JP3335797B2 - Electric motor braking device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor braking device and, more particularly, to a motor braking device which does not cause burnout of the motor even when the contacts of switches in a circuit are welded.

[0002]

2. Description of the Related Art An example of a motor braking device using a double-pole double-throw switch for switching between operation and braking is disclosed in Japanese Utility Model Laid-Open Publication No. 52-147222. FIG. 2 shows an electric motor braking device according to this conventional example. In FIG. 2, the double-pole double-throw switch 25 includes a first double-throw switch 26 and a second double-throw switch 27 that are linked to each other. First
The double throw switch 26 includes a movable contact 26a, a first fixed contact 2
6b and a second fixed contact 26c, and the second double throw switch 27 includes a movable contact 27a, a first fixed contact 27b, and a second fixed contact 27c. AC power supply 29 is input terminal 2
The voltage is applied between 8a and 28b. One input terminal 28
a, the first of the single pole switch 24 and the first double throw switch 26
The fixed contact 26b is connected in series, and the other input terminal 28
b, the field coil 22 and the first fixed contact 27b of the second double throw switch 27 are connected in series. Further, the other input terminal 28b is connected to a second fixed contact 27c of the second double throw switch 27.

The rotating armature 21 of the electric motor includes movable contacts 26a, 27a of first and second double throw switches 26, 27.
The braking resistor 23 is connected between the second fixed contact 26 c of the first double throw switch 26 and the first fixed contact 27 b of the second double throw switch 27. During operation, the single-pole switch 24 is closed as shown by a solid line, and in the first and second double-throw switches, the movable contacts 26a and 27a are respectively connected to the first fixed contacts 26b and 27b as shown by a solid line. At this time, the armature 21 and the field coil 22 are connected in series and supplied with power from an AC power supply 29, so that the armature 21 rotates. Next, at the time of dynamic braking, the single pole switch 24 opens as shown by the dotted line, and the first and second double throw switches
The movable contacts 26a, 27a are connected to the second fixed contacts 26c, 27c, respectively, as shown by the dotted lines. At this time, the armature 21 and the field coil 22 are disconnected from the AC power supply 29, and the armature 21, the braking resistor 23 and the field coil 22
Forms a closed circuit. For this reason, the electric power generated by the rotating armature 22 is consumed by the braking resistor 23 while exciting the field coil 22.
Is subjected to dynamic braking.

[0004]

However, if welding occurs at the contacts of each switch, the following inconvenience occurs. For example, when the movable contact 27a and the second fixed contact 27c of the second double throw switch 27 are welded, the AC power supply 29 is directly applied only to the armature 21 when the switch is set to the operation position. , A large current flows, and the armature 21 is burned. Also, when welding of the single-pole switch 24 and welding of the movable contact 26a and the first fixed contact 26b of the first double throw switch 26 occur, the AC power supply 29 is directly connected to the armature when the switch is set to the braking position. Since the voltage is applied only to the armature 21, a large current flows through the armature 21, and the armature 21 is burned. Accordingly, an object of the present invention is to provide a braking device for an electric motor that eliminates the above-mentioned disadvantages and does not burn out the armature or the like of the electric motor even when the contacts of the switch are welded.

[0005]

In order to solve the above-mentioned problems, a configuration of the present invention comprises an electric motor having an armature and a field coil, and a first opening / closing section and a second opening / closing section which operate in opposite directions. A first double-throw switch, a second double-throw switch having a third opening / closing section and a fourth opening-and-closing section that operate in opposite directions, and a single-pole switch; , An armature, a single-pole switch, a field coil, and a third opening / closing section of the second double-throw switch are sequentially connected in series, and during braking, the second opening-closing section of the first double-throw switch; The first double-throw switch, the second double-throw switch, and the single-pole switch are controlled such that the field coil, the fourth opening / closing section of the second double-throw switch, and the armature are connected in series. Is a braking circuit of the electric motor.

[0006]

According to the configuration of the present invention, during operation, the single-pole switch is closed, and the first and third switching units are closed and the second and fourth switching units are opened in the first and second double-throw switches. Power is applied to the series circuit of the armature and the field coil. On the other hand, at the time of dynamic braking, the single-pole switch is opened, the first and third switching units are opened in the first and second double-throw switches, and the second and fourth switching units are closed. The element and the field coil form a closed loop. Here, even when welding occurs at any of the contacts of the single-pole switch, the first double-throw switch, and the second double-throw switch, the AC power may be applied only to either the armature or the field coil. Since there is none, it is possible to prevent the armature or the field coil from burning.

[0007]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a circuit of an AC series commutator motor with a braking circuit according to one embodiment of the present invention. In FIG. 1, a double pole double throw switch 13 is a first double throw switch 1
4 and a second double throw switch 15. The first double throw switch 14 includes a movable contact 14a, a first fixed contact 14b, and a second fixed contact 14c, and the movable contact 14a selectively contacts either the first fixed contact 14b or the second fixed contact 14c. I do. Movable contact 14a and first fixed contact 14
b constitutes a first opening / closing section 14x, and the movable contact 14a and the second fixed contact 14c constitute a second opening / closing section 14y. For this reason, the first opening / closing section 14x and the second opening / closing section 14y operate in opposite directions, and when the first opening / closing section 14x is closed, the second opening / closing section 14y opens, and the first opening / closing section 14x opens. The second opening / closing part 14y is closed.

The second double throw switch 15 has a movable contact 15
a, the first fixed contact 15b and the second fixed contact 15c, and the movable contact 15a is the first fixed contact 15b or the second fixed contact 15b.
Alternatively, it contacts one of the fixed contacts 15c. The third opening / closing portion 15x is formed by the movable contact 15a and the first fixed contact 15b.
The movable contact 15a and the second fixed contact 15c constitute a fourth opening / closing section 15y. For this reason, the third opening / closing section 1
5x and the fourth opening / closing section 15y operate in the opposite directions to each other,
The fourth opening / closing section 15y is open when the opening / closing section 15x is closed, and the fourth opening / closing section 15y is closed when the third opening / closing section 15x is open.

Further, as described above, the first double throw switch 14
And the second double throw switch 15 are linked with each other, so that the first
When the first opening / closing section 14x of the double throw switch 14 is closed, the third opening / closing section 15x of the second double throw switch 15 is closed,
On the other hand, when the second opening / closing section 14y of the first double throw switch 14 is closed, the fourth opening / closing section 15 of the second double throw switch 15 is closed.
y is closed. One input terminal 17a, the first opening / closing portion 14x of the first double throw switch 14, the armature 11, the single pole switch 16, the field coil 12, and the third opening / closing portion 15x of the second double throw switch 15. And the other input terminal 17b are sequentially connected in series.

With the above configuration, during operation, the single pole switch 16 is closed as shown by the solid line, and the first double throw switch 1 is closed.
4, the first opening / closing section 14x is closed as shown by a solid line, and the third opening / closing section 15x of the second double throw switch 15 is closed as shown by a solid line. Therefore, the AC power supply 19 is applied to a series circuit of the armature 11 and the field coil 2, and the armature 11 rotates in a predetermined direction. Next, when the operating state is changed to the dynamic braking state, the single-pole switch 16 is opened as shown by a dotted line, the second opening / closing portion 14y of the first double-throw switch 14 is closed as shown by a dotted line, and the second double-throw switch is opened. The 15 fourth opening / closing portion 15y closes as shown by the dotted line. For this reason, the AC power supply 19 is disconnected from the armature 11 and the field coil 12, and the armature 11 and the field coil 12 form a closed loop. As a result, the armature 11 and the field coil 12 rotating by inertia become a generator, and the electric power generated by the armature 11 is consumed by the resistance component of the field coil 12, so that the armature 11 is braked. Stops soon.

Here, when the contacts of either the double-pole double-throw switch 13 or the single-pole switch 16 are welded, the following occurs. When the movable contact 14a and the first fixed contact 14b forming the first opening / closing portion 14x are welded, the switch can be operated because the first opening / closing portion 14x is originally closed when the switch is set to the operation position. On the other hand, when the switch is set to the braking position, the first opening / closing portion 14x remains closed as described above, but since the third opening / closing portion 15x is opened, the armature 11 and the field coil 12 do not form a closed loop. Therefore, the armature 11 stops without being braked. However, AC power supply 1
Since 9 is separated from the armature 11 and the field coil 12, the armature 11 or the field coil 12 does not burn out.

Movable contact 1 constituting second opening / closing section 14y
If the switch 4a and the second fixed contact 14c are welded, the AC power supply 19 is disconnected from the armature 11 and the field coil 12 when the switch is set to the operation position, so that the armature 11 does not rotate. , Armature 11 and field coil 1
2 does not burn out. On the other hand, when the switch is set to the braking position, the armature 11 and the field coil 12 remain disconnected from the AC power supply 19 because the second opening / closing portion 14y remains closed as described above, and there is no burning.

Movable contact 1 constituting third opening / closing section 15x
When the switch 5a and the first fixed contact 15b are welded to each other, the switch can be operated because the third opening / closing portion 15x is originally closed when the switch is set to the operation position. On the other hand, when the switch is set to the braking position, the third opening / closing portion 15x remains closed as described above, but since the first opening / closing portion 14x is open, the armature 11 and the field coil 12 do not form a closed loop. . Therefore, the armature 11 stops without being braked. However, since the AC power supply 19 is disconnected from the armature 11 and the field coil 12, the armature 11 and the field coil 12
Does not burn out.

Movable contact 1 constituting fourth opening / closing section 15y
5a and the second fixed contact 15c are welded, and when the switch is set to the operation position, the AC power supply 19
Since the armature 11 is separated from the field coil 12, the armature 11 does not rotate, and the armature 11 and the field coil 12 do not burn out. On the other hand, when the switch is set to the braking position, since the fourth opening / closing portion 15y is kept closed as described above, the AC power supply 19 supplies the armature 11 and the field coil 12
And the armature 11 and the field coil 12 are not burned.

When the first opening / closing section 14x and the third opening / closing section 15x are kept closed by welding of the contacts 14a and the like, when the switch is set to the operation position, the operation can be performed because the contacts are originally closed. On the other hand, when the switch is set to the braking position, the braking state is not established.
Since the AC power supply 19 is disconnected from the armature 11 and the field coil 12 because the 6 is opened, the armature 11 and the field coil 12 do not burn out.

When the second opening / closing section 14y and the third opening / closing section 15x are closed by welding of the contacts 14a and the like, the AC power supply 19
Is not applied to the armature 11 and the field coil 12,
The armature 11 does not rotate, and the armature 11 and the field coil 12 do not burn out. On the other hand, when the switch is set to the braking position, the AC power supply 19 is not applied to the armature 11 and the field coil 12 because the fourth opening / closing portion 15y remains closed as described above. The coil 12 does not burn out.

Even when the first opening / closing section 14x and the fourth opening / closing section 15y are closed by welding of the contacts 14a and the like, when the switch is set to the operation position, the AC power supply 19
Is not applied to the armature 11 and the field coil 12,
The armature 11 does not rotate, and the armature 11 and the field coil 12 do not burn out. On the other hand, at the time of braking, since the armature 11 and the field coil 12 do not form a closed loop,
Although the armature 11 is not braked, the AC power supply 19 is not applied to the armature 11 and the field coil 12, so that the armature 11 and the field coil 12 are not burned.

When the second opening / closing portion 14y and the fourth opening / closing portion 15y are closed by welding of the contacts 14a and the like, when the switch is set to the operation position, the armature 11 and the field coil 12 are connected. Since the AC power supply 19 is not applied,
The armature 11 does not rotate, and the armature 11 and the field coil 12 do not burn out. On the other hand, when the switch is set to the braking position, the AC power supply 19 is not applied to the armature 11 and the field coil 12 because the second opening / closing section 14y and the fourth opening / closing section 15y remain closed. Child 11
Also, the field coil 12 does not burn out.

When the contacts of the single-pole switch 16 are welded,
The single-pole switch 16 remains closed and cannot be opened. Therefore, when the switch is set to the operation position, there is no problem because the single-pole switch 16 is originally closed. When the switch is in the braking position, the single-pole switch 16 should be open but remains closed, so that both terminals of the armature 11 are short-circuited by the single-pole switch 16 and the second opening / closing section 14y, and the field The coil 12 is short-circuited by the single-pole switch 16 and the fourth opening / closing section 15y. For this reason, the electric power generated by the armature 11 is not supplied to the field coil 12, so that the armature 11 is not braked. However, since the AC power supply 19 is separated from the armature 11 and the field coil 12, the armature 11 or the field coil 12 does not burn out. Furthermore, even if the welding of the contacts described above and the welding of the contacts of the single-pole switch 16 occur simultaneously, the armature 11 and the field coil 12 do not burn out.

In the above embodiment, the second fixed contact 14c of the first double throw switch 14 is directly connected to the field coil 12, but the present invention is not limited to this. A first braking resistor may be connected to the field coil 12. In this case, the first braking resistor is connected in series with the field winding 12 when the switch is set to the braking position. Further, in the above-described embodiment, the second fixed contact 1 of the single pole switch 16 and the second double throw switch 15 is used.
5c is directly connected, but is not limited thereto, and a second braking resistor may be connected between the second fixed contact 15c and the single-pole switch 16. In this case, the second braking resistor is connected in series with the field winding 12 when the switch is set to the braking position. Note that the first braking resistor and the second braking resistor may both be used, or only one of them may be used. Also,
In the embodiment described above, the armature 11 and the field coil 12 may be interchanged and connected. Also, the above embodiment is
Although it is an example of an AC series-wound commutator motor, the present invention is not limited to this, and may be an example of a DC series-wound motor using a DC power supply instead of an AC power supply. Good.

[0021]

According to the electric motor braking device of the present invention, even when the contacts of the switches included in the electric motor braking device are welded, the power is not directly applied to the armature or the field coil. The armature and the field coil are not burned. For this reason, the reliability of the motor braking device is significantly improved.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of one embodiment of the present invention.

FIG. 2 is a circuit diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Armature 12 Field coil 13 Double pole double throw switch 14 First double throw switch 14x First open / close unit 14y Second open / close unit 15 Second double throw switch 15x Third open / close unit 15y Fourth open / close unit 16 Single pole switch

Claims (1)

(57) [Claims] An electric motor having an armature and a field coil, a first double-throw switch having a first opening / closing section and a second opening / closing section that operate in opposite directions, and a third double-throw switch operating in opposite directions.
A second double-throw switch having an open / close section and a fourth open / close section; and a single-pole switch. During operation, a first open-close section of the first double-throw switch, an armature, a single-pole switch, and a field coil. And the third opening / closing section of the second double throw switch are sequentially connected in series, and, during braking, the second opening / closing section of the first double throw switch, the field coil, and the fourth opening / closing of the second double throw switch. And a first double-throw switch so as to connect the unit and the armature in series,
A motor braking circuit for controlling a second double throw switch and a single pole switch.