JPH08308283A - Motor speed controller - Google Patents

Abstract

PURPOSE: To obtain a motor speed controller which can control the field weakening amount for a load without operating a base rotating speed at a constant speed, limit the necessary torque for the load to the necessary minimum limit and further prevent the runaway of the motor to assure the safety. CONSTITUTION: A motor speed controller comprises an acceleration monitoring circuit 33 for monitoring the accelerating state of the rotating speed of a motor due to the speed feedback, and an incremental speed command outputting circuit 35 for outputting an incremental speed command responsive to the monitored result of the circuit 33, thereby outputting a control speed command based on the addition of the incremental speed command output from the circuit 35 and the speed command generated from a speed command unit 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor speed control device which is suitable for use in, for example, a crane device to improve operating efficiency.

[0002]

2. Description of the Related Art In a crane device for hoisting and transporting material, hoisting material is hoisted and transported by hoisting equipment, the material suspended at a predetermined position is hung down, and the operation of returning to the material hoisting position is repeated. In the one-cycle operation of the crane device that performs such an operation, the operation is performed with the material suspended by the hoist during the forward operation, and the operation is performed without the material suspended during the return operation. The load varies greatly with time. It is desirable from the economical point of view that the time required for one cycle operation of the crane device is as short as possible, and at the time of resumption, only the weight of the lifting device is a load and a constant light load, so high-speed operation by constant output control is required. It Moreover, since the weight of the suspended material is not uniform, it is desirable to control the lightweight material at a high-speed operation as much as possible even when it is going forward.

Therefore, when the crane device is hoisting the material, both the voltage and the current have a positive polarity, and when the material is hoisted, when the braking is applied, the voltage is positive and the current is negative, and the material is hoisted. When the braking is applied while the vehicle is on, the regions where the voltage is negative and the current is positive are used. As a result, a constant output control is performed in which the load amount is determined depending on whether the material to be suspended is heavy or light and the operating speed is changed.

As is well known, the speed N of a motor is N =
It is represented by (Ea-Ia · Ra) / K · φ. E here
a is the armature voltage, Ia is the armature current, Ra is the resistance value of the resistor inserted in series in the armature, K is a constant, and φ is the magnetic flux generated by the field current.

As a method for controlling the rotation speed N of the electric motor, there are an armature voltage method for controlling the armature voltage Ea, a resistance control method for controlling the resistance value Ra, and a field control method for controlling the magnetic flux φ. It is possible to control the rotation speed N by using either of them. However, when controlling the rotation speed N in a wide range, the above-mentioned methods are often used in combination.

FIG. 26 is a functional block diagram showing the configuration of a conventional electric motor speed control device disclosed in Japanese Patent Publication No. 6-48913. In the figure, 1 is an electric motor consisting of an armature 1a and a field winding 1b, 2 is a three-phase AC power supply, and 3 is a thyristor converter that rectifies the output current of the three-phase AC power supply 2 and supplies it to the armature 1a of the electric motor 1. It is a vessel. 4 is a current transformer that detects the output current of the three-phase AC power supply 2, that is, the armature current Ia, 5 is a voltage control amplifier that controls the output voltage of the thyristor converter 3, that is, the armature voltage Ea, and 6 is a voltage control amplifier 5. The current control amplifier for inputting the voltage command E _A , 7 for the speed control amplifier for inputting the current command I _A to the current control amplifier 6, 8 for the back electromotive voltage of the motor 1, that is, the armature voltage Ea
Voltage sensor for feeding back the voltage to the voltage controlled amplifier 5,
Reference numeral 9 is a current sensor for feeding back the armature current Ia detected by the current transformer 4 to the current control amplifier 6, 10 is a finger speed generator for detecting the rotation speed N of the electric motor 1, and 11 is a finger speed generator 10. This is a speed sensor that feeds back the generated rotation speed N to the speed control amplifier 7.

Reference numeral 12 is an AC power source, and 13 is a rectified output current of the AC power source 12 and applied to a field winding 1b of the electric motor 1 by a field current I.
A field thyristor supplied as b. Reference numeral 14 is a speed command device such as a master operation switch for generating a speed command N _A for the electric motor 1. Reference numeral 19 denotes a rated voltage commander that generates a rated voltage command E _R according to the armature voltage that shifts from the speed feedback control to the field control, that is, the base speed N _R of the electric motor 1. 20 is an automatic field control device for comparing the nominal voltage command E _R and armature voltage Ea, the armature voltage Ea is above the rated voltage command E _R, the armature voltage Ea and the value of the rated voltage command E _R matches A field weakening signal C for causing the field weakening signal C is output to the field thyristor 13.
Reference numeral 21 denotes a variable controller inserted between the automatic field controller 20 and the field thyristor 13, and based on the maximum limit speed N _B , the field weakening signal C is set so as not to weaken the field more than necessary. Is restricted. Incidentally, the thyristor converter 3, the voltage control amplifier 5, the current control amplifier 6, the speed control amplifier 7,
The finger speed generator 10 constitutes a speed feedback control system,
The field thyristor 13 and the automatic field control device 20 form a field control system.

Reference numeral 23 is a current transformer for detecting the field current Ib, 2
A current sensor 4 feeds back the field current Ib detected by the current transformer 23 to the automatic field controller 20. Two
Reference numeral 5 is a maximum priority circuit that compares the armature voltage Ea with the field current Ib and outputs the larger one to the automatic field controller 20. When the armature voltage Ea reaches the rated voltage command E _R , the field current Ib is output. It is tuned to output matching signals.

Reference numeral 40 is an armature current Ia from the current sensor 9.
Is a programmable controller that outputs a speed command N _C for control to the speed control amplifier 7 based on the speed command N _A from the speed command device 14, and includes an AD converter 41, an AD converter 42, and a DA converter. 43 and a CPU, that is, a calculation unit 50. The arithmetic unit 50 averages and averages the gate 51 that closes (turns on) when the base rotation speed, that is, the base rotation speed N _R , and the digital armature current Ia ′ via the AD converter 42 and the gate 51. Average value processing circuit 52 for outputting armature current Ia ″
And the speed command N for acceleration corresponding to the average armature current Ia "
Function simulation circuit 53 that determines _D and speed command N _{D for} acceleration
Signal generating circuit 54 for converting the torque into the tilt speed command N _E
And the digital speed command N _A 'through the AD converter 41
And a data addition unit 55 for adding the tilt speed command N _E ,
The operation control circuit 56 has a built-in automatic deceleration circuit and outputs a digital speed command N _C ′ based on the addition output of the data addition unit 55. Reference numeral 58 is a comparison circuit for comparing the output of the function simulation circuit 53 and the armature current.

The function simulation circuit 53 stores in advance the relationship between the armature current Ia corresponding to the torque T and the rotation speed N, and the speed-up component speed command N _D corresponds to the maximum limit speed N _B. are doing.

Next, the operation will be described. First, when the maximum notch or less of the speed commander 14 is selected, the gate 51 is opened (OFF), so the speed command N _A input to the programmable controller 40 is the AD converter 41 and the operation control circuit 56. , The speed command N _C is directly input to the speed control amplifier 7 via the DA converter 43. Therefore, the rotation speed N of the electric motor 1 is determined by the speed commander 14
It is controlled by the speed command N _A from. At this time, since the armature voltage Ea is equal to or lower than the rated voltage command E _R , the field thyristor 13 causes the maximum value priority circuit 25 to cause the field current Ib.
Is controlled to be constant.

On the other hand, when the maximum notch of the speed command device 14 is selected, the speed command N corresponding to the base rotation speed N _R is selected.
_A is supplied to the programmable controller 40, and accelerates the electric motor 1 to the base rotation speed N _R as described above. At this time, the armature current Ia detected by the current sensor 9 is always input to the programmable controller 40,
Further, when the rotation speed of the electric motor 1 reaches the base rotation speed N _R , the gate 51 is closed (turned on), so that the digital armature current Ia ′ is input to the average value processing circuit 52. The digital armature current Ia ′ becomes the average armature current Ia ″ by the average value processing circuit 52, and is added to the digital speed command N _A ′ corresponding to the base rotation speed N _R by the data addition unit 55, and further the operation control circuit 56. And DA converter 43
Is output from the programmable controller 40 as a speed command N _C for control (hereinafter, this control is referred to as efficiency control).

In response to this speed command N _C , the speed control amplifier 7 raises the output voltage of the thyristor converter 3 above the rated voltage and controls the rotational speed N of the electric motor 1 in the direction of increasing it. At this time, the maximum value priority circuit 25 outputs the armature voltage E
Since a is preferentially output, the automatic field control device 20 shifts to the constant back electromotive force control, and the field current Ib gradually increases.
Is decreased and the rotation speed N is further increased. Then, the rotational speed N is speed command N _C field current Ib until matching is decreased from the programmable controller 40, rotation speed N is controlled to a speed corresponding to the speed command N _C by the speed control system is stabilized.

FIG. 27 is a characteristic diagram showing a torque-speed characteristic of the electric motor 1 in which the vertical axis represents the torque T and the horizontal axis represents the rotation speed N. 81 is a plus load characteristic, and T ₁ and T ₂ are maximum limit speeds. Torque required for heavy load generated by N _B1 , T
₃ and T ₄ indicate torques required at a light load generated by the maximum limit speed N _B2 . As is clear from FIG. 27, the load of the electric motor 1 is heavy and the torque T ₁ or the torque T
_{When 2} is required, the rotation speed N of the electric motor 1 is variably controlled up to the maximum limit speed N _B1 obtained from the comparison circuit 58, and the load of the electric motor 1 is light and the torque T ₃ or T _{4 is applied.}
Motor 1 up to the maximum speed limit N _B2
The rotation speed N of is variably controlled.

[0015]

Since the conventional motor speed control device is constructed as described above, the load must be detected by reaching the base speed and the field must be determined according to the detection result. However, once to detect the load,
There is a problem that it is necessary to operate at a constant speed at the base speed.

In addition, since the accuracy of the load detection becomes worse as the load detection is performed in a shorter time, from the viewpoint of safety, the detected load is set to be larger than the actual detected load to reduce the field weakening amount, that is, the rotation speed. There was also a problem that it had to be controlled in the direction of not raising.

The present invention has been made in order to solve the above-mentioned problems, and the field weakening amount with respect to the load can be controlled without performing constant speed operation at the base speed, and the required torque with respect to the load can be minimized. Limit to improve operating efficiency,
Another object of the present invention is to obtain an electric motor speed control device capable of preventing runaway of the electric motor and ensuring safety.

[0018]

According to a first aspect of the present invention, there is provided an electric motor speed control device for controlling an armature voltage of the electric motor according to a deviation between a speed command generated by a speed command device and a rotation speed of the electric motor. A speed feedback control system, a field control system for comparing the armature voltage and a field current of the electric motor to control the field current so that the armature voltage does not exceed a rated voltage, and the electric motor AD for converting the speed feedback of the digital to the digital speed feedback
A converter, a speed-up monitoring circuit that monitors the state of speedup of the rotation speed of the electric motor by the speed feedback, and a speed-up speed that outputs a speed-up speed command according to the monitoring result of the speed-up monitoring circuit. A command output circuit, for controlling according to the load of the electric motor based on the addition of the speed increase command output by the speed increase speed command output circuit and the speed command generated by the speed commander. And a programmable controller that outputs a speed command to the speed feedback control system.

An electric motor speed control device according to a second aspect of the present invention includes an acceleration monitor circuit for monitoring the amount of change in the rotational speed of the electric motor in the process of weakening the field.

An electric motor speed control device according to a third aspect of the present invention stores a speed command for control when hoisting a motor of a crane, and outputs the stored speed command for control when hoisting the crane. It is equipped with a programmable controller.

The motor speed control device according to the invention of claim 4 monitors that the rotation speed of the motor is equal to or lower than the base rotation speed when the efficiency control is not performed, and outputs an emergency stop signal according to the monitoring result. It is provided with a programmable controller having a base rotation speed monitoring means for outputting.

An electric motor speed control device according to a fifth aspect of the present invention compares the speed feedback trace data with the speed command data of the speed command device to determine whether or not the current rotation speed is a controlled speed. A programmable controller having a control speed monitoring means for monitoring and outputting an emergency stop signal according to the monitoring result is provided.

In the motor speed control device according to the sixth aspect of the present invention, when the speed commander is set to the zero notch during operation of the motor, the direction of control of the rotation speed of the motor by digital speed feedback is directed to zero. It is provided with a programmable controller having a control direction monitoring means for monitoring whether there is an emergency stop signal and outputting an emergency stop signal according to the monitoring result.

In the motor speed control device according to the invention of claim 7, an AD converter for converting the armature voltage feedback in the speed feedback into a digital armature voltage feedback, and the speed commander having a zero notch during operation of the motor. At this time, it is provided with a programmable controller having an armature voltage monitoring means for monitoring whether or not the armature voltage is going toward zero and outputting an emergency stop signal according to the monitoring result.

An electric motor speed control device according to an eighth aspect of the present invention includes an AD converter for converting armature current feedback in speed feedback into digital armature current feedback, and a speed command device during hoisting operation of a motor for a crane. When the notch is set to zero, it is monitored that the armature current controlled by the armature current feedback is controlled to a negative current value, and when the speed commander is set to zero notch during the lowering operation, Programmable with armature current polarity monitoring means for monitoring that the armature current controlled by the armature current feedback is controlled to a positive current value and outputting an emergency stop signal according to the monitoring result. It is equipped with a controller.

An electric motor speed control device according to a ninth aspect of the present invention monitors whether or not the armature current during operation of the electric motor continuously maintains a value near zero, and an emergency stop signal is output according to the result of the monitoring. And a programmable controller having an armature current value monitoring means for outputting

According to a tenth aspect of the present invention, in the electric motor speed control device, both the hoisting operation and the hoisting operation based on either or both of the hoisting command and the hoisting command by the speed commander during the operation of the electric motor for the crane. Alternatively, it is provided with operation monitoring means for monitoring the number of times of one operation and outputting an emergency stop signal according to the monitoring result.

According to the eleventh aspect of the present invention, in the motor speed control device, whether the armature voltage or the armature current controlled by the speed feedback becomes zero after a predetermined time has elapsed since the speed commander was set to the zero notch. It is provided with a programmable controller having a speed feedback monitoring means for monitoring whether or not the emergency stop signal is output according to the monitoring result.

According to a twelfth aspect of the present invention, in the motor speed control device, when the speed commander is set to the zero notch during operation of the motor, the amount of change in the speed which is controlled toward zero by digital speed feedback. Is provided and a speed change amount monitoring means for outputting an emergency stop signal according to the monitoring result is provided.

In the motor speed control device according to a thirteenth aspect of the present invention, the armature is controlled toward zero by digital armature voltage feedback when the speed commander has a zero notch during operation of the motor. An armature voltage change amount monitoring means for monitoring the voltage change amount and outputting an emergency stop signal according to the monitoring result is provided.

[0031]

According to another aspect of the present invention, the electric motor speed control device monitors the speed increasing state of the electric motor rotation speed by speed feedback, and outputs the speed increasing component speed command based on the monitored speed increasing state. Then, the speed command for control is output based on the addition of the speed command for the increased speed and the speed command generated by the speed commander, the electric motor is controlled, and the torque at the rotational speed is adjusted to the minimum necessary value corresponding to the load. Automatically adjust to the required torque.

According to another aspect of the present invention, the motor speed control device monitors the amount of change in speed increase of the electric motor by speed feedback, and outputs a speed-increasing speed command based on the monitored amount of change. , The speed command for control is output based on the addition of the speed command for increasing speed and the speed command generated by the speed commander, the electric motor is controlled, and the torque at the rotation speed is adjusted to the minimum necessary value corresponding to the load. Automatically adjust to the required torque.

In the electric motor speed control device according to the third aspect of the present invention, since the load during hoisting and the load during hoisting do not change in the crane, the speed command for control during hoisting of the crane is stored, At the time of lowering the crane, the rotation speed of the electric motor reaches the base rotation speed, and the rotation speed of the electric motor is controlled by using the stored speed command for control, and the torque at the rotation speed is adjusted to the minimum required value corresponding to the load. Automatically adjust to the required torque.

The base rotation speed monitoring means in the invention of claim 4 monitors whether or not the rotation speed of the electric motor is equal to or lower than the base rotation speed when the efficiency control is not performed, and according to the result of the monitoring, the base rotation speed monitoring means. An emergency stop signal is output to prevent runaway of the electric motor and ensure safety based on the rotation speed.

The control speed monitoring means in the invention of claim 5 compares the trace data of the speed feedback with the speed command data of the speed command device, and the current rotational speed is determined from the relationship between the speed command data and the trace data. It monitors whether or not it is in an expected state, outputs an emergency stop signal for the electric motor according to the result of the observation, prevents runaway of the electric motor, and ensures safety.

According to a sixth aspect of the present invention, in the control direction monitoring means, the direction in which the rotational speed of the electric motor is controlled by digital speed feedback is directed to zero when the speed commander has a zero notch during operation of the electric motor. Monitor for
Outputs an emergency stop signal of the electric motor according to the monitoring result,
Prevent runaway of the electric motor and ensure safety.

According to a seventh aspect of the present invention, in the armature voltage monitoring means, the direction in which the armature voltage of the motor is zero controlled by the digital armature voltage feedback when the speed commander is set to the zero notch during operation of the motor. It is monitored whether or not it is heading for, and an emergency stop signal of the electric motor is output according to the result of the observation, runaway of the electric motor is prevented, and safety is secured.

In the armature current polarity monitoring means according to the invention of claim 8, when the speed commander is set to the zero notch during the hoisting operation of the motor for the crane, the armature current controlled by the digital armature current feedback is It is monitored whether or not the current value in the negative direction is controlled, and when the speed commander is set to zero notch during the lowering operation,
It is monitored whether the armature current controlled by the digital armature current feedback is controlled to a current value in the positive direction, and an emergency stop signal of the motor is output according to the monitoring result to prevent the motor from running away. And ensure safety.

According to the ninth aspect of the invention, the armature current value monitoring means monitors whether or not the armature current during operation of the electric motor is continuously maintained near zero, and the electric motor of the electric motor is detected according to the result of the monitoring. An emergency stop signal is output to prevent runaway of the motor and ensure safety.

According to the tenth aspect of the invention, the operation monitoring means monitors the number of times of hoisting operation and / or hoisting operation by the speed command device during the operation of the electric motor to detect an abnormal operation of the operator with respect to the speed command device. Judgment is made and an emergency stop signal of the electric motor is output to prevent runaway of the electric motor and ensure safety.

The speed feedback monitoring means in the invention of claim 11 determines whether or not the armature voltage or the armature current controlled by the speed feedback becomes zero after a predetermined time has elapsed from the time when the speed commander was set to the zero notch. This is monitored, and an emergency stop signal of the electric motor is output according to the result of the observation to prevent runaway of the electric motor and ensure safety.

According to the twelfth aspect of the present invention, the speed change amount monitoring means is in a state in which the rotational speed of the electric motor is controlled by digital speed feedback in the zero direction when the speed commander has a zero notch during operation of the electric motor. The amount of change is monitored, an emergency stop signal of the electric motor is output according to the monitoring result, runaway of the electric motor is prevented, and safety is ensured.

According to the thirteenth aspect of the present invention, the armature voltage change amount monitoring means is controlled toward the zero direction by the digital armature voltage feedback when the speed commander is set to the zero notch during operation of the electric motor. The amount of change in the armature voltage is monitored, and an emergency stop signal for the motor is output according to the monitoring result to prevent runaway of the motor and ensure safety.

[0044]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. 1 is a functional block diagram showing a configuration of an electric motor speed control device according to a first embodiment of the present invention. In FIG. 1, parts that are the same as or correspond to those in FIG. 26 are given the same reference numerals and description thereof is omitted. In the figure, 30 is the rotational speed N detected by the finger speed generator and the speed command N from the speed command device 14.
_A programmable controller that outputs a speed command N _C for control to the speed control amplifier 7 based on A
It is provided with D converters 34 and 41, a DA converter 43, and a CPU, that is, an arithmetic unit (acceleration monitoring circuit) 31.

The calculation unit 31 operates the tilt speed command N _E via the speed increasing speed command circuit 35 and the digital speed command N _A 'via the AD converter 41, which is activated when the base rotation speed N _R is detected. Is incorporated, and an automatic deceleration circuit (not shown) and the like are incorporated, and the digital speed command N is added based on the addition output of the data addition unit 55.
And a driving control circuit 56 for outputting a _C '.

The speed-up component speed command circuit (speed-up component speed command output circuit) 35 compares the output of the speed-up component speed command tilt signal generator 32 with the rotation speed N which is the output of the AD converter 34. A comparison / correction circuit (acceleration monitoring circuit) 33 for correcting the output of the speed-up component speed command inclination signal generator 32 is provided.
The comparison and correction circuit 33 stores in advance the relationship for converting the increased speed tilt speed command into the speed command N _C of the electric motor 1.

Next, the operation of this embodiment will be described. First, when the range not reaching the maximum notch of the speed commander 14 is selected, the programmable controller 30
The speed command N _A input to is input to the speed control amplifier 7 as it is as the speed command N _C via the AD converter 41, the operation control circuit 56, and the DA converter 43. Therefore,
The rotation speed N of the electric motor 1 is controlled according to the speed command N _A output from the speed command unit 14. At this time, since the armature voltage Ea is equal to or lower than the rated voltage command E _R , the field thyristor 13 controls the maximum value priority circuit 25 to keep the field current Ib constant.

On the other hand, when the maximum notch of the speed commander 14 is selected, the speed command N _A corresponding to the base rotation speed N _R is input to the programmable controller 30, and the electric motor 1 is accelerated to the base rotation speed N _R as described above. To do. Electric motor 1
When the rotation speed N of the rotation speed reaches the base rotation speed N _R , the speed-up component speed command circuit 35 outputs the speed-up component as a tilt speed command N _E which is a tilt signal. At this time, the tilt speed command N _E is compared with the rotation speed N detected by the finger speed generator 10. If the rotation speed N follows the tilt speed command N _E , the tilt speed command is further increased, Speed up to high speed is possible. Also,
If the rotational speed N is to follow the inclination speed command N _E, it reduces the tilt speed command N _E. As a result, speed control can be performed with the minimum necessary torque according to the load amount.

FIG. 2 is a flowchart showing the operation of the programmable controller 30 when the maximum notch is selected, and the speed control when the maximum notch is selected will be described below based on this flowchart. According to this flowchart, first, it is judged whether or not the rotation speed N of the electric motor 1 detected by the finger speed generator 10 is equal to or higher than the base rotation speed N _R (step ST1), and the rotation speed N is set to the base rotation speed N. _{When R} is reached, a predetermined tilt speed command N _E is output, and the speed reference corresponding to the speed increase is shifted in the direction of increasing speed (step ST2). At this time, the tilt speed command N _E for the increased speed and the speed command N _A from the speed command unit 14 are added, and the speed reference obtained as a result is output as the control speed command N _C (step ST
3).

Further, whether or not the current rotation speed N exceeds the value N _C ″, with the value 0.5 seconds before the speed command N _C (this value is stored) being N _C ″. Is judged (step ST4), and when it is judged to be over,
The speed command N _C in the step ST3 is stored (step ST5), the process returns to the step ST1, and it is judged that the rotational speed N does not exceed the value N _C ″ 0.5 seconds before in the process of the step ST1 and thereafter. As a result, the tilt speed command N _E for the increased speed may be increased to the maximum speed However, in step ST4, the rotation speed N is set to the value N _C ″ 0.5 seconds before. If it is determined that the speed has not exceeded, the rotational speed N does not follow the speed command N _C , so the value N _C ″, which is the immediately preceding comparison establishment data, is output as the tilt speed command N _E for increased speed. (Step S
T6). Therefore, the torque according to the speed command N _C ″ at this time is the minimum required torque according to the load, and the motor 1
The torque generated at is stable at the optimum value according to the load.

The 0.5 used in step ST4
The reference of the second is not limited to this, and may be any time as long as it can be determined whether or not the rotation speed N of the electric motor 1 follows the speed command N _C.

Example 2. The configuration of the electric motor speed control device of the second embodiment is similar to that of the electric motor speed control device of the first embodiment shown in FIG. 1, but the operation of the comparison correction circuit 33 is different. That is, in the first embodiment, since it is determined whether the current rotation speed exceeds the speed reference 0.5 seconds before, it is determined whether the rotation speed N follows the speed command. The speed reference is dropped after confirming that the speed reference does not exist, and there is a case where the speed reference once increases and then decreases, resulting in a case where the transition from acceleration to constant speed is not smoothly performed. In the second embodiment, the transition from acceleration to constant speed is smoothly performed by suppressing the drop.

FIG. 3 is a flow chart showing the operation of the programmable controller of the second embodiment. In FIG. 3, the same processing steps as those in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, step ST
At 11, it is determined whether the change amount of the rotation speed N exceeds 95% of the change amount of the speed command N _C which is the speed reference,
Based on this determination result, it is determined whether or not the rotation speed N follows the speed command, and when it does not follow, the speed command N _C "of the comparison establishment data immediately before (0.5 seconds before) is output. .

As a result, the transition from the acceleration to the constant speed is smoothly performed, and the phenomenon such as the shake of the load can be prevented.

The 95 used in step ST11
The standard of% is preferably 100%, but may be another value in consideration of an error.

Example 3. In this embodiment, since the load during hoisting and the time during hoisting are not changed in the state in which the load is suspended, the speed that is the speed reference determined during hoisting when the speed commander has the maximum notch. The command N _C (inclination speed command N _E for acceleration and the speed command N _A 'from the speed commander 14) is stored, and the rotation speed becomes higher than the base rotation speed at the maximum notch of the speed commander at the time of lowering. Then, the rotation speed of the electric motor is controlled based on the stored speed reference.

FIG. 3 is a flow chart showing the operation of the programmable controller 30 of this embodiment at the time of hoisting, and step ST12 is based on the speed reference determined at the time of hoisting when the speed commander 10 has the maximum notch. This is a storage processing step. FIG. 4 is a flow chart showing the operation at the time of lowering, and step ST21 and step ST22 are processing steps showing that the speed reference stored in step ST12 is used.

When the speed command unit 14 is not the maximum notch, the rotation speed of the electric motor is controlled on the basis of the speed based on the speed command given from the speed command unit.

In this embodiment, the circuit or process for determining the speed command value at the time of lowering when the speed commander 14 has the maximum notch is simplified.

Embodiment 4 FIG. FIG. 5 is a functional block diagram showing the configuration of the electric motor speed control device of the fourth embodiment. Figure 5
In FIG. 1, the same or corresponding parts as in FIG. In the figure, reference numeral 61 denotes an emergency stop signal generation circuit (base rotation speed monitoring means), and when the speed commander 14 is not set to the maximum notch and the rotation speed of the electric motor 1 becomes equal to or higher than the base rotation speed N _R , an emergency stop is performed. A signal is output to stop the electric motor 1 in an emergency.

FIG. 6 is a flow chart showing the operation of the emergency stop signal generation circuit 61. The rotation speed N of the electric motor 1 is equal to or higher than the base rotation speed N _R if the speed commander 14 is set to the maximum notch. However, it is abnormal that the rotation speed N of the electric motor 1 exceeds the base rotation speed N _R even though the maximum notch is not set, and it can be assumed that the electric motor is in a runaway state. The generation circuit 61 outputs an emergency stop signal, which causes the electric motor 1
Emergency stop. In addition, this emergency stop of the electric motor 1
This can be realized by shutting off the power source of the electric motor speed control device by the emergency stop signal and also shutting off the power source of the electromagnetic brake (not shown) to mechanically restrain the rotation of the electric motor.

In this embodiment, the emergency stop signal is output when the rotation speed N of the electric motor 1 exceeds the base rotation speed N _R while the speed commander 14 is not set to the maximum notch. However, instead of the base rotation speed N _R , another rotation speed may be used.

Example 5. FIG. 7 is a functional block diagram showing the configuration of the electric motor speed control device of the fifth embodiment. Figure 7
In FIG. 1, the same or corresponding parts as in FIG. In the figure, reference numeral 62 denotes an emergency stop signal generating circuit (control speed monitoring means), which sets the speed command N _C and its speed when the speed command is set by the speed command device 14 to control the rotation speed of the electric motor 1. The current rotation speed N with respect to the rotation speed N ′ before a predetermined time, which is predicted from the rotation speed N controlled by the command N _C , is
By determining whether or not the state predicted in the normal state is reached, it is detected that the rotational speed of the electric motor has fallen into an uncontrollable state.

FIG. 8 is a flow chart showing the operation of the emergency stop signal generating circuit 62 at the time of hoisting and lowering of the crane when this electric motor speed control device is used for a crane electric motor, and the speed command device 14 operates it. Speed command N
_{When C} is output (step ST31), the rotation speed N of the electric motor 1 is controlled so as to follow the speed command (step ST32). At this time, the rotation speed N is the speed command N _C
It is judged whether or not it is following within the range of ± 5% (step ST33), and when it is following within the range of ± 5%, it is judged to be normal. On the other hand, when it is out of the range of ± 5%, at the next step ST34, the rotation speed N
Determines whether it is trying to follow the speed command N _C from the plus direction or from the minus direction.

As a result, when it is judged that the vehicle is trying to follow from the minus direction (N <N _C ),
Since it is assumed that the rotation speed N is controlled to increase in comparison with the rotation speed N ′ of a predetermined time (0.5 seconds before in this case), the rotation speed N is higher than the rotation speed N ′. It is judged whether it is in a large state (step ST3
5) If it is in the assumed state, it is normal, and if it is not in the assumed state, the rotation speed N of the electric motor 1 is not normally controlled, and an emergency stop is performed.

When it is determined in step ST34 that the vehicle is trying to follow from the plus direction (N> N _C ), the rotation speed N is the rotation speed of a predetermined time before (0.5 seconds before in this case). Since it is assumed that the control should be performed in the direction of decreasing compared with N ', the rotation speed N
Is smaller than the rotation speed N '(step ST35), and if it is in the assumed state, it is normal. If not, the rotation speed N of the electric motor 1 is determined. Is in an emergency stop because it is not in a normal control state.

In this embodiment, in step ST33, it is determined whether or not the rotation speed N follows within ± 5% of the speed command N _C , but the range is not limited to this range. Absent. Further, in step ST35 or step ST36, the current rotation speed N is set to 0.5.
Although the rotation speed N ′ before the second is compared, it is not limited to this time.

Example 6. FIG. 9 is a functional block diagram showing the configuration of the electric motor speed control device of the sixth embodiment. Figure 9
In FIG. 1, the same or corresponding parts as in FIG. In the figure, reference numeral 63 is an emergency stop signal generating circuit (control direction monitoring means), and when the speed command is set to zero by the speed command device 14 to control the rotation speed of the electric motor 1, the current rotation speed N becomes zero. By determining whether or not the motor is being controlled, it is detected that the rotational speed of the electric motor is in an uncontrollable state.

FIG. 10 is a flow chart showing the operation of the emergency stop signal generation circuit 63 when the speed command device 14 is set to the zero notch when this electric motor speed control device is used for a crane electric motor.

Example 7. FIG. 11 is a functional block diagram showing the configuration of the electric motor speed control device of the seventh embodiment. 11, parts that are the same as or equivalent to those in FIG. 1 are assigned the same reference numerals and explanations thereof are omitted. In the figure, 49 is an AD converter that converts the armature voltage Ea output from the voltage sensor 8 into a digital armature voltage, 64 is an emergency stop signal generation circuit (armature voltage monitoring means), and the speed commander 1
4, when the speed command is set to zero and the rotation speed of the electric motor 1 is controlled, it is determined whether or not the current armature voltage Ea is controlled toward zero, so that the rotation speed of the electric motor cannot be controlled. It detects that you are falling into a different state.

FIG. 12 is a flow chart showing the operation of the emergency stop signal generating circuit 64 when the speed command device 14 is set to the zero notch when the electric motor speed control device is used for a crane electric motor.

In this embodiment, when the speed commander 14 has a notch of zero, it is judged whether or not the digital armature voltage output from the AD converter 49 is changing to the direction of zero, and the value is zero. If it has not changed in the direction of, the motor is stopped as an emergency as an abnormality, so that the runaway state of the motor can be detected based on the armature voltage, and safety can be secured.

Example 8. FIG. 13 is a functional block diagram showing the configuration of the electric motor speed control device of the eighth embodiment. 13, parts that are the same as or correspond to those in FIG. 1 are assigned the same reference numerals and explanations thereof are omitted. In the figure, reference numeral 65 denotes an emergency stop signal generating circuit (armature current polarity monitoring means), which sets the speed command device to the operation state immediately before the speed command device 14 set the speed command to zero and the speed command device to zero. The fact that the electric motor is in an uncontrollable state is detected from the polarity of the armature current Ia at that time.

FIG. 14 is a flow chart showing the operation of the emergency stop signal generation circuit 65 when the speed command device 14 is set to the zero notch when this electric motor speed control device is used for a crane electric motor. FIG. 15 is a characteristic diagram showing changes in the speed command N _C , the armature voltage Ea, the armature current Ia, the rotation speed N, and the field current Ib at the time of hoisting and lowering. The armature current Ia becomes negative when this is done, and the armature current Ia becomes positive when the lowering operation is made into a zero notch.
Based on the polarity of the armature current Ia, it can be determined whether or not the electric motor is normally controlled. The armature current Ia and the torque have a proportional relationship.

Example 9. FIG. 16 is a functional block diagram showing the configuration of the electric motor speed control device of the ninth embodiment. 16, parts that are the same as or equivalent to those in FIG. 1 are assigned the same reference numerals and explanations thereof are omitted. In the figure, 66 is an emergency stop signal generation circuit (armature current value monitoring means), 66a
Is a timer provided in the emergency stop signal generation circuit 66, and when the motor is controlled according to a non-zero speed command set by the speed command device 14, the armature current Ia is kept for a predetermined time (0.5 seconds). ), A value close to zero (0 ± 20 A)
It is detected whether or not the electric motor is in an uncontrollable state by determining whether or not is maintained. The predetermined time is set by the timer 56a.

FIG. 17 is a flowchart showing the operation of the emergency stop signal generation circuit 66 when a non-zero speed command is set by the speed command device 14 when the motor speed control device is used for a crane motor.

The predetermined time is not limited to 0.5 seconds, and is not limited to 0 ± 20 A if the armature current has a value close to zero.

Example 10. FIG. 18 is a functional block diagram showing the configuration of the electric motor speed control device of the tenth embodiment. 18, parts that are the same as or equivalent to those in FIG. 1 are assigned the same reference numerals and explanations thereof are omitted. In the figure, 6
Reference numeral 7 denotes an emergency stop signal generation circuit (operation monitoring means) for setting the speed command by the speed command device 14 for a predetermined time (1
By determining whether or not it has been performed a predetermined number of times (3 times) within a second, it is detected that the electric motor is in an uncontrollable state. That is, when the electric motor becomes uncontrollable, the driver desperately operates the speed commander 14 to control the uncontrollable electric motor, so that the speed commander 14 operates in this state. Judge by the number of times.

FIG. 19 is a flow chart showing the operation of the emergency stop signal generation circuit 67 which detects the number of times the speed commander 14 is operated when the electric motor speed control device is used for a crane electric motor and makes an emergency stop.

The predetermined time is not limited to 1 second, and the number of speed command setting operations by the speed command device 14 is not limited to 3 times.

Example 11. FIG. 20 is a functional block diagram showing the configuration of the electric motor speed control device of the eleventh embodiment. 20, parts that are the same as or correspond to those in FIG. 1 are assigned the same reference numerals and explanations thereof are omitted. In the figure, 6
Reference numeral 8 denotes an emergency stop signal generation circuit (speed feedback monitoring means), which determines whether or not the rotation speed N of the electric motor 1 has become zero after a predetermined time (2 seconds) when the speed commander 14 is set to a zero notch. It is detected that the electric motor is in an uncontrollable state.

FIG. 21 shows an emergency stop signal generation circuit 68 when this electric motor speed control device is used for a crane electric motor.
3 is a flowchart showing the operation of FIG.

The time elapsed from when the speed commander 14 is set to the zero notch is not limited to 2 seconds.

Example 12 FIG. 22 is a functional block diagram showing the configuration of the electric motor speed control device according to the twelfth embodiment. 22, parts that are the same as or correspond to those in FIG. 1 are assigned the same reference numerals and explanations thereof are omitted. In the figure, 6
Reference numeral 9 denotes an emergency stop signal generation circuit (speed change amount monitoring means). Is the change amount of the rotation speed N of the electric motor 1 equal to or more than a predetermined amount (1 m / s ² ) when the speed command device 14 is set to the zero notch. It is detected that the electric motor is in an uncontrollable state.

FIG. 23 shows an emergency stop signal generating circuit 69 when this electric motor speed control device is used for a crane electric motor.
3 is a flowchart showing the operation of FIG.

The amount of change in the rotation speed N of the electric motor 1 for detecting that the electric motor is in an uncontrollable state, 1
Since m / s ² depends on the capability of the motor speed control device, it is not limited to the above value.

Example 13 FIG. 24 is a functional block diagram showing the configuration of the electric motor speed control device of the thirteenth embodiment. In FIG. 24, portions that are the same as or correspond to those in FIG. In the figure, 7
Reference numeral 0 denotes an emergency stop signal generation circuit (armature voltage change amount monitoring means), and the change amount of the armature voltage Ea of the motor 1 is a predetermined amount (10 v / s when the speed command device 14 is set to a zero notch).
² ) Detecting that the motor is in an uncontrollable state by determining whether or not it is above.

FIG. 25 shows an emergency stop signal generating circuit 70 when this motor speed control device is used for a crane motor.
3 is a flowchart showing the operation of FIG.

The change amount of the armature voltage Ea of the electric motor 1 for detecting that the electric motor is in an uncontrollable state, 10 v / s ² is influenced by the capacity of the electric motor speed control device. The value is not limited.

In the embodiments described above, the motor speed control device of each embodiment is applied to the combination of the DC motor and the thyristor Leonard, but the torque components in the AC motor and the vector control inverter are described. It is also possible to apply to current and field component current,
Has the same effect.

[0091]

As described above, according to the first aspect of the invention, the AD converter for converting the speed feedback into the digital speed feedback, and the speed increase for monitoring the state of the speed increase of the electric motor by the speed feedback. A speed increase / minute speed command output circuit that outputs a speed increase / minute speed command output circuit that outputs a speed increase / minute speed command according to the monitoring result of the speed increase / speed monitoring circuit, and the speed increase / minute speed command output circuit outputs the speed increase / minute speed command. Since it is configured with a programmable controller that outputs a speed command for control based on the addition of the command and the speed command generated by the speed commander, it is necessary for the load depending on the state of increasing the rotation speed of the electric motor. There is an effect that an electric motor speed control device capable of controlling an electric motor by generating a minimum torque is obtained.

According to the second aspect of the present invention, since the speed increasing monitoring circuit for monitoring the amount of change in the rotation speed of the electric motor is provided in the process of weakening the field, it is possible to increase the rotation speed of the electric motor. Depending on the state, it is possible to control the amount of field weakening with respect to the load without performing constant speed operation at the base speed, and to obtain the minimum required torque for the load to control the electric motor. is there.

According to the third aspect of the invention, since the speed reference for controlling the crane hoisting is used as the speed reference for controlling the crane lowering, the programmable controller for controlling the electric motor is provided. , A motor speed control device capable of controlling the field weakening amount against a load without performing constant speed operation at the base speed with a simple configuration and generating a minimum required torque for the load to control the motor effective.

According to the fourth aspect of the present invention, when the efficiency control is not being executed, it is configured to include a base rotation speed monitoring means for monitoring that the rotation speed is lower than the base rotation speed and outputting an emergency stop signal of the electric motor. Therefore, there is an effect that a motor speed control device capable of preventing runaway of the motor and ensuring safety can be obtained.

According to the fifth aspect of the present invention, the speed feedback trace data is compared with the speed command data of the speed command device, and it is monitored whether or not the current rotation speed is a controlled speed. Since the control speed monitoring means for outputting the emergency stop signal is provided, it is possible to obtain an electric motor speed control device capable of preventing runaway of the electric motor and ensuring safety.

According to the sixth aspect of the present invention, when the speed commander has a zero notch during operation of the electric motor, it is monitored whether the direction of control of the rotational speed of the electric motor by the digital speed feedback is toward zero. However, since the control direction monitoring means for outputting the emergency stop signal of the electric motor is provided, it is possible to obtain an electric motor speed control device capable of preventing runaway of the electric motor and ensuring safety.

According to the invention of claim 7, an AD converter for converting the armature voltage feedback in the speed feedback into a digital armature voltage feedback, and a zero notch for the speed commander during the operation of the electric motor. , Monitoring whether the armature voltage is going toward zero,
Since the armature voltage monitoring means for outputting the emergency stop signal of the electric motor is provided, it is possible to obtain the effect of the electric motor speed control device capable of preventing the runaway of the electric motor and ensuring the safety based on the change of the armature voltage. is there.

According to the invention of claim 8, when the speed commander is set to the zero notch during the winding operation of the electric motor, the armature current controlled by the armature current feedback is controlled to a negative current value. Also, when the speed commander has a zero notch during the lowering operation, it is monitored that the armature current controlled by the armature current feedback is controlled to a current value in the positive direction, Since the armature current polarity monitoring means for outputting the emergency stop signal of the electric motor is provided, it is possible to obtain the effect of providing the electric motor speed control device capable of preventing the runaway of the electric motor and ensuring safety based on the change of the armature current. is there.

According to the ninth aspect of the present invention, it is monitored whether or not the armature current during the operation of the electric motor is continuously maintained near zero, and the armature current value monitoring for outputting the emergency stop signal of the electric motor is monitored. Since it is configured to include the means, it is possible to obtain an electric motor speed control device capable of preventing runaway of the electric motor and ensuring safety based on the armature current value near zero.

According to the tenth aspect of the present invention, the number of times of hoisting operation and / or hoisting operation with respect to the speed command device during operation of the electric motor for the crane is monitored,
Since the operation monitoring means for outputting the emergency stop signal of the electric motor is provided, the abnormality of the electric motor is judged based on the operation state of the operator with respect to the speed command device, the electric motor is stopped by the emergency stop signal, and the electric motor runs out of control. There is an effect that a motor speed control device that can prevent the above and can ensure safety is obtained.

According to the eleventh aspect of the present invention, it is monitored whether or not the armature voltage or the armature current controlled by the speed feedback becomes zero after a predetermined time has elapsed since the speed commander was set to the zero notch. However, since the speed feedback monitoring means for outputting the emergency stop signal of the electric motor is provided, the electric motor based on the armature voltage or the armature current after a predetermined time has elapsed from the time when the speed commander has the zero notch. There is an effect that a motor speed control device capable of preventing runaway and ensuring safety can be obtained.

According to the twelfth aspect of the present invention, when the speed commander is set to the zero notch during operation of the electric motor, the amount of change in the speed being controlled toward zero by digital speed feedback is monitored, Since the speed change amount monitoring means for outputting the emergency stop signal of the electric motor is provided, the runaway of the electric motor is prevented based on the amount of change in the rotation speed of the electric motor when the speed commander is set to the zero notch, and the safety is improved. There is an effect that a secure motor speed control device can be obtained.

According to the thirteenth aspect of the present invention, when the speed commander is set to the zero notch during operation of the electric motor, the amount of change in the armature voltage which is controlled toward zero by the digital armature voltage feedback. Is configured to include an armature voltage change amount monitoring unit that outputs an emergency stop signal of the electric motor, so that the motor based on the amount of change in the armature voltage of the electric motor when the speed commander has a notch There is an effect that a motor speed control device capable of preventing runaway and ensuring safety can be obtained.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of an electric motor speed control device according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the programmable controller when the maximum notch is selected in the motor speed control device according to the first embodiment.

FIG. 3 is a flowchart showing the operation of a programmable controller of the motor speed control device according to the second and third embodiments of the present invention.

FIG. 4 is a flowchart showing an operation at the time of lowering the programmable controller of the electric motor speed control device according to the third embodiment of the present invention.

FIG. 5 is a functional block diagram showing the configuration of an electric motor speed control device according to a fourth embodiment of the present invention.

FIG. 6 is a flowchart showing the operation of an emergency stop signal generation circuit of the electric motor speed control device according to the fourth embodiment.

FIG. 7 is a functional block diagram showing the configuration of an electric motor speed control device according to a fifth embodiment of the present invention.

FIG. 8 is a flowchart showing an operation of an emergency stop signal generation circuit of the electric motor speed control device according to the fifth embodiment.

FIG. 9 is a functional block diagram showing the configuration of an electric motor speed control device according to a sixth embodiment of the present invention.

FIG. 10 is a flowchart showing the operation of an emergency stop signal generation circuit of the electric motor speed control device according to the sixth embodiment.

FIG. 11 is a functional block diagram showing the configuration of an electric motor speed control device according to a seventh embodiment of the present invention.

FIG. 12 is a flowchart showing an operation of an emergency stop signal generation circuit of the electric motor speed control device according to the seventh embodiment.

FIG. 13 is a functional block diagram showing the configuration of an electric motor speed control device according to an eighth embodiment of the present invention.

FIG. 14 is a flowchart showing the operation of the emergency stop signal generation circuit of the electric motor speed control device according to the eighth embodiment.

FIG. 15 is a speed command at the time of hoisting and lowering the electric motor, which is controlled by the electric motor speed control device according to the eighth embodiment.
It is a characteristic view which shows change of armature voltage, armature current, rotation speed, and field current.

FIG. 16 is a functional block diagram showing the configuration of an electric motor speed control device according to a ninth embodiment of the present invention.

FIG. 17 is a flowchart showing the operation of the emergency stop signal generation circuit of the electric motor speed control device according to the ninth embodiment.

FIG. 18 is a functional block diagram showing the structure of an electric motor speed control device according to a tenth embodiment of the present invention.

FIG. 19 is a flowchart showing the operation of the emergency stop signal generation circuit of the electric motor speed control device according to the tenth embodiment.

FIG. 20 is a functional block diagram showing the configuration of an electric motor speed control device according to an eleventh embodiment of the present invention.

FIG. 21 is a flowchart showing the operation of the emergency stop signal generation circuit of the electric motor speed control device according to the eleventh embodiment.

FIG. 22 is a functional block diagram showing the structure of an electric motor speed control device according to a twelfth embodiment of the present invention.

FIG. 23 is a flowchart showing the operation of the emergency stop signal generation circuit of the electric motor speed control device according to the twelfth embodiment.

FIG. 24 is a functional block diagram showing the configuration of an electric motor speed control device according to a thirteenth embodiment of the present invention.

FIG. 25 is a flowchart showing the operation of the emergency stop signal generation circuit of the electric motor speed control device according to the thirteenth embodiment.

FIG. 26 is a functional block diagram showing a configuration of a conventional electric motor speed control device.

FIG. 27 is a characteristic diagram showing torque-speed characteristics of an electric motor.

[Explanation of symbols]

1 electric motor, 7 speed control amplifier (speed feedback control system), 14 speed commander, 20 automatic field controller (field control system), 30 programmable controller,
33 comparative correction circuit (acceleration monitoring circuit), 34 AD converter, 35 acceleration speed command circuit (acceleration speed command output circuit), 61 emergency stop signal generation circuit (base rotation speed monitoring means), 62 emergency stop Signal generation circuit (control speed monitoring means), 63 emergency stop signal generation circuit (control direction monitoring means), 64 emergency stop signal generation circuit (armature voltage monitoring means), 65 emergency stop signal generation circuit (armature current polarity monitoring means) ), 66 emergency stop signal generation circuit (armature current value monitoring means), 67 emergency stop signal generation circuit (operation monitoring means), 68 emergency stop signal generation circuit (speed feedback monitoring means), 69 emergency stop signal generation circuit (speed) Change amount monitoring means), 70 emergency stop signal generation circuit (armature voltage change amount monitoring means), N rotation speed, N _A speed command, N
Speed command for _C control, N _E speed-up component speed command, Ea
Armature voltage, Ia armature current, Ib field current.

Claims (13)

[Claims] 1. A speed commander for generating a speed command of an electric motor, and a speed feedback control for controlling an armature voltage of the electric motor according to a deviation between a speed command generated by the speed commander and a rotation speed of the electric motor. A system, a field control system that compares the armature voltage with a field current of the electric motor, and controls the field current so that the armature voltage does not exceed a rated voltage, and a speed feedback of the electric motor. A programmable controller that outputs a speed command for control according to the load of the electric motor to the speed feedback control system based on the above, and the programmable controller includes an AD converter that converts the speed feedback into a digital speed feedback. An acceleration monitor circuit for monitoring the state of acceleration of the rotation speed of the electric motor by the speed feedback; A speed-up component speed command output circuit that outputs a speed-up component speed command according to the monitoring result of the speed-up monitoring circuit, and the speed-up component speed command output by the speed-up component speed command output circuit and the speed. An electric motor speed control device which outputs the speed command for control based on addition with a speed command generated by a command device. 2. The motor speed control device according to claim 1, wherein the speed-up monitoring circuit monitors the amount of change in the rotation speed of the motor in the process of weakening the field. 3. The electric motor is an electric motor for a crane, and the programmable controller stores a speed reference signal for control when hoisting the crane, and outputs the stored speed reference signal when hoisting the crane. The electric motor speed controller according to claim 1. 4. The programmable controller comprises base rotation speed monitoring means for monitoring that the rotation speed is lower than or equal to the base rotation speed when not in efficiency control, and outputting an emergency stop signal according to the monitoring result. The electric motor speed control device according to any one of claims 1 to 3, wherein: 5. The programmable controller compares the trace data of the speed feedback with the speed command data of the speed command device to monitor whether or not the current rotation speed is a controlled speed, 4. The motor speed control device according to claim 1, further comprising a control speed monitoring unit that outputs an emergency stop signal according to a monitoring result. 6. The programmable controller monitors whether the direction of control of the rotation speed of the electric motor by the digital speed feedback is toward zero when the speed commander has a zero notch during operation of the electric motor. The motor speed control device according to any one of claims 1 to 3, further comprising control direction monitoring means for outputting an emergency stop signal according to the monitoring result. 7. The programmable controller converts the armature voltage feedback in the speed feedback into a digital armature voltage feedback A
When the D converter and the speed commander are set to a notch during operation of the electric motor, it is monitored whether the armature voltage is in the direction of zero, and an emergency stop signal is output according to the monitoring result. The motor speed control device according to any one of claims 1 to 3, further comprising an armature voltage monitoring means. 8. The motor is a motor for a crane, and the programmable controller includes an AD converter for converting armature current feedback in the speed feedback into digital armature current feedback, and the programmable controller during the hoisting operation of the motor. When the speed commander has a zero notch, it is monitored that the armature current controlled by the armature current feedback is controlled to a current value in the negative direction, and the speed commander is set to zero during the lowering operation. When notched, the armature current polarity controlled by the armature current feedback is monitored to control that the current value in the positive direction is controlled, and an emergency stop signal is output according to the monitoring result. An electric motor according to any one of claims 1 to 3, further comprising means. Machine speed control device. 9. The armature that monitors whether or not the armature current during operation of the electric motor continuously maintains a value near zero, and outputs an emergency stop signal according to the monitoring result. The electric motor speed control device according to claim 1, further comprising a current value monitoring means. 10. The electric motor is an electric motor for a crane, and during operation of the electric motor, both or one or both of a hoisting operation and a hoisting operation based on a hoisting command and / or a hoisting command by the speed commander. 4. The electric motor speed control device according to claim 1, further comprising: an operation monitoring unit that monitors the number of times of operations and outputs an emergency stop signal according to the monitoring result. 11. The programmable controller comprises:
It monitors whether the armature voltage or the armature current controlled by the speed feedback becomes zero after a predetermined time has elapsed from the time when the speed commander has a zero notch, and an emergency response is made according to the monitoring result. 4. The motor speed control device according to claim 1, further comprising speed feedback monitoring means for outputting a stop signal. 12. When the speed commander has a zero notch during operation of the electric motor, the amount of change in speed at which control is performed toward zero by the digital speed feedback is monitored, and the monitoring result is displayed. 7. The electric motor speed control device according to claim 6, further comprising speed change amount monitoring means for outputting an emergency stop signal accordingly. 13. When the speed commander has a zero notch during operation of the electric motor, the amount of change in the armature voltage being controlled toward zero by the digital armature voltage feedback is monitored, 8. The motor speed control device according to claim 7, further comprising armature voltage change amount monitoring means for outputting an emergency stop signal according to the monitoring result.