brushes and worsening commutation.
Since the resistance value of the shunt resistor 10 is set so as to shunt a coefficient of % to 10, the ratio of the reactance to resistance of the series winding 6 is made up of the auxiliary winding 5a and the shunt resistor 10. This is because it is large compared to the ratio of circuit resistance to actance.

As a result, the DC component of the current flowing through the auxiliary winding 5a is approximately 5 to 10 times the armature current, and the pulsating current component is approximately 5 to 10 times the armature current.
Since a is provided on the gap side of the commutating pole, the reactance is sufficiently smaller than that of the series winding 6, so that the reactance is close to the magnitude of the pulsating component of the armature current.

Furthermore, as shown in FIG. 7, the pulsating current component 11 of the current flowing through the auxiliary winding 5a is advanced in phase compared to the pulsating current component i of the armature current.

As a result, the rectified magnetic flux, which is a combination of the rectified magnetic flux generated by the armature current flowing through the commutator winding 5 and the magnetic flux generated by the auxiliary winding 5a, has a small delay with respect to the armature current and has a large pulsation rate. It is possible to sufficiently rectify and compensate for changes in reactance voltage that occur in the armature winding due to current pulsations.

Next, a case will be described in which the contactor 12 is closed to perform weak field control.

The current 11 flowing through the auxiliary winding 5a is, as shown in FIG. The phase advances.

This means that the ratio of reactance to resistance of the circuit consisting of the auxiliary winding 5a and the shunt resistor 10 is the same as the ratio of reactance to resistance of the series winding 6 and the reactance of the reactor 11 and the weak field resistor 1.
This is because the ratio of reactance to resistance of the circuit consisting of 3 and 3 is small compared to the ratio of reactance and resistance.

Here, when a sudden change in the AC power supply I or a sudden change in the load occurs, the reactor 11 causes a counter electromotive force of the armature by flowing a changing current due to a sudden increase in the armature current to the series winding 6. It is provided for the purpose of increasing power, suppressing a sudden increase in armature current, and preventing deterioration of rectification, and the reactor 11 is set to a value close to the reactance of the series winding 6. It is often done.

Therefore, by passing a portion of the shunt current through the auxiliary winding 5aK, it is possible to reduce the time delay of the rectified magnetic flux with respect to changes in the armature current in the case of sudden fluctuations in the AC power supply 7 as described above, and as a result, the time delay of the rectified magnetic flux can be reduced. This results in good rectification.

As shown in FIG. 1, the phase of the current 11 in the auxiliary winding 5a is advanced compared to the pulsating component of the armature current i.

As a result, the rectified magnetic flux, which is a combination of the rectified magnetic flux generated by the armature current flowing through the commutator winding 5 and the magnetic flux generated by the auxiliary winding 5a, has a small delay with respect to the armature current and has a large magnitude. It is possible to sufficiently rectify and compensate for changes in reactance voltage that occur in the armature winding short-circuited by brushes due to current pulsations.

In this way, it is possible to improve the time delay and magnitude of the pulsating changes in the rectified magnetic flux synthesized with respect to changes in the armature current and pulsating current, thereby significantly improving the rectifying performance of DC machines operated with pulsating current power sources. can be improved.

As a result, there is no problem in operation with a power source having a large pulsating current rate, and a new effect is produced in that the smoothing reactor can be made smaller.

Furthermore, since the followability of the rectified magnetic flux is good even when the power supply or load suddenly changes, rectification during transient times and flashover resistance can also be improved.

As explained in detail above, the DC machine according to the present invention does not require any special equipment, is easy to manufacture, and can provide good rectification compensation even when operated with a pulsating current power source with a high pulsating rate. effective.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a commutating pole part of a conventional DC machine, Fig. 2 is a wiring diagram showing an example of a case where a conventional DC machine is operated with pulsating current,
Fig. 3 is a waveform diagram showing the armature current and rectified magnetic flux in a conventional DC machine, Fig. 4 is a sectional view showing the commutating pole part of the DC machine according to the present invention, and Fig. 5 is a waveform diagram showing the armature current and rectified magnetic flux in a conventional DC machine. A wiring diagram showing the case of operation, FIG. 6 is a vector diagram for explaining the auxiliary winding, series winding current, and armature current in the DC machine of the present invention, and FIG. 7 is a diagram showing the DC machine of the present invention. FIG. 6 is a vector diagram for explaining currents in an auxiliary winding, a series winding, a weak field shunt current, and an armature current when performing weak field control. 1...Yoke, 2...Main pole core, 3...Commuting pole core,
4... Armature, 5... Commutary winding, 5a... Auxiliary winding, 6... Series winding, 1... AC power supply, 8... Rectifier, 9... Smoothing reactor, 10... Shunt resistor, 11... Reactor, 12... Contactor, 13...
・Resistor for weak field.

Claims (1)

[Claims] 1. In a DC machine equipped with an armature, a commutating pole, a magnetic pole having a series winding coil, and a yoke, an auxiliary winding is provided on the air gap side of the commuting pole, and this auxiliary winding is connected to the series winding magnetic pole. A DC machine characterized by having the windings connected in parallel through a resistor.