JPH0854032A - Braking device for rotating electric machine - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a braking device for a rotating electric machine, the main part of which is an electromagnetic braking device that can be used for a long time. [Structure] An electromagnet wound with a brake coil is provided, and an exciting current is supplied from a power supply device to the brake coil via an exciting circuit to press the brake shoe against a brake ring mounted on a rotor of a rotating electric machine. Equipped with an electromagnetic brake device that stops the rotating electric machine, and when braking of the rotating electric machine is stopped, an exciting current is supplied to the brake coil from the power supply device through an exciting circuit that does not have a resistor from the start speed to the stop of the rotating electric machine. It is characterized in that after the power is supplied and after stopping, an exciting current is supplied from the power supply device through an exciting circuit having a resistor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a braking device for a rotating electric machine, which applies a braking force to the rotating electric machine to stop the rotating electric machine when the operation of the rotating electric machine such as a generator or an electric motor is stopped. The present invention relates to a braking device for a rotating electric machine that enables use of time.

[0002]

2. Description of the Related Art In recent years, for the purpose of simplifying maintenance, water turbine power generation facilities at hydroelectric power stations are
Airless devices have come to be adopted, and braking devices for rotating electric machines such as generators and electric motors are also mainly used as electromagnetic braking devices instead of conventional hydraulic or pneumatic devices. Has come to be used.

FIG. 3 is a conceptual diagram showing an outline of a conventional braking device for a rotary electric machine, the main part of which is an electromagnetic braking device.

In FIG. 3, reference numeral 10 is a rotor of a rotating electric machine to be braked, for example, a rotor of a water turbine generator, 10a is a main shaft of the rotor, and 10b is a brake ring mounted on the bottom surface of the rotor 10 near its peripheral surface. is there. The stator of the turbine generator is omitted, and below the rotor main shaft 10a in the figure,
Although not shown, a water turbine is connected.

Reference numeral 11 is an electromagnetic brake device which is a main part of a braking device for a water turbine generator, and 11a is its brake shoe. A plurality of brake devices 11 are provided at equal intervals along the brake ring 10b.

Although not shown, the electromagnetic brake device 11
Is equipped with an electromagnet wound with a brake coil. When an exciting current is applied to the brake coil and excited, the brake shoe 11a is pushed upward in the drawing and pressed by the brake ring 10b of the rotor 10 to apply a braking force to the rotor 10. It is configured to work. Although only one electromagnetic brake device 11 is shown in FIG. 3, a plurality of electromagnetic brake devices 11 may be provided depending on the capacity of the turbine generator or the size of the rotor.

Reference numeral 12 is a DC power supply device of the electromagnetic brake device 11. The DC power supply device 12 is provided in the vicinity of the rotor main shaft 10a, and a rotation speed detection device 13 that detects the rotation speed of the water turbine generator detects the brake start speed of the water turbine generator, and opens and closes it according to a detection signal. Is connected to the above-mentioned brake coil of the electromagnetic brake device 11 via an excitation circuit 14 having an electric contact 14a that is controlled, and a DC exciting current is supplied to the brake coil by closing the electric contact 14a.

Next, the operation of the conventional braking device for a water turbine generator having the above-mentioned structure, which mainly includes the electromagnetic brake device 11, will be described.

During operation of the turbine generator, the rotation speed (rated rotation speed) of the turbine generator is, of course,
Since it is not necessary to apply a braking force to the rotor 10 which is higher than the brake start speed, the rotation speed detection device 1
3 does not detect the brake start speed,
Since the brake start detection signal is not sent to the electric contact 14a, the electric contact 14a is opened as shown.
Therefore, the electromagnetic brake device 11 is separated from the DC power supply device 12 and is at rest, and its brake shoe 11a is in the state shown in the drawing.

When the water introduced to the water turbine (not shown) is shut off by the operation of stopping the water turbine generator, the rotation speed of the rotor 10 of the water turbine generator gradually decreases, and the braking force is applied in advance in advance. The specified braking start speed is reached. Then, the rotation speed detection device 13 detects this and sends a detection signal to close the electric contact 14a.

When the electrical contact 14a is closed, a normal exciting current is supplied from the DC power supply 12 through the exciting circuit 14 to the brake coil wound around an electromagnet (not shown) of the electromagnetic brake device 11, and the electromagnet is excited. The brake coil is excited to generate a normal magnetic force in the electromagnet.

Therefore, the brake shoe 11a of the electromagnetic brake device 11 is pushed upward by the normal magnetic force generated, and the brake ring 10 of the rotor 10 is pushed up.
The rotor 10 is pressed by b and a normal braking force is applied to the rotor 10. In this way, due to the normal braking action of the electromagnetic brake device 11, the rotation speed of the rotor 10 is further reduced and then stopped.

When the rotor 10 is stopped, the rotation speed detection device 13 detects this and sends a detection signal to open the electric contact 14a, and the exciting current from the DC power supply device 12 which has been energized to the brake coil. Is interrupted, the operation of the electromagnetic brake device 11 is stopped, the state is returned to the illustrated state, and a series of braking control of the turbine generator is completed.

[0014]

By the way, the magnetic force generated by the electromagnetic brake device 11 is obtained by passing an exciting current to the brake coil of the electromagnet equipped in the electromagnetic brake device 11 as described above. However, if it is used for a long time and the normal exciting current continues to flow, the temperature rise of the brake coil will exceed its allowable value, and the insulation of the brake coil will be destroyed or, in the worst case, the brake coil will be blown. There is a fear of doing it.

Therefore, the capacity or the braking time of the electromagnetic brake device 11 is determined by the temperature rise due to the normal exciting current of the brake coil.
It becomes difficult to continuously energize the device for a long time and keep it in the state of use.

For example, in the case of a water turbine generator, if the braking by the electromagnetic brake device 11 is released as described above after the rotor 10 stops rotating due to braking, an external force (water leakage of the water turbine) from the turbine side, which is the prime mover, is released. The torque 10) causes the rotor 10 of the water turbine generator to start rotating again together with the water turbine runner. In this case, the rotor 10 continues to rotate at a low speed, but the oil film of the bearing (not shown) is not formed due to the low speed rotation, so that the bearing is burned.

Therefore, when the turbine generator is to be stopped for a long time, after the rotor 10 is braked and stopped, the electromagnetic brake device 11 is stopped as described above and, for example, a manual portable jack is used. It is necessary to prevent the rotation of the rotor 10.

As described above, since the conventional electromagnetic brake device 11 has various problems in use, it cannot be used for a generator or the like using a water turbine having a large water leakage torque as a prime mover. Met.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a braking device for a rotary electric machine whose main part is an electromagnetic braking device that can be used for a long time.

[0020]

In order to achieve the above object, the present invention provides, in claim 1, a rotation speed detecting device for detecting a rotation speed of a rotating electric machine and a rotor of the rotating electric machine. An electromagnetic type equipped with a brake ring and an electromagnet wound with a brake coil, and when an exciting current is applied to the brake coil, the brake shoe is pressed by the brake ring to exert a braking force on the rotor of the rotating electric machine. A braking device; a first exciting circuit for directly supplying an exciting current from a power source to the brake coil; and a second exciting circuit for supplying an exciting current from the power source to the brake coil via a resistor, When the rotating electric machine is stopped by braking, first, the rotating speed detecting device reduces the rotating speed of the rotating electric machine to a predetermined brake start speed. By detecting, via said first exciting circuit is energized normal excitation current to the brake coil, braking to stop the rotary electric machine by a usual braking force,
Next, it is detected that the rotary electric machine has stopped, and the first excitation circuit is switched to the second excitation circuit, and the brake coil is supplied with the normal excitation current through the second excitation circuit. It is characterized in that a small exciting current is applied to the rotary electric machine so that a braking force smaller than the normal braking force is applied to the rotary electric machine.

According to a second aspect of the present invention, there is provided a rotation speed detecting device for detecting a rotation speed of the rotating electric machine, a brake ring mounted on a rotor of the rotating electric machine, and an electromagnet wound with a brake coil. When an exciting current is applied to the brake coil, the brake shoe presses the brake ring to apply a braking force to the rotor of the rotating electric machine, and an electromagnetic brake device that receives a signal from the rotation speed detecting device to brake the brake. A variable voltage power supply device that supplies an exciting current to the coil, and when stopping the rotating electric machine by braking, first, the rotation speed detecting device lowers the rotation speed of the rotating electric machine to a predetermined brake start speed. It is detected that the power supply device supplies a normal exciting current to the brake coil to operate the rotating electric machine with a normal braking force. The braking is stopped further, and then, it is detected that the rotating electric machine has stopped, and the exciting current smaller than the normal exciting current is supplied to the brake coil by the power supply device, and the normal braking force is applied to the rotating electric machine. It is characterized by controlling so that a smaller braking force is applied.

According to another aspect of the present invention, the rotation speed detecting device for detecting the rotation speed of the rotating electric machine, the brake ring attached to the rotor of the rotating electric machine, and the central shaft to which the base end of the rotating ring is attached have a predetermined time. A switching device provided with a slider that rotates at a predetermined angle with a spacing and a plurality of switching contacts that make sliding contact each time the slider rotates at the predetermined angle, and the plurality of switching contacts, respectively. Equipped with a plurality of electromagnets, one end of each of which is connected via a conductor wire and the other end of which is collectively connected to a power supply device, and a plurality of electromagnets are separately wound. A plurality of electromagnetic brake devices that apply a braking force to the rotor of the rotating electric machine by pressing the brake shoes of the plurality of electromagnets against the brake ring when energized. The power supply device and one of the plurality of switching contacts are connected to each other, and the conductor wire connecting one end of the plurality of brake coils to the plurality of switching contacts is connected to the plurality of brake coils. A second contact that forms a first exciting circuit that simultaneously supplies an exciting current, and the power supply device and the slider are connected to each other so that the exciting current is separately supplied to the plurality of brake coils for a predetermined time. And a switching contact in which the plurality of contacts and one contact are switched and controlled by an output signal of the rotation speed detection device, and the rotating electric machine is stopped by braking. At this time, first, the rotation speed detection device detects that the rotation speed of the rotating electric machine has decreased to a predetermined brake start speed, and the plurality of brakes are passed through the first excitation circuit. An exciting current is simultaneously applied to the coils to stop the rotating electric machine by the plurality of electromagnetic brake devices. Then, it is detected that the rotating electric machine is stopped, and the first exciting circuit outputs the second exciting current to the second exciting circuit. The excitation circuit is switched to the second excitation circuit, and an excitation current is sequentially applied to the plurality of brake coils through the second excitation circuit for a predetermined time, and the rotary electric machine is sequentially scheduled for a predetermined time by a part of the plurality of electromagnetic brake devices. It is characterized by controlling so that a braking force is applied.

[0023]

According to the first aspect, when the rotating electric machine is stopped by braking,
The rotation speed detection device detects that the rotation speed of the rotating electric machine has decreased to the brake start speed, and a normal exciting current is supplied to the brake coil through the first exciting circuit so that the rotating electric machine receives the normal braking force. The braking is stopped by, and then the stop of the rotating electric machine is detected, and the first exciting circuit is switched to the second exciting circuit having a resistor, and the brake coil is connected to the above-mentioned brake coil via the second exciting circuit. Since an exciting current smaller than the normal exciting current is applied to apply a braking force smaller than the normal braking force described above, it can be used for a long time.

In the second aspect, the variable voltage power supply device receives the detection signal of the rotation speed detection device, and the respective currents corresponding to the braking time and the stop holding time are directly supplied to the braking device. Therefore, the device is simple. It can be used for a long time even though it is configured as.

Further, according to the present invention, the rotation speed detecting device detects that the rotation speed of the rotating electric machine has decreased to the brake start speed, and the plurality of all electromagnetic brake devices rotate through the first exciting circuit. Brake the machine, then
Detecting that the rotating electric machine has stopped, the first exciting circuit is switched to the second exciting circuit having a switch, and a plurality of electromagnetic brake devices are sequentially operated at predetermined time intervals via the second exciting circuit. Since the switching force is changed so that the braking force is always applied by one electromagnetic brake device, it can be used for a long time.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.
Prior to the description of the present invention, first, the principle of the present invention will be described.

The object of the present invention is to make the electromagnetic brake device usable for a long time as described above.

Normally, the force required to restart the once stopped rotor is much larger than the force required to brake the rotating rotor. Therefore, the braking force required to keep the rotor of the rotating electric machine stopped is about 1/10 of the braking force required for normal braking.

The strength of the magnetic force (braking force) of the electromagnetic brake device is proportional to the magnitude of the exciting current supplied to the brake coil. Therefore, in order to reduce the braking force of the rotating electric machine to 1/10, the magnitude of the exciting current supplied to the brake coil should be 1/100 of the exciting current during normal braking.
Just set it to 10. If the exciting current is reduced to 1/10, the temperature rise of the brake coil is also suppressed, and during normal braking, the electromagnetic brake device that was rated for a short time is used as a continuously rated electromagnetic brake device. It becomes possible to use it for a long time.

Further, in a large rotating electric machine provided with a plurality of electromagnetic brake devices, it is not necessary to apply braking force to the rotor using all the electromagnetic brake devices during stop, and one rotor Is sufficient.

Therefore, from the braking start speed of the rotating electric machine to the stop, normal electromagnetic braking is performed by using all the electromagnetic braking devices, and after stopping, it is used from among a plurality of electromagnetic braking devices. The electromagnetic brake devices to be used may be sequentially switched so that one device is always used for an appropriate time. In this case, the rest time is much longer than the use time of the electromagnetic brake device, and the brake coil whose temperature has risen due to use is sufficiently cooled during the rest time. As a result, similar to the above case, during normal braking, the electromagnetic brake device that was rated for a short time can be used as an electromagnetic brake device with a substantially continuous rating. Time can be used.

Next, a braking device for a rotating electric machine according to the present invention based on the above principle will be described.

FIG. 1 shows an embodiment of the present invention and is a conceptual diagram of a braking device for a rotary electric machine having an electromagnetic brake device as a main part. The same parts in FIG. 3 are designated by the same reference numerals. Therefore, detailed description thereof will be omitted.

In FIG. 1, 10 is a rotating electric machine to be braked, for example, a rotor of a water turbine generator, 10a is a rotor main shaft, 10b.
Is a brake ring, 11 is an electromagnetic brake device, 11a
Is a boot brake, 12 is a DC power supply device, and 13 is a rotation speed detection device.

The difference between FIG. 1 and FIG. 3 lies in the excitation circuit 14 in FIG. 3, and in FIG.
And 16 and the electric contact 14a in FIG.
1 is changed to the switching contact 17 and, although not shown, only the output signal of the rotation speed detecting device 13 associated with the switching operation of the switching contact 17 is changed, which will be described in detail below.

That is, in FIG. 1, reference numeral 15 is a first exciting circuit, which is equivalent to the exciting circuit 14 in FIG. Reference numeral 16 is a second exciting circuit, and a resistor 16a is inserted in the circuit.

Reference numeral 17 denotes a switching contact whose switching operation is controlled by the rotation speed detecting device 13. The rotation contact speed of the hydraulic turbine generator is N, and the predetermined braking start speed of the hydraulic turbine generator is N.
b, the switching conditions of the switching contact 17 in FIG. 1 are as follows.

N> Nb Position shown N <Nb Closing lower contact shown When stopping Stopping upper contact shown In the following, the operation of the device of the present invention having the above-mentioned configuration will be described.

When the water introduced to the water turbine (not shown) is shut off by the operation of stopping the operation of the water turbine generator, the rotation speed of the rotor 10 gradually decreases, and a predetermined braking for applying the braking force is eventually obtained. Reach the starting speed. Then, the rotation speed detection device 13 detects this and sends a detection signal to operate the switching contact 17 downward in the drawing to close the lower contact.

When the lower contact of the switching contact 17 is closed,
The brake coil wound around an electromagnet (not shown) of the electromagnetic brake device 11 is supplied with a normal excitation current from the DC power supply device 12 via the first excitation circuit 15 to excite the brake coil of the electromagnet to generate the electromagnet. To generate a magnetic force.

Therefore, the brake shoe 11a of the electromagnetic brake device 11 is pushed upward in the drawing by the generated magnetic force and is pressed by the brake ring 10b of the rotor 10 to apply a normal braking force to the rotor 10.

At this time, the magnitude of the exciting current applied to the brake coil of the electromagnetic brake device 11 depends on the flywheel effect of the rotor 10 of the water turbine generator, the stirring loss of the lubricating oil of the bearing (not shown), and the electromagnetic brake device 11. Depending on the capacity and number of.

The following is an example of an electromagnetic brake device applied to a turbine generator. Total number of turns of brake coil: 1656 turns Resistance value of brake coil: 4.85 ohm Power supply voltage: DC 100V Excitation current of brake coil: 20.6A Brake shoe pushing force: 600Kg Electromagnetic method shown as an example above The braking action of the brake device 11 further reduces the rotational speed of the rotor 10, and the rotor 10 eventually stops braking.

When the rotor 10 stops, the rotation speed detecting device 13 detects this and sends a detection signal to switch the switching contact 17 to the upper side in the drawing, to open the lower contact and close the upper contact. As a result, the exciting current of the brake coil of the electromagnetic brake device 11 is supplied from the DC power supply device 12 to the resistor 1
It will be energized via the second excitation circuit 16 having 6a. In this case, the resistance value of the resistor 16a is obtained by dividing the magnitude of the exciting current of the brake coil by 1/1 of the normal value.
The value is selected to be reduced to about 0. That is, the voltage applied to the brake coil after the turbine generator is stopped is 10V because the power supply voltage during normal braking is 100V.

In this way, the magnitude of the exciting current of the brake coil is reduced and the temperature rise of the brake coil is suppressed, so that the electromagnetic brake device 11 is substantially continuous after the water turbine generator is stopped. It can be used as a rated device and can be used continuously for a long time.

In the above embodiment, the current supplied to the brake coil is changed by switching the circuits 15 and 16, but the DC power supply device 12 is a variable voltage power supply device using a thyristor or the like, and the signal of the rotation speed detection device 13 is The variable power supply device may be put in to directly supply the respective currents to the brake device 11 depending on the time of braking and the time of holding the stop.

Further, according to the above-mentioned principle, the braking force required to keep the rotor of the rotating electric machine stopped is about 1/10 of the braking force during normal braking. Therefore, in a large rotating electric machine including a plurality of electromagnetic brake devices, it is not necessary to apply a braking force to the rotor by using all the electromagnetic brake devices during stop.
It is enough to use a stand.

Therefore, from the braking start speed of the rotating electric machine to the stop, normal electromagnetic braking is performed by using all electromagnetic braking devices, and after stopping, it is used from among a plurality of electromagnetic braking devices. The electromagnetic brake devices to be used may be sequentially switched so that one device is always used for an appropriate time. In this case, the rest time is much longer than the use time of the electromagnetic brake device, and the brake coil whose temperature has risen due to use is sufficiently cooled during the rest time. As a result, similar to the above case, during normal braking, the electromagnetic brake device that was rated for a short time can be used as an electromagnetic brake device with a substantially continuous rating. Time can be used.

FIG. 2 is a connection diagram showing a main part of another embodiment of the present invention, and the same parts in FIG. 1 are designated by the same reference numerals. In addition, the braked rotary electric machine according to the present embodiment includes 6
The case where two electromagnetic brake devices 11 having the same specifications are provided is shown.

In FIG. 2, 11c1 to 11c6 are
Each of the above six electromagnetic brake devices 1 with the same specifications
It is the brake coil of the electromagnet equipped in 1. Reference numeral 12 is a DC power supply device, and 13 is a rotation speed detection device for detecting the rotation speed of the rotating electric machine.

Reference numeral 18 is a switch. The switch 18 is provided with an oscillator 18a that outputs a drive signal each time a predetermined time elapses when a control power supply is connected. A step motor 18b is provided which rotates 60 degrees each time a drive signal is received, for example, clockwise rotation. The slider 1 is attached to the rotary shaft 18c of the step motor 18b.
Since the base end of 8d is attached, and the six switching contacts 18e are arranged at positions equidistant from each other about the rotation shaft 18c, the central angle between them is 60 degrees. Each time the slider 18d is rotated, the tip of the contactor 18e is sequentially switched in the clockwise direction and slidably contacts the head of the contactor 18e.

One end of each of the brake coils 11c1 to 11c6 is connected to each of the six switching contacts 18e, and the other ends of the brake coils 11c1 to 11c6 are collectively connected to the N (negative) pole of the DC power supply device 12. Connected to.

A switching contact 19 is switched and controlled by a detection signal sent from the rotation speed detecting device 13. The first contact 19a of the switching contact 19 is the DC power supply 12
Connected between the P (positive) pole of the switch 18 and the first switching contact 18e1 of the switching device 18, and the five contacts of the second contact 19b to the sixth contact 19f are respectively the six brake coils 11c.
One end of each of 1 to 11c6 is connected between six conductors connecting the switching contact 18e to the conductor. When the first contact point 19a to the sixth contact point 19f are closed, the direct current power supply device 12 releases the six brake coils 1
A first excitation circuit that simultaneously supplies an excitation current to 1c1 to 11c6 is configured.

The seventh contact 19g of the switching contact 19 is
It is connected between a control power supply (not shown) and the transmitter 18a,
Further, the eighth contact 19h is connected to the P of the DC power supply device 12.
It is connected between the (positive) pole and the slider 18b of the switch 18. Then, the seventh contact point 19g and the eighth contact point 19h
Is closed (at this time, the first contact 19a to the sixth contact 19f are opened), the slider 18d of the switching device 18 is rotated stepwise at a predetermined time interval by the operation of the step motor 18b. A second exciting circuit that sequentially applies an exciting current to the six brake coils 11c1 to 11c6 from the DC power supply device 12 for a predetermined scheduled time is formed by slidingly contacting the head of the switching contact 18e.

Next, the operation of another embodiment of the present invention having the above structure will be described with reference to FIG.

Since the speed during operation of the water turbine generator is the rated speed, the rotation speed detecting device 13 does not operate and the switching contact 1
Each of the contacts 9 is open and in the illustrated state. Therefore, the switch 18 does not operate, and the slider 18d is stopped at the position shown in the figure, for example. When the rotational speed of the rotor 10 gradually decreases and reaches a predetermined braking start speed by the operation stop operation of the water turbine generator, the rotational speed detection device 13 detects this and sends a detection signal to the switching contact. 19 is operated to the left side in the drawing, and its first contact point 19a to sixth contact point 19
Close f.

As a result, each electromagnetic brake device 11
An exciting current is supplied to the brake coils 11c1 to 11c6 from the DC power supply device 12 via the first exciting circuit, and magnetic force is generated in each electromagnet. Therefore, each brake shoe 11a of each electromagnetic brake device 11 is
Is pushed upward in the drawing by the generated magnetic force and is pressed by the brake ring 10b of the rotor 10 to exert a braking force on the rotor 10, and the braking action further reduces the rotational speed of the rotor 10, The child 10 will eventually stop braking.

When the rotor 10 is stopped, the rotation speed detecting device 13 detects this and sends a detection signal to switch the switching contact 19 to the right in the drawing, and the first contact 19a to the sixth contact 19a.
The contact 19f is opened, and at the same time, the seventh contact 19g and the eighth contact 19h are closed. As a result, each brake coil 11c1 to 1c of each electromagnetic brake device 11 is
The exciting current of 1c6 is cut off, and each electromagnetic brake device 11 enters a pause.

However, immediately after that, the brake coil 11c
1, due to the closing of the eighth contact 19h of the switching contact 19,
From DC power supply 12 to 8th contact point 19h, slider 18d
An exciting current is supplied through the (second exciting circuit), and the rotor 10 is braked only by the electromagnetic brake device 11 including the brake coil 11c1.

Further, by closing the seventh contact 19g of the switching contact 19, the transmitter 18a starts its operation because it is connected to a control power source (not shown), and sends a drive signal to the step motor 18b at a predetermined time interval. . Since the step motor 18b rotates clockwise by 60 degrees each time the drive signal is received, the slider 18d whose base end is attached to the rotation shaft 18c also rotates clockwise by 60 degrees.
The tip of the tip comes into sliding contact with the head of the switching contact 18e while being sequentially switched clockwise.

Therefore, the exciting current supplied to the brake coil from the DC power supply device 12 via the eighth contact point 19h and the slider 18d (second exciting circuit) is 11c2 from the brake coil 11c1 every predetermined time. , 11c3 ……
Since it is sequentially switched to, the electromagnetic brake device 11 is similarly switched.

Therefore, after the braking is stopped, the rotor 10 is sequentially braked by using only one electromagnetic brake device which is switched every time a predetermined time elapses, and the other five electromagnetic brakes are braked. The device is placed in a dormant state. As described above, the braking force of the rotor 10 required during the stop is sufficient by using one electromagnetic brake device, and the temperature is increased by the use during the rest period. The brake coil is cooled sufficiently.

As a result, each electromagnetic brake device 11
Is a short-time rating, but six electromagnetic brake devices 11
With the above switching and use, when viewed as one electromagnetic brake device as a whole, it becomes substantially equivalent to a continuous rating and can be used for a long time.

In the above embodiment, one electromagnetic brake device is always used, but two or three electromagnetic brake devices are always used depending on the conditions such as the braking force and the rating of the brake coil.
It is also possible to use a part of the electromagnetic brake device such as a table.

In each of the above embodiments, the electromagnetic brake device 11 uses a direct current excitation system, but the electromagnetic brake device is not necessarily a direct current excitation system but an alternating current excitation system. In such a case, the DC power supply device 12 is an AC power supply device because it may be of a system. Further, although the switching contacts 17, 19 and the switching device 18 also use mechanical devices, it is more preferable to use non-contact type devices such as thyristors instead of mechanical devices.

[0066]

As described above, the present invention has been described in detail. According to the present invention, when the rotary electric machine is braked and stopped by using the electromagnetic brake device having the electromagnet around which the brake coil is wound, A large normal exciting current is applied to the brake coil from the brake start speed to a stop where the rotating force is relatively large, and the rotating electric machine is stopped by a large normal braking force. The time for energizing is a relatively short time from the start of braking to the stop, and the purpose of use can be sufficiently achieved by an inexpensive electromagnetic brake device with a short-time rating.

After the rotating electric machine is stopped, a small exciting current is supplied to the brake coil by controlling the resistor or the power supply device to apply a small braking force. An inexpensive electromagnetic brake device with a time rating can be used as an electromagnetic brake device with a substantially continuous rating, so that it can be used for a long time.

Further, all the electromagnetic brake devices are used only for a relatively short time from the start of braking to the stop, and after the stop, the electromagnetic brake devices are sequentially switched at predetermined time intervals so that a part of the electromagnetic brake devices is always operated. Since the electromagnetic brake device is used and the rest is stopped, the brake coil whose temperature has risen during use is sufficiently cooled during the stop and can be used for a long time.

Further, according to the present invention, for example, even for a rotating electric machine in which an expensive hydraulic brake device has been modified into an electromagnetic brake device, the exciting circuit can be simply modified without modifying the electromagnetic brake device main body. Thus, the electromagnetic brake device can be easily used for a long time.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a braking device for a rotating electric machine, which has an electromagnetic brake device as a main part, according to an embodiment of the present invention.

FIG. 2 is a connection diagram showing a main part of another embodiment of the present invention.

FIG. 3 is a conceptual diagram showing a conventional braking device for a rotary electric machine whose main part is an electromagnetic braking device.

[Explanation of symbols]

 10 Rotor of Rotating Electric Machine 10a Rotor Spindle 10b Brake Ring 11 Electromagnetic Brake Device 11a Brake Shoe 11c1 to 11c6 Brake Coil 12 DC Power Supply Device 13 Rotation Speed Detection Device 15 First Excitation Circuit 16 Second Excitation Circuit 16a Resistor 17 Switching Contact 18 Switching Device 18a Transmitter 18b Step Motor 18c Rotating Shaft of Step Motor 18d Slider 18e Switching Contact 19 Switching Contact

Claims (3)

[Claims] 1. A rotation speed detecting device for detecting a rotation speed of a rotating electric machine, a brake ring mounted on a rotor of the rotating electric machine, and an electromagnet wound with a brake coil, the exciting current being supplied to the brake coil. When the current is energized, the brake shoe presses the brake ring to apply a braking force to the rotor of the rotating electric machine, and the first excitation for directly applying an excitation current from the power supply device to the brake coil. A second exciting circuit for supplying an exciting current from the power supply device to the brake coil via a resistor, and when stopping the rotating electric machine by braking, first by the rotation speed detecting device, The brake coil is detected via the first excitation circuit by detecting that the rotation speed of the rotating electric machine has decreased to a predetermined brake start speed. To the second exciting circuit by detecting that the rotating electric machine has stopped by applying a normal exciting current to the rotating electric machine to stop the rotating electric machine by a normal braking force. Switching to the brake coil, and applying an exciting current smaller than the normal exciting current to the brake coil through the second exciting circuit to control the rotating electric machine to apply a braking force smaller than the normal braking force. A braking device for a rotating electric machine, characterized by: 2. A rotation speed detecting device for detecting a rotation speed of a rotating electric machine, a brake ring mounted on a rotor of the rotating electric machine, and an electromagnet wound with a brake coil, the exciting current being supplied to the brake coil. Is energized, the brake shoe presses the brake ring to apply a braking force to the rotor of the rotating electric machine, and an exciting current to the brake coil upon receiving a signal from the rotation speed detection device. When the rotating electric machine is stopped by braking, the rotating speed detecting device first detects that the rotating speed of the rotating electric machine has dropped to a predetermined brake start speed. Then, a normal excitation current is supplied to the brake coil by the power supply device, and the rotating electric machine is stopped by a normal braking force. Next, detecting that the rotating electric machine has stopped, energizing the brake coil with an exciting current smaller than the normal exciting current by the power supply device,
A braking device for a rotating electric machine, which is controlled so that a braking force smaller than the normal braking force is applied to the rotating electric machine. 3. A rotation speed detecting device for detecting a rotation speed of a rotating electric machine, a brake ring attached to a rotor of the rotating electric machine, and a rotating shaft to which a base end of the rotating ring is attached, with a predetermined time interval and a predetermined angle. A switching device including a rotating slider and a plurality of switching contacts that make sliding contact each time the slider rotates by the predetermined angle; and a plurality of switching contacts each having a wire at one end thereof. Is equipped with a plurality of electromagnets, each of which is separately wound with a plurality of brake coils that are connected to each other and are collectively connected to the power supply device, and when an exciting current is applied to the plurality of brake coils, A plurality of electromagnetic brake devices that apply a braking force to the rotor of the rotating electric machine by pressing the brake shoes of the plurality of electromagnets against the brake ring, the power supply device, and the plurality of electromagnetic brake devices. Of one of the switching contacts and between the conductors connecting one end of the plurality of brake coils to the plurality of switching contacts, and an exciting current is simultaneously applied to the plurality of brake coils. A plurality of contacts forming the first exciting circuit and a second exciting circuit for connecting the power supply device and the slider to each other to separately energize the plurality of brake coils with an exciting current for a predetermined time. And a switching contact in which the plurality of contacts and one contact are switched and controlled by an output signal of the rotation speed detection device, the rotation speed when stopping the rotating electric machine by braking. With the detection device,
It is detected that the rotation speed of the rotating electric machine has decreased to a predetermined brake start speed, and an exciting current is simultaneously supplied to the plurality of brake coils via the first exciting circuit, so that the rotating electric machine is connected to the plurality of brake coils. Braking is stopped by an electromagnetic brake device, then, it is detected that the rotating electric machine is stopped, the first exciting circuit is switched to the second exciting circuit, and the second exciting circuit is used to switch to the second exciting circuit. A rotating electric machine characterized in that an exciting current is sequentially applied to a plurality of brake coils for a predetermined time and a braking force is sequentially applied to the rotating electric machine by a part of the plurality of electromagnetic brake devices. Braking system.