JPH05161375A - Operating state detector for motor - Google Patents

Abstract

PURPOSE:To detect immediately a failure, such as a stoppage of a rotary part even when a motor is rotated. CONSTITUTION:An operating state detector includes a speed detector 9 for detecting speeds at rotating parts 2 and 3, a first operating state confirming circuit 11 for generating a rotating part working signal 13 or a rotating part stop signal 14 in accordance with a detected signal 12 of ON or OFF, each provided by the speed detector 9. Moreover, the operating state detector includes motor load current detector 17, a second operating state confirming circuit 18 for generating a normal load signal 21 when a load current signal 19 from the motor load current detector 17 exceeds a preset current 20 that is preset slightly over a no-load current of a motor 1, and an abnormal load signal 22 when the load current signal 19 doesn't exceed the preset current 20, and an operating state detecting circuit 26 for generating a rotating machine driving signal 24 or a rotating machine stop signal 25 in accordance with signals from the first and second operating state confirming circuits 11 and 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation detecting device for electric equipment in various plant facilities.

[0002]

2. Description of the Related Art For example, in a cement plant facility, the manufacturing process is a consistent flow process from raw material loading to product shipment, and most of the drive devices are occupied by electric motors. Excluding the driving electric motors such as mills, kilns, and various fans from the cement plant equipment, most of them are electric motors of transportation systems such as conveyors and bucket elevators that connect the devices to each other.

Therefore, when a failure occurs in a part of the transport system composed of a large number of electric motors, the flow work is confused, it takes time to restore the work, and productivity is significantly impaired. For this reason, all cement plant equipment employs control based on a general control system. That is, each transport aircraft is electrically interlocked, and the upstream side automatically stops from the failed device.At the time of start-up and stop, start-up and stop are performed in the order determined according to the interlock schedule. It is supposed to be. Specifically, each device is automatically started in accordance with a start / stop schedule set for each group of transportation system in each equipment unit. In addition, when the vehicle is stopped, the next start can be smoothly performed by discharging the raw materials or the products on the transporting machine according to a predetermined time limit according to a schedule opposite to the start, and then sequentially stopping.

In such cement plant equipment,
In order to increase the reliability of the important general control system, when establishing the interlock schedule, a speed detector is installed to check the operating status of each device (whether each device is rotating reliably). is doing.

Conventionally, in establishing an interlock schedule, as a method of detecting whether or not each device is operating reliably, it is generally determined that the motor is in an operating state when the electromagnetic contactor for the motor is turned on. Is done by doing.

However, this system is premised on that the electric motor is inevitably in an operating state when the electromagnetic contactor for the electric motor is turned on. Even if a trouble such as a cable breakage occurred, it could not be detected, and it was insufficient considering the influence on the plant.

Therefore, in recent cement plants and the like, in addition to the electromagnetic contactor for electric motor being turned on, it is performed to detect whether or not the device is actually operating (rotating). There is. As the detection method, a protrusion is attached to a part of the rotating body, the protrusion is detected in a non-contact manner, and a proximity switch for extracting a pulse signal, or a speed detector such as a pulse generator (rotation detector) Has been adopted.

[0008]

However, there is a problem even when the above-mentioned electromagnetic contactor for an electric motor is turned on and, in addition to that, a conventional system using a detection signal of a speed detector such as a proximity switch or a pulse generator. Was occurring. That is, the speed detector is not a problem if it is a conveyor, a bucket elevator, or the like whose operating state can be visually observed as it is, but a fan, a blower, etc. is normal as long as the equipment is viewed from the outside (external However, due to breakage of the rotary drive shaft or damage to the shaft connecting part, there is a problem that the rotating part of the rotating device is not rotating even though the electric motor is operating. Was there. The electrical signal is normal once it occurs, so that the operation of the plant is continued, which has a great influence on the plant, which is a serious problem that leads to the stop of the plant.

The present invention has been made in view of the above-mentioned problems of the related art, and the operation of an electric device capable of immediately detecting an accident in which the electric motor is rotating and the rotating portion is not operating. An object is to provide a detection device.

[0010]

According to the present invention, a speed detector for detecting the speed of a rotating part rotated by an electric motor, and a rotating part actuating signal is output by a detection signal ON of the speed detector,
A first operation confirmation circuit that outputs a rotation part stop signal when the detection signal of the speed detector is OFF, a motor load current value detector, and a load current signal from the motor load current value detector is a no-load current value of the motor. From the second operation confirmation circuit that outputs a load normal signal when it exceeds a set current value that is set slightly larger, and a load abnormal signal when it does not reach the set current value, and from the first operation confirmation circuit. When the rotating part operation signal and the load normal signal from the second operation confirmation circuit are input, the rotating device start signal is output, and the rotating part stop signal from the first operation confirmation circuit and the second operation confirmation circuit An operation detection device for an electric device, comprising: an operation detection circuit that outputs a rotation device stop signal when any of the load abnormality signals is input.

[0011]

[Operation] When the detection signal of the speed detector is ON, the first operation confirmation circuit outputs the rotation section operation signal, and when the detection signal of the speed detector is OFF, the first operation confirmation circuit stops the rotation section. Output a signal. Also, when the load current signal from the motor load current value detector exceeds the set current value that is set slightly higher than the no-load current value of the motor, the second operation confirmation circuit outputs the load normal signal, When the current signal does not reach the set current value, the second operation confirmation circuit outputs a load abnormality signal. When the rotating part operation signal from the first operation confirmation circuit and the load normal signal from the second operation confirmation circuit are input, the operation detection circuit outputs a rotating device activation signal, and the first operation confirmation circuit When either of the rotating part stop signal and the load abnormality signal from the second operation confirmation circuit are input, the operation detection circuit outputs the rotating device stop signal. This allows
It is possible to immediately detect an accident in which the electric motor is rotating and the rotating part is not operating, and it is possible to improve the reliability of control of the electric device.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example in which the operation detecting device of the present invention is applied to a blower (electrical device). The blower includes an electric motor 1, a rotary drive shaft (rotating portion) 2, and the rotary drive shaft. Impeller (rotating part) 3 fixed to 2 and impeller 3
And a casing 6 that surrounds the air and introduces the air taken in from the air intake 4 to the impeller 3, and draws out the air compressed by the impeller 3 from the air outlet 5.
The drive power supply 7 for the electric motor 1 is provided with an electromagnetic contactor 8 for starting and stopping the electric motor 1.

A speed detector 9 is provided on the rotary drive shaft 2 of the blower. The speed detector 9 may be a proximity switch or a pulse generator that detects the projection 10 provided on a part of the rotary drive shaft 2 in a non-contact manner and extracts a pulse signal. The speed detector 9 is connected to the first operation confirmation circuit 11, and the first operation confirmation circuit 1
The reference numeral 1 outputs a rotating portion operation signal 13 when the detection signal 12 of the speed detector 9 is ON, outputs a rotating portion stop signal 14 when the detection signal 12 is OFF, and further, a driving signal 15 of the electromagnetic contactor 8. Is ON and the detection signal 12 of the speed detector 9 is O
The alarm signal 16 is output at the time of FF.

Further, the drive power source 7 of the electric motor 1 is provided with an electric motor load current value detector 17, and a second operation confirmation circuit 18 is connected to the electric motor load current value detector 17. The second operation confirmation circuit 18 outputs a load normal signal 21 when the load current signal 19 from the motor load current value detector 17 exceeds a set current value 20 which is set slightly higher than the no-load current value of the motor 1. Output the above set current value 2
The load abnormal signal 22 is output when the load current is less than 0, and the alarm signal 23 is output when the drive signal 15 of the electromagnetic contactor 8 is ON and the no-load current signal 19 is less than the set current value 20. There is. The set current value 20 is, for example, a value obtained by multiplying the no-load current value of the electric motor 1 by 1.05, and when the electric motor load current value is less than or equal to the set current value 20, it can be surely determined to be abnormal. ing. The increase of 5% at this time is the power required to drive the rotary drive shaft 2 directly connected to the electric motor 1,
Therefore, for this increase, an optimum value is appropriately selected according to the weight of the shaft and the like.

Further, when both the rotating portion operation signal 13 from the first operation confirming circuit 11 and the load normal signal 21 from the second operation confirming circuit 18 are input, the rotating equipment starting signal 2
4 is output, and when either the rotation stop signal 14 from the first operation check circuit 11 or the load abnormality signal 22 from the second operation check circuit 18 is input, a rotation device stop signal 25 is output. A circuit 26 is provided.

When the detection signal 12 of the speed detector 9 is ON, the first operation confirmation circuit 11 outputs the rotating part operation signal 13, and when the detection signal 12 of the speed detector 9 is OFF, the first operation is performed. The confirmation circuit 11 outputs a rotating portion stop signal 14. The load current signal 19 from the motor load current value detector 17
Is set to a setting current value 20 which is set to be slightly larger than the no-load current value of the motor 1, that is, 1.05 to the no-load current value of the motor 1.
When it exceeds the value multiplied by, the second operation confirmation circuit 18
Outputs a load normal signal 21, and when the load current signal 19 is less than the set current value 20, the second operation confirmation circuit 18 outputs a load abnormality signal 22. Rotating part operation signal 13 from the first operation confirmation circuit 11 and second operation confirmation circuit 1
When both of the load normal signals 21 from 8 are input, the operation detection circuit 26 outputs the rotating device start signal 24, and the rotation part stop signal 14 from the first operation check circuit 11 and the second operation check circuit. When any of the load abnormality signals 22 from 18 is input, the operation detection circuit 26 outputs the rotating device stop signal 25.

In the speed detector 9 described above, the electromagnetic contactor 8 is used.
By the ON / OFF operation of, the rotation of the rotating parts 2 and 3 can be immediately detected via the first operation confirmation circuit 11.

Further, the second operation confirmation circuit 18 connected to the motor load current value detector 17 has a set current value 2 of the motor 1.
0 is set to a value obtained by multiplying the no-load current value of the electric motor 1 by 1.05 in consideration of the power required to drive the rotary drive shaft 2 directly connected to the electric motor 1. Axis 2
It is possible to immediately detect an abnormality and output the rotating device stop signal 25 when the rotating parts 2 and 3 are not operating (no load state) due to breakage of the shaft or damage to the shaft connecting part. Further, the set current value 20 can be easily obtained by adopting the value at the time of inspection at the manufacturing factory of the electric motor 1, and can be highly reliable, and further, the device adjustment period at the site. Can be shortened.

Therefore, in addition to the operation of the electromagnetic contactor 8, by adopting an operation detecting device combining the outputs of the speed detector 9 and the motor load current value detector 17, it is possible to confirm the operation of the fans and blowers. And the reliability of the overall control system for the plant as a whole can be improved,
It can contribute to safe and stable operation of the plant.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the scope of the present invention.

[0022]

According to the above-described operation detecting apparatus for an electric device of the present invention, the rotation of the rotating portion is detected by the speed detector,
Since the motor load current detector detects the load condition of the motor and enables immediate detection of an accident in which the motor is rotating and the rotating part is not operating, the operation of the rotating equipment can be confirmed reliably. The reliability of the overall control system for the entire plant can be improved, and an excellent effect that can contribute to safety and stable operation of the plant can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 electric motor 2 rotation drive shaft (rotating part) 3 impeller (rotating part) 9 speed detector 11 first operation confirmation circuit 12 detection signal 13 rotating part operating signal 14 rotating part stop signal 17 electric motor load current value detector 18 second Operation check circuit 19 Load current signal 20 Set current value 21 Load normal signal 22 Load abnormal signal 24 Rotating equipment start signal 25 Rotating equipment stop signal 26 Operation detection circuit

Claims (1)

[Claims] 1. A speed detector for detecting the speed of a rotating part rotated by an electric motor, and a rotating part operation signal is output when a detection signal of the speed detector is turned on, and a detection signal OF of the speed detector is detected.
A first operation confirmation circuit that outputs a rotation part stop signal by F, a motor load current value detector, and a load current signal from the motor load current value detector are set to be slightly larger than the no-load current value of the motor. A second operation confirmation circuit that outputs a load normal signal when the set current value is exceeded, and outputs a load abnormal signal when the set current value is not satisfied, and a rotating part operation signal from the first operation confirmation circuit. When the load normal signal from the second operation confirmation circuit is input, the rotating equipment start signal is output, and either the rotating part stop signal from the first operation confirmation circuit or the load abnormality signal from the second operation confirmation circuit is output. And an operation detection circuit that outputs a rotation device stop signal when the input signal is input.