JP2001341987A - Lifting device and regenerative power processing method for lifting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lifting device, preventing the destruction of electronic parts constituting a power circuit for supplying power to a lifting motor by effectively processing regenerative power generated when the lifting motor is rotated to the direction of lift-down and more properly maintaining a lift- down speed than usual, and to provide a regenerative power processing method for the device. SOLUTION: This lifting device comprises a regenerative voltage detecting means connecting to a motor driving circuit 4 for driving the lifting motor 2 a regenerative resistance circuit part 8 having a regenerative resistance and a switching element for conducting a regenerative current in the regenerative resistance, for detecting a regenerative voltage generated in the lifting motor 2, and a regenerative resistance control part 10 for turning on/off the switching element in the regenerative resistance circuit part 8 when a value for the regenerative current exceeds an preset value. The regenerative power is consumed by conducting in the regenerative resistance the regenerative current generated in the lifting motor 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lifting device, and more particularly to a lifting device used for lifting and moving a cared person such as an elderly person, a physically handicapped person, a patient, and the like, and a regenerative electric power process of the lifting device. It is about the method.

[0002]

2. Description of the Related Art In general, when a cared person such as an elderly person, a physically handicapped person, or a patient is laid on a bed or bathed, the cared person may need to be lifted and moved. As described above, in order to elevate and lower the cared person, for example, an elevating device as shown in FIG. 8 is conventionally used (see Japanese Utility Model Laid-Open No. 6-44376).

In this elevating device, an apparatus main body 50 is provided so as to be able to travel along a rail 54 provided on a gantry 52, and an elevating motor,
A winding drum driven by the lifting motor,
An electromagnetic brake mechanism for restraining the rotation of the lifting motor and a control circuit (not shown) for controlling these mechanisms are provided. The base end of the wire 56 is fixed to the winding drum. The middle part is wound. The distal end of the wire 56 is connected to the device main body 50.
Is pulled out to the outside, and a hanger part 60 is attached to the end of the hanger part 60 via a hanging bracket 58.
The suspension belt 62 is hung. Further, a power cord 64 arranged along the gantry 52 and the rail 54 is connected to the apparatus main body 50, and an operation switch 68 is connected via a control cable 66.

When an ascending signal or a descending signal is input by operating the operation switch 68, the restraint of the elevating motor by the brake mechanism is electromagnetically released in response to the signal, and the elevating / lowering mechanism in the apparatus main body 50 is released. The wire 56 is wound up or down by the winding drum by the forward or reverse rotation of the motor for the
Moves up and down, and the care receiver is raised and lowered.

Further, the lifting device is provided with a manual lowering operation cord 70 in order to cope with a state in which the care receiver is lifted upward and a power failure or the like occurs. Is pulled down, the restraint of the elevating motor by the brake mechanism in the apparatus main body 50 is mechanically released, and the care receiver can descend by its own weight.
If it is uneasy to accelerate when descending, the lifting motor is braked and stopped when the hand is released from the descending operation cord 70.

[0006]

However, the above-mentioned prior art has the following problems. (1) When the elevating motor of the apparatus main body 50 is rotated in the descending direction by the operation switch 68 and the weight of the cared person is heavy and an excessive load is applied to the elevating motor, the elevating motor slides. Becomes negative, and this motor acts as an induction generator, and as a result, regenerative electric power is generated. In the conventional device shown in FIG. 8, since no measures are taken to effectively treat the regenerative power generated in such a case, a power supply circuit for supplying power to the motor for raising and lowering the regenerative power is configured. There is a risk of flowing to the electronic component side and destroying the electronic components constituting the circuit.

(2) In a normal case, even when the power of the elevating motor is turned on, the elevating motor is restrained by the brake mechanism unless an up signal or a down signal is input from the operation switch 68. When the brake mechanism fails or the brake is manually released, the elevating motor rotates in the descending direction due to the weight of the cared person. Even when such a lifting motor is unexpectedly rotated in the downward direction, regenerative power is generated and electronic components constituting a power supply circuit for supplying power to the lifting motor are destroyed in the same manner as in (1) above. It is assumed that

(3) Further, in the conventional apparatus shown in FIG. 8, when the elevating motor does not operate due to a power failure or the like,
The lifting operation string 70 is pulled to release the restraint of the lifting / lowering motor by the brake mechanism. At this time, the lifting / lowering motor rotates in the downward direction at a speed corresponding to the weight of the cared person. Also at this time, a regenerative electric power corresponding to the descending speed is generated in the elevating motor, and the regenerative electric power is used by the control circuit for controlling the elevating motor in the same manner as in the above (1) and (2). Electronic components may be damaged. Also, when the restraint of the brake mechanism is released by manual operation, the cared person descends at a speed corresponding to the weight of the weight (the size of its own weight), so it is difficult to adjust the descending speed to an appropriate value. In particular, a care receiver having a heavier weight descends at a higher speed, so that care must be taken in the operation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to solve the problems pointed out in the above (1) to (3), that is, to raise and lower the motor in the descending direction. A lifting device capable of effectively processing regenerative electric power generated when rotated to prevent the destruction of electronic components constituting a power supply circuit for supplying power to the lifting motor, and maintaining a lowering speed more appropriately than before, and a lifting device therefor. An object of the present invention is to provide a regenerative power processing method for a device.

[0010]

According to a first aspect of the present invention, there is provided an elevating device, comprising: a regenerative resistor and a regenerative resistor for a motor drive circuit for driving an elevating motor up and down; While connecting a regenerative resistor circuit portion having a switching element for supplying a regenerative current to the resistor, a regenerative voltage detecting means for detecting a regenerative voltage generated in the elevating motor, and a value of the regenerative voltage being a predetermined value set in advance A regenerative resistance control section for turning on / off the switching element of the regenerative resistance circuit section when the power exceeds the regenerative resistance circuit section, wherein a regenerative current generated by the elevating motor flows through the regenerative resistance to consume regenerative power. Features.

According to a fourth aspect of the present invention, there is provided a regenerative power processing method for a lifting device, wherein a regenerative voltage generated by a motor for lifting and lowering is monitored, and when a value of the regenerative voltage exceeds a predetermined value set in advance. A switching element connected to a motor drive circuit for driving the lifting motor and having a regenerative resistor and a switching element for supplying a regenerative current to the regenerative resistor; The regenerative power is consumed by supplying power to the power supply.

Thus, when the lifting / lowering motor is rotated in the downward direction, the slip becomes negative due to the overload applied to the lifting / lowering motor and regenerative power is generated, and the value of the regenerative voltage is set in advance. When the value exceeds a predetermined value, the switching element of the regenerative resistor circuit is turned on / off and regenerative power is consumed by the regenerative resistor, so that the electronic components constituting the power supply circuit for supplying power to the elevating motor are regenerated. It is prevented from being destroyed by electric power. In addition, it is possible to control the down speed to be appropriate by changing the duty ratio of energization by turning on / off the switching element.

According to a second aspect of the present invention, in addition to the configuration of the first aspect of the invention, a brake for restraining the elevation motor is provided, and a power supply for supplying power to the elevation motor is turned on. And a restraint rotation detecting means for detecting that the lift motor has rotated in the descending direction in a state in which a release signal for releasing the restrained state of the lift motor by the brake is not input; Short-circuit generating means for switching the connection of the motor drive circuit to perform power generation braking so that both ends of the elevating motor are short-circuited when the state is detected.

[0014] With this configuration, when the power of the elevating motor is turned on, the elevating motor is rotated in a state in which the elevating motor is unexpectedly rotated in the descending direction when the brake mechanism fails or the brake is manually released. Since the power generation braking is performed by short-circuiting, it is possible to prevent the electronic components constituting the power supply circuit that supplies power to the elevating motor from being destroyed by the regenerative power, and to control the descent speed to be appropriate.

According to a third aspect of the present invention, in addition to the configuration of the first aspect of the invention,
In a state where a power supply for supplying electric power to the elevating motor is turned off, a means for supplying a regenerative current to the regenerative resistor when the elevating motor is rotated in a downward direction is provided.

As a result, when the lifting / lowering motor is not operated due to a power failure or the like and the brake mechanism of the lifting / lowering motor is released, when the lifting / lowering motor is rotated in the downward direction to generate regenerative power, the regenerative current is reduced. Is forced to flow through the regenerative resistor, so that the descending speed can be adjusted to an appropriate value depending on the value of the regenerative resistor. Further, it is possible to prevent the electronic components constituting the power supply circuit for supplying power to the lifting / lowering motor from being damaged by the regenerative power due to the overvoltage due to the regenerative voltage.

[0017]

FIG. 1 is a block diagram showing a main configuration of an electric control system of a lifting device according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes the entire elevating device, 2 denotes an elevating motor (here, a DC motor), 4 denotes a motor drive circuit for driving the elevating motor 2,
Reference numeral 6 denotes a motor control unit that controls the elevating motor 2 via the motor drive circuit 4.

Reference numeral 8 denotes a regenerative resistor circuit for processing regenerative electric power generated by the elevating motor 2, and reference numeral 10 denotes a regenerative resistor controller for controlling the regenerative resistor circuit 8. The details of the motor drive circuit 4 and the regenerative resistor circuit section 8 will be described later. Reference numeral 12 denotes a rotary encoder for detecting the amount of hoisting and unwinding of the wire due to raising / lowering rotation of the lifting / lowering motor 2. Reference numeral 14 denotes a motor power supply circuit, which supplies electric power to the lifting / lowering motor 2 via the motor driving circuit 4. 16 is a power supply voltage detection circuit, which is a motor power supply circuit 1
4 is detected.

Reference numeral 18 denotes an operation unit.
4 for inputting a command signal for turning on / off the power supply from the power supply 4 and rotating the up / down motor 2 up / down. Reference numeral 20 denotes a controller, which controls the motor controller 6 and the regenerative resistor controller 10 based on an input command from the operation unit 18 and detection outputs of the power supply voltage detection circuit 16 and the rotary encoder 12, and includes a CPU and the like. Is done.
A control unit power supply circuit 22 supplies power to the controller unit 20, the motor control unit 6, the regenerative resistance control unit 10, and the like.

The rotary encoder 12 and the controller unit 20 are defined as constrained rotation detecting means, the power supply voltage detecting circuit 16 is defined as regenerative voltage detecting means, and the controller unit 20 is defined as claimed. It corresponds to the short circuit generating means of the range and the means for forcibly flowing the regenerative current to the regenerative resistor.

FIG. 2 is a circuit diagram showing details of the motor drive circuit 4 and the regenerative resistor circuit section 8.

The motor drive circuit 4 includes four switching elements Q1 to Q4 such as FETs connected in a bridge type with the lifting motor 2 arranged at the center, and each switching element Q
It comprises bypass diodes D1 to D4 individually connected in parallel to Q1 to Q4, and a normally-off type power supply relay contact RY1. Then, each of the switching elements Q1 to Q4 and the power supply relay contact RY1 is turned on / off.
The off operation is controlled by the motor control unit 6 based on a command from the controller unit 20. Note that B
1 and B2 are connection terminals for connection to the motor power supply circuit 14.

On the other hand, the regenerative resistor circuit section 8 includes a regenerative resistor R,
The switching element Q5 is configured to include one switching element Q5 connected in series for supplying a regenerative current to the regenerative resistor R, and a normally-on interlocking relay contact RY2 connected in parallel to the switching element Q5. The power supply to the regenerative resistor R by the on / off operation of the switching element Q5 is controlled by the regenerative resistor controller 10 based on a command from the controller 20.

Further, the power supply relay contact RY1 and the interlocking relay contact RY2 operate complementarily to each other, that is, when one power supply relay contact RY1 is turned on, the other interlocking relay contact RY2 is turned off, and When the power supply relay contact RY1 is turned off, the other interlocking relay contact RY2 is turned on.

Next, the operation and operation of the lifting device 1 having the above-described configuration will be described. (1) When the power to the lifting motor 2 is turned off (see Fig. 2)

In this case, as shown in FIG. 2, the power supply relay contact RY1 of the motor drive circuit 4 is off, and the interlocking relay contact RY2 of the regenerative resistor circuit 8 is on. Further, since all the switching elements Q1 to Q4 of the motor drive circuit 4 are off, the elevating motor 2 stops operating. At this time,
The switching element Q5 of the regenerative resistor circuit section 8 is off.

(2) When the lifting motor 2 is rotated in the ascending direction (see FIG. 3) When a power-on signal is input by the operation unit 18, the motor control unit 6 is controlled by a command from the controller unit 20.
Turns on the power supply relay contact RY1 of the motor drive circuit 4. For this reason, the interlocking relay contact R of the regenerative resistor circuit section 8
Y2 turns off.

Subsequently, when an ascending signal of the elevating motor 2 is inputted from the operation unit 18 to rotate the elevating motor 2 in the ascending direction, as shown in FIG. In response to a command from the section 20, the motor control section 6 switches one of the switching elements Q2 and Q3 at both ends of the elevating motor 2 with a predetermined duty ratio, and switches the other switching element Q3. Is turned on, and the remaining switching elements Q1 and Q4 are both turned off.

As a result, a current flows along the path indicated by the broken line arrow in FIG. 3 and the elevating motor 2 is rotated in the ascending direction at a predetermined speed. At this time, the switching element Q5 of the regenerative resistor circuit section 8 is off.

(3) When the lifting motor 2 is normally rotated in the downward direction (see FIG. 4). When a power-on signal is input by the operation unit 18, the motor control unit 6 receives a command from the controller unit 20.
Turns on the power supply relay contact RY1 of the motor drive circuit 4. For this reason, the interlocking relay contact R of the regenerative resistor circuit section 8
Y2 turns off.

Subsequently, when a signal for lowering the motor 2 is input from the operation unit 18 in order to rotate the motor 2 in the lowering direction, a command from the controller 20 corresponding to this signal is given by As shown in FIG. 4, the motor control unit 6 switches one of the switching elements Q1 and Q4 at both ends of the elevating motor 2 with a predetermined duty ratio, and switches the other switching element Q4. Is turned on, and the remaining switching elements Q2 and Q3 are both turned off.

As a result, a current flows along a path indicated by a dashed arrow in FIG. That is, since the electric current flows through the motor 2 in the direction opposite to that in FIG. 3, the motor 2 is rotated at a predetermined speed in the downward direction. At this time, the switching element Q5 of the regenerative resistor circuit section 8 is off.

(4) When the lifting / lowering motor 2 is rotated in the downward direction under an overloaded condition (see FIG. 5). In this case, the power supply relay contact RY1 of the motor drive circuit 4 is turned on. , The interlocking relay contact RY2 is off. In addition, the lifting motor 2
Is input, the motor control unit 6
As shown in FIG. 5, the motor 2
Are turned on, and the other switching elements Q2 and Q3 are both turned off. This is similar to the case shown in FIG.

At this time, when the weight of the cared person is heavy and an excessive load is applied to the elevating motor 2, the slip of the elevating motor 2 becomes negative and regenerative electric power is generated.

This regenerative power is applied to the motor power supply circuit 14 via the motor drive circuit 4. The power supply voltage detection circuit 16 monitors the regenerative voltage based on the regenerative power. When the regenerative voltage exceeds a predetermined value, a signal to that effect is given to the controller unit 20. In response to a command from the controller unit 20 in response to this, the regenerative resistor control unit 10 turns on / off the switching element Q5 of the regenerative resistor circuit unit 8 with a predetermined duty ratio.
Turn off.

As a result, the regenerative current generated by the elevating motor 2 flows along the path indicated by the solid arrow in FIG.
That is, the regenerative current is intermittently supplied through the diode D1, the regenerative resistor R, and the switching element Q5, so that regenerative power is consumed by the regenerative resistor R. As a result, the motor power supply circuit 14 and the controller unit 20 are configured. It is prevented that the regenerative power is continuously applied to the electronic component to be destroyed. Further, by changing the duty ratio of the intermittent energization by turning on / off the switching element Q5 of the regenerative resistor circuit section 8, it is possible to control the descent speed to be appropriate, thereby enhancing safety.

(5) When the power to the elevating motor 2 is turned on and the elevating motor 2 unexpectedly rotates in the downward direction due to a failure of the brake mechanism or the like (see FIG. 6). RY1 is on, and in response, the interlock relay contact RY2 is off.

In this state, the elevation motor 2 unexpectedly moves in the downward direction due to the failure of the brake mechanism or the manual release of the brake, even though the elevation signal is not input from the operation unit 18. When the motor 2 rotates, regenerative electric power is generated in the elevating motor 2.

On the other hand, the controller section 20 monitors the detection output of the rotary encoder 12, and if the lifting / lowering motor 2 unexpectedly rotates in the downward direction while the power is on, it is a malfunction of the brake mechanism. As shown in FIG. 6, the motor control unit 6 turns on both the switching elements Q3 and Q4 on the left and right sides of the lifting / lowering motor 2 in response to a command from the controller unit 20, and further switches the remaining switching elements Q1 , Q2 are both turned off. Also, the regenerative resistance control unit 10 turns off the switching element Q5 of the regenerative resistance circuit unit 8.

Thus, a short circuit in which both ends of the elevating motor 2 are short-circuited via the switching elements Q3 and Q4 is formed in the motor driving circuit 4, so that the regenerative current generated in the elevating motor 2 is It flows along the path indicated by the solid arrow in FIG.

That is, when the lifting / lowering motor 2 is unexpectedly rotated in the downward direction due to a failure of the brake mechanism or the like, regenerative electric power is consumed by the rotor inside the lifting / lowering motor 2, and as a result, the motor power supply circuit 14 and controller part 2
It is prevented that the regenerative power is continuously applied to the electronic components constituting 0 or the like to be destroyed. In addition, since the lifting motor 2 is subjected to regenerative braking, the care receiver can be lowered at a safe speed. At this time, even if the operation unit 18 is operated, the controller unit 20 does not accept the input.

(6) Manual lifting motor 2 for power failure
Release the brake and rotate in the downward direction (Fig. 7
When a power failure or the like occurs, the motor power supply circuit 14 has the same connection state as that shown in FIG. That is, as shown in FIG. 7, the power supply relay contact RY1 of the motor drive circuit 4 is turned off, and therefore the interlocking relay contact RY of the regenerative resistor circuit 8 is turned off.
2 is turned on, and each switching element Q1 to Q4
Are both off. Also, the regenerative resistor circuit section 8
Of the switching element Q5 is off.

In this state, when the brake of the lifting / lowering motor 2 is manually released and rotated in the downward direction, regenerative electric power is generated in the lifting / lowering motor 2. In that case, the lifting motor 2
The regenerative current generated in step (1) flows along the path indicated by the solid arrow in FIG. That is, since the regenerative current flows through the diode D1, the regenerative resistor R, and the interlocking relay contact RY2, regenerative power is consumed by the regenerative resistor R. As a result, the electronic components constituting the motor power supply circuit 14, the controller unit 20, and the like. Is prevented from being destroyed by regenerative power. Also,
By adjusting the value of the regenerative resistance R, the cared person can be lowered at a safe speed.

[0045]

The present invention is embodied as in the above-mentioned embodiment, and in the lifting device according to the first aspect and the regenerative power processing method for the lifting device according to the fourth aspect, the lifting motor is moved in the downward direction. If the regenerative power is generated due to a negative slip due to the overload applied to the elevating motor and the regenerative voltage exceeds a preset value, the regenerative resistor circuit Since the switching elements of the section are turned on / off and the regenerative power is consumed by the regenerative resistor, the electronic components constituting the power supply circuit for supplying power to the elevating motor are prevented from being destroyed by the regenerative power. In addition, it is possible to control the down speed to be appropriate by changing the duty ratio of energization by turning on / off the switching element.

In the lifting device according to the second aspect, when the power of the lifting motor is turned on, when the brake mechanism fails or the brake is manually released, the lifting motor unexpectedly moves in the downward direction. Since the motor is short-circuited and the motor is short-circuited and the power is braked, the electronic components of the power supply circuit that supplies power to the motor are prevented from being damaged by regenerative power, and the descent speed is appropriate. Can be controlled so that

In the lifting device according to the third aspect, when the lifting / lowering motor does not operate due to a power failure or the like, the brake mechanism of the lifting / lowering motor is released. When the power is generated, the regenerative current is forced to flow through the regenerative resistor, so that the descent speed can be adjusted to an appropriate value by the value of the regenerative resistor. Also,
Electronic components constituting a power supply circuit for supplying power to the elevating motor due to overvoltage due to the regenerative voltage are prevented from being destroyed by the regenerative power.

[0048]

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main configuration of an electric control system of a lifting device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a detailed configuration of a motor drive circuit and a regenerative resistor circuit section of the elevating device shown in FIG.

FIG. 3 is a circuit diagram showing a state of a motor drive circuit and a regenerative resistor circuit section when a lifting motor is rotated in a rising direction.

FIG. 4 is a circuit diagram showing a connection state of a motor drive circuit and a regenerative resistor circuit section when a lifting motor is normally rotated in a downward direction.

FIG. 5 is a circuit diagram showing a connection state of a motor drive circuit and a regenerative resistor circuit section when the elevating motor is rotated in a descending direction under an overloaded state.

FIG. 6 is a circuit diagram showing a connection state of a motor drive circuit and a regenerative resistor circuit section when the elevating motor unexpectedly rotates in a downward direction due to a failure of a brake mechanism or the like when the motor power supply circuit is turned on.

FIG. 7 is a circuit diagram showing a connection state of a motor drive circuit and a regenerative resistor circuit portion when a brake of a lifting motor is manually released and rotated in a downward direction due to a power failure or the like.

FIG. 8 is a front view showing the entire configuration of the lifting device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 lifting device 2 lifting motor 4 motor drive circuit 6 motor control unit 8 regenerative resistance circuit unit 10 regenerative resistance control unit 12 rotary encoder 14 motor power supply circuit 16 power supply voltage detection circuit 18 operation unit 20 controller unit Q1 to Q5 switching element RY1 power supply Relay contact RY2 Interlocking relay contact R Regenerative resistor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02P 3/12 H02P 3/12 G (72) Inventor Narumichi Murogaki 1048 Ojidomazuma, Kazuma, Osaka Prefecture Matsushita Electric Works Ryoji Enozono, Inventor Ryoji Enozono 1048, Kazuma, Kazuma, Osaka Prefecture Matsushita Electric Works F-term (reference) 3F002 CA06 EA09 GB02 3F204 AA02 BA02 CA05 FA04 FB05 FC08 FD02 4C040 HH01 JJ02 JJ07 5H530 AA12 BB25 CC23 CC26 CC27 CD24 CD34 CE15 DD02 DD14 EE01 EE07

Claims (4)

[Claims] A motor drive circuit for driving a lifting motor up and down is connected to a regenerative resistor circuit section having a regenerative resistor and a switching element for supplying a regenerative current to the regenerative resistor. Regenerative voltage detecting means for detecting the generated regenerative voltage, and a regenerative resistance control unit for turning on / off the switching element of the regenerative resistance circuit unit when the value of the regenerative voltage exceeds a predetermined value. And a regenerative current generated by the elevating motor is supplied to the regenerative resistor to consume regenerative power. A lifting / lowering motor provided with a brake; a power supply for supplying power to the lifting / lowering motor being turned on; and a release signal for releasing the restrained state of the lifting / lowering motor by the brake is not input. Connection between the constrained rotation detecting means for detecting that the motor for rotation has been rotated in the descending direction and the motor drive circuit such that both ends of the elevating motor are short-circuited when the constrained rotation detecting means detects the state. 2. The elevating device according to claim 1, further comprising: a short circuit generating means for switching the power generation and braking. 3. A regenerative resistor including a means for supplying a regenerative current to the regenerative resistor when the elevating motor is rotated in a downward direction while a power supply for supplying power to the elevating motor is turned off. 3. The lifting device according to 1 or 2. 4. A regenerative power processing method for processing regenerative power generated by a lifting motor, wherein a regenerative voltage generated by the raising / lowering motor is monitored, and when a value of the regenerative voltage exceeds a predetermined value set in advance. A switching element connected to a motor drive circuit for driving the elevating motor and having a regenerative resistor and a switching element for supplying a regenerative current to the regenerative resistor is turned on / off, and the regenerative current is converted to the regenerative resistor. A regenerative power processing method for an elevating device, characterized in that regenerative power is consumed by energizing.