JPH11150966A - Controller for electromagnetic brake mechanism of motor to be controlled on speed - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize a time lag, at the time of starting a motor fitted with a nonexcitation operating electromagnetic brake to be used for elevators and so forth, and to prevent the load of an elevator from falling. SOLUTION: An apparatus 11 controls the speed of a motor M fitted with a nonexcitation operating type electromagnetic brake 3 by a speed control unit 5 containing a drive circuit, supplies power to the electromagnetic brake 3 from a power source 8 by a switch section 7, and releases its braking at the time of starting the motor M. Here, a voltage the same as a command value of a voltage to be applied to the motor equal to a voltage by which the motor M starts a load, is set beforehand in a setter, on the occasion of starting the motor M, and the command value (a voltage 9) of a voltage to be outputted from the speed control unit 5 and applied to the motor M is compared with the set voltage in the switch section 7, and only when the voltage applied to the motor M becomes the set voltage or higher, power is supplied from the power source 8 to the electromagnetic brake 3, and the braking is released to start the motor M.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an electromagnetic braking mechanism of a motor whose speed is controlled, and more particularly to a control device for conveying a load in a vertical direction and starting the motor having the electromagnetic braking mechanism. The present invention relates to a device for controlling the electromagnetic braking mechanism while preventing the device from falling.

[0002]

2. Description of the Related Art Conventionally, as a control device of an electromagnetic braking mechanism, which is a mechanical holding mechanism, provided in such a type of speed-controlled electric motor, there is, for example, the one shown in the block diagram of FIG. The electromagnetic braking mechanism is directly connected to an output shaft of the electric motor, and is controlled by the control device in conjunction with the electric motor.

In FIG. 4, a control device 1 has a speed detector 2, a non-excited operation type electromagnetic brake 3 arranged to be coupled to an output shaft thereof, and a load 4.
Is compared with a speed signal detected by the speed detector 2 by a speed control unit 5 including a drive circuit, and the motor M is driven by a drive circuit (not shown). Control the speed of M. Then, when the electric motor M is started, the control device 1 issues an operation start signal 6
Is input to the speed control unit 5 and the switch unit 7 at the same time, power is supplied from the power supply 8 to the electromagnetic brake 3 by the switch unit 7, and the braking of the electromagnetic brake 3 is released. The motor 5 is operated by the unit 5.

[0004]

However, in such a conventional electromagnetic braking mechanism control apparatus 1 for a speed-controlled electric motor, as shown in FIG. When input to the speed control unit 5 and the switch unit 7, the electromagnetic brake 3 is released almost at the same time as in b).

[0005] Therefore, when the motor M is used as a drive source of a lifting device or the like and a large load 4 that rotates the motor M in the reverse direction is connected to the motor M, d) When the motor M is rotated in the reverse direction (downward direction by the elevating device) for a short time at the start of operation, or when the speed detector 2 cannot determine the rotation direction, the load M However, there is a problem that if the motor is turned at a speed higher than the set speed, the motor continues to rotate in the opposite direction.

Therefore, as shown in FIG. 5C, a time delay occurs after the operation start signal 7 is input and the electromagnetic brake 3 is released until the torque of the electric motor M is generated. Then, the output shaft of the electric motor M is rotated by the load 4 at a speed higher than the set speed. In particular, in the case where the motor M controls the speed of a single-phase induction motor, there is only one control opportunity in a half power cycle, and if the response of the control is too fast, the speed is not stabilized. Control is performed with a delay of several cycles. Therefore, this time delay is large and the above-mentioned problem is remarkable.

The problem is that when the speed of the electric motor M is controlled, particularly when the set speed is low, or when the set speed is gradually increased from a low speed to reduce a mechanical shock. (Soft start operation)
Appears prominently.

[0008] The present invention has been made in view of such a point,
The object of the present invention is to solve the above-mentioned problem and to minimize the occurrence of time delay of the electric motor at the time of starting when an electric motor having a non-excited operation type electromagnetic braking mechanism is used as a driving source of the elevating device or the like. It is another object of the present invention to provide a control device for an electromagnetic braking mechanism of a motor whose speed is controlled to prevent the load of the lifting device from dropping.

[0009]

According to the present invention, there is provided a speed control unit including a drive circuit for an electric motor having a speed detector and a non-excitation type electromagnetic braking mechanism. By comparing the set speed signal with the speed signal detected by the speed detector to control the speed of the electric motor, and at the time of starting the electric motor, the switch unit supplies electric power from the power supply to the electromagnetic braking mechanism. The control device for supplying and releasing the braking of the electromagnetic braking mechanism is as follows.

(1) When the motor is started, the switch unit controls the voltage command value output from the speed control unit and applied to the motor, and the applied voltage instruction value corresponding to the motor to start the load. By comparing with a set voltage that can be arbitrarily set, when the indicated value of the voltage applied to the electric motor is equal to or higher than the set voltage, the switch unit supplies power from the power supply to the electromagnetic braking mechanism. And releasing the braking.

(2) The speed control unit compares and amplifies a speed setting circuit for setting the speed of the electric motor, and a speed signal detected by the speed detector from the speed signal from the speed setting circuit. A comparison amplifier circuit that outputs a motor applied voltage indication value, a power supply synchronization signal generation circuit that generates a sawtooth signal synchronized with a power supply frequency, and a difference between the sawtooth wave signal from the power supply synchronization signal generation circuit and the comparison amplification circuit. It comprises a comparator for comparing signals and outputting a trigger signal, and the driving circuit.

On the other hand, when the output of the comparison amplifier circuit is large, when the motor application voltage is set to be large, the switch section includes a release start voltage setter, a release start set voltage from the setter, and the release start voltage setter. A braking control comparison circuit that compares the motor application voltage instruction value from the comparison amplification circuit and outputs a signal when the signal from the comparison amplification circuit becomes larger than the set voltage; and an output signal of the braking control comparison circuit. And a gate circuit for driving the electromagnetic braking mechanism driving circuit, and the electromagnetic braking mechanism driving circuit.

When the electric motor is started, the braking control comparison circuit of the switch unit sets the voltage, which is the motor application voltage instruction value from the comparison amplification circuit of the speed control unit, equal to or higher than the release start set voltage. In this case, power is supplied to the electromagnetic braking mechanism by the electromagnetic braking mechanism driving circuit through the gate circuit of the switch section, and the braking is released.

Since the present invention is configured as described above, when the motor is started, the switch unit generates an equivalent voltage corresponding to the voltage applied to the motor and generated in the speed control unit. Comparing the torque command value of the signal with a setting signal corresponding to a setting voltage that can be arbitrarily set so that the motor can start a load, and when the applied voltage equivalent signal becomes equal to or more than the setting signal, the switch The unit can also supply power to the electromagnetic braking mechanism from a power supply to release the braking of the electromagnetic braking mechanism.

For this reason, when starting the electric motor, it is possible to minimize the occurrence of time delay of the electric motor.
In addition, when a load is applied in a direction opposite to the driving direction, the electric motor can be started without rotating in the reverse direction. The electromagnetic braking mechanism used for this control is
An excitation operation type may be used.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the drawings. (First Embodiment) FIG. 1 is a block diagram showing the construction of a first embodiment of an electromagnetic braking mechanism control device for a speed-controlled electric motor according to the present invention. FIG. 6 is a timing chart showing an operation.

Referring to FIG. 1, a control device 11 has a speed detector 2 and a non-excited operation type electromagnetic brake 3 arranged to be coupled to an output shaft of the motor. For M, the speed control unit 5 including the drive circuit compares the set speed signal with the speed signal detected by the speed detector 2 and amplifies the difference signal. The circuit drives and controls the motor M so that the speed of the motor M becomes the set speed.

When the electric motor M is started, the control device 11 simultaneously inputs an operation start signal 6 to the speed control unit 5 and the switch unit 7 and simultaneously operates the switch unit 7.
And a signal corresponding to the voltage applied to the motor M output from the speed control unit 5 is input to the switch unit 7.
A set voltage (ie, a set applied voltage) that can start a load as a torque command value of the electric motor M set in
When the signal 9 corresponding to the voltage applied to the electric motor M becomes equal to or greater than the set signal, the switch unit 7 supplies power from the power supply 8 to the electromagnetic brake 3. Then, the braking of the electromagnetic brake 3 is released. Thereafter, the motor M is operated by the drive circuit in the speed control unit 5.

The timing of the operation of each part of the control device 11 when the motor M is started will be described with reference to FIG. When the electric motor M is started, the operation start signal 6 is set to a)
As shown in (c), when the signals are simultaneously input to the speed control unit 5 and the switch unit 7, as shown in c), the speed control unit 5
Starts operation with a slight time delay, and the signal voltage output from the speed control unit 5 and corresponding to the voltage applied to the electric motor M gradually increases.

The signal 9 corresponding to the voltage applied to the motor M from the speed controller 5 input to the switch unit 7 is equal to or greater than the set signal corresponding to the set voltage set in the switch unit 7. Then, as shown in b), the power is supplied from the power source 8 to the electromagnetic brake 3 by the switch section 7, the electromagnetic brake 3 is excited, and the braking is released. Thus, when the electric motor M is used as a drive source of an elevating device or the like, the load is conveyed in the ascending direction without dropping the load of the elevating device as shown in d).

As described above, the release operation of the electromagnetic brake 3 is determined by the starting torque of the electric motor M (corresponding to the applied voltage).
Is performed after the load starting torque (corresponding to the set voltage) as the torque command value of the electric motor M is increased, the electric motor M can be started without being reversed by the load 4. Therefore, there is almost no time delay from when the braking of the electromagnetic brake 3 is released to when the electric motor M is actually started.

(Second Embodiment) FIG. 3 is a block diagram showing a configuration of a second embodiment of the control device of the present invention. 3, the control device 20 includes a speed control unit 21 including a drive circuit 28 and a switch unit 31 including an electromagnetic brake drive circuit 35.

The speed control unit 21 includes a speed setting circuit 23 for setting the speed of the electric motor M,
And a comparison amplifier circuit 24 that compares the set speed signal from the motor with the motor speed signal detected by the speed detector 2 coupled to the motor M, amplifies the difference signal, and outputs the amplified signal as a motor applied voltage indication value. A power synchronizing signal generating circuit 25 for generating a sawtooth signal synchronized with the frequency of the AC power source, and comparing the sawtooth signal from the power synchronizing signal generating circuit 25 with the voltage signal from the comparing and amplifying circuit 24 to generate a trigger. It comprises a comparator 26 for outputting a signal and the drive circuit 28.

On the other hand, the switch section 31 compares the release start setting voltage from the setting circuit 32 with the motor application voltage instruction value from the comparison amplifier circuit 24, and When the signal from the circuit 24 becomes larger than the set voltage (when the applied voltage to the electric motor becomes larger than the set applied voltage), a braking control comparing circuit 33 for outputting a signal; A gate circuit 34 that operates in response to an output signal of the comparison circuit 33 and fires a thyristor 35a in the electromagnetic brake drive circuit 35
And the electromagnetic brake drive circuit 35.

The release start voltage setter 32 preliminarily adjusts a voltage at which the motor M can start a load to be the same as a motor application voltage instruction value for instructing the motor M to apply a load. deep. Then, when the electric motor M is started, the braking control comparison circuit 33 in the switch unit 31 changes the motor application voltage instruction value 29 from the comparison amplification circuit 24 of the speed control unit 21 to the release start set voltage. At this time, the thyristor 35a is ignited into the electromagnetic brake driving circuit 35 through the gate circuit 34 in the switch unit 31, and the power is supplied from the power supply to the electromagnetic brake 3 to release the braking. Like that.

In this manner, similarly to the first embodiment, the release operation of the electromagnetic brake 3 is performed after the starting torque of the electric motor M becomes larger than the load starting torque as the torque command value of the electric motor M. Then, the motor M
Can be started without being reversed by the load 4. For this reason, the time delay from the release of the braking of the electromagnetic brake 3 to the actual start of the electric motor M is also substantially eliminated.

If the control device including the speed control of the electric motor M is manufactured by using a microcomputer,
If the data of the torque generated in the electric motor M is collected in advance, it can be easily realized.

Note that the technology of the present invention is not limited to the technology in the above-described embodiment, and may be implemented by means of another mode that performs the same function. Various changes and additions are possible.

[0029]

As is apparent from the above description, according to the electromagnetic braking mechanism control device for a speed-controlled electric motor of the present invention, when the electric motor having the non-excited operation type electromagnetic brake is started, the speed is controlled by the switch section. When the voltage output from the control unit and applied to the motor is compared with a set voltage at which the motor can start a load as a torque command value, when the voltage applied to the motor becomes equal to or higher than the set voltage, The switch supplies power from the power supply to the electromagnetic braking mechanism to release the braking, so that the occurrence of time delay of the electric motor can be minimized. Further, when an electric motor having a non-excited operation type electromagnetic braking mechanism is used as a drive source of the elevating device, it is possible to prevent the load of the elevating device from dropping.

An electric motor provided with a non-excited operation type electromagnetic braking mechanism, which is speed-controlled and can be started without reverse rotation when the load is applied in the direction opposite to the driving direction. This effect is effective in preventing a load from dropping in a lifting device driven by an induction motor having the electromagnetic braking mechanism as a driving source, particularly when performing a soft start. Further, the speed detector only needs to detect the speed in one direction, so that the size can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram showing a first embodiment of an electromagnetic braking mechanism control device for a speed-controlled electric motor according to an embodiment of the present invention.

FIG. 2 is a timing chart showing the operation of each unit of the control device when the electric motor of FIG. 1 is started.

FIG. 3 is a block diagram showing a second embodiment of the electromagnetic brake mechanism control device for a speed-controlled electric motor according to the embodiment of the present invention;

FIG. 4 is a block diagram showing a configuration of a conventional electromagnetic braking mechanism control device for a speed-controlled electric motor.

FIG. 5 is a timing chart showing the operation of each part of the conventional control device when the electric motor of FIG. 4 is started.

[Explanation of symbols]

 1, 11, 20 Electromagnetic braking mechanism control device 2 Speed detector 3 Electromagnetic brake 4 Load 5, 21 Speed control unit 6 Operation start signal 7, 31 Switch unit 8 Power supply 9, 29 Signal corresponding to motor applied voltage 23 Speed setting circuit Reference Signs List 24 Comparison amplification circuit 25 Power supply synchronization signal generation circuit 26 Comparator 28 Drive circuit 28a Triac 32 Release start voltage setting device 33 Braking control comparison circuit 34 Gate circuit 35 Electromagnetic brake drive circuit 35a Thyristor M motor

Claims (2)

[Claims] An electric motor having a speed detector and having a non-excited operation type electromagnetic braking mechanism is provided with a set speed signal and a speed signal detected by the speed detector by a speed control unit including a drive circuit. A device for controlling the speed of the electric motor and supplying power to the electromagnetic braking mechanism from a power source by a switch unit at the time of starting the electric motor, thereby releasing the braking of the electromagnetic braking mechanism. When starting, the switch unit compares the voltage output from the speed control unit and applied to the motor with a set voltage at which the motor can start a load as a torque command value, and is applied to the motor. When the voltage applied to the electromagnetic brake mechanism becomes equal to or higher than the set voltage, power is supplied from the power supply to the electromagnetic braking mechanism, and the braking is released. Electromagnetic braking mechanism control system of motivation. 2. An electric motor having a speed detector and having a non-excited operation type electromagnetic braking mechanism, a speed control unit including a drive circuit controls a set speed signal and a speed signal detected by the speed detector. A device for controlling the speed of the electric motor and supplying power to the electromagnetic braking mechanism from a power source by a switch unit at the time of starting the electric motor, thereby releasing the braking of the electromagnetic braking mechanism. A control section for comparing and amplifying a speed setting circuit for setting the speed of the electric motor, a set speed signal from the speed setting circuit and a speed signal detected by the speed detector, and outputting a motor applied voltage instruction value; A comparison amplification circuit, a power supply synchronization signal generation circuit that generates a sawtooth signal synchronized with the power supply frequency, and a ratio of the sawtooth wave signal from the power supply synchronization signal generation circuit to the difference signal from the comparison amplification circuit. And a switch that outputs a trigger signal and the drive circuit, wherein the switch unit sets a voltage at which the motor can start a load, and a release start voltage setter, and a release start from the setter. A braking control comparison circuit that compares a set voltage with a motor applied voltage instruction value from the comparison amplification circuit and outputs a signal when the signal from the comparison amplification circuit is greater than the set voltage; A gate circuit that operates according to an output signal of the circuit and drives an electromagnetic braking mechanism driving circuit; and the electromagnetic braking mechanism driving circuit. When the electric motor is started, the braking control comparison circuit of the switch unit controls the speed. When a voltage that is a motor application voltage instruction value from the comparison amplifier circuit of the control unit becomes equal to or higher than the release start set voltage, the gate circuit of the switch unit is controlled. Through the supply of power by electromagnetic braking mechanism driving circuit to the electromagnetic brake mechanism, the electromagnetic brake mechanism control unit for an electric motor which is speed controlled, characterized in that to release the brake.