JPS5915277B2 - Motor operation monitoring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an operation monitoring device for an electric motor, and more particularly, to an operation monitoring device for an electric motor that has a function of inspecting a shingle disconnection device connected to a motor circuit and a function of monitoring the normal operating state of the electric motor. Regarding equipment.

In some cases, several electric motors are connected in parallel to the same power source to perform constant acceleration operation.

When performing such uniform speed acceleration operation, it is necessary to intensively monitor the operating state of each electric motor and promptly detect abnormal rotation of the electric motor. Conventionally, in this type of operation, a voltage and frequency increase pattern is determined in advance and acceleration is performed according to this method. There was a risk that some motors would drop out of constant speed operation due to speed variations. If a motor falls off, it must be detected immediately and removed from the constant speed operation circuit. In addition to monitoring the operating status of these electric motors, it is also necessary to check the functionality of the shear disconnection device, including the sheath disconnector, connected to the motor circuit. This is because if a failure occurs in the motor or main circuit in a constant speed operation circuit, the faulty circuit must be quickly disconnected using a disconnection device, otherwise the accident will spread to other healthy circuits. It is preferable that the monitoring of the operating state of the electric motor and the functional inspection of the sintering device be performed in the same or single operation in a functionally related manner, rather than being performed separately. In view of the above points, an object of the present invention is to obtain a motor operation monitoring device that can effectively monitor the operating state of the electric motor and inspect the shrinking device by the same or a single operation. .

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

In FIG. 1, reference numeral 1 denotes a three-phase AC power source, and a motor 3 is connected to this current 1 via a shear cutter 2. In actual constant speed operation, this power supply 1 is connected to disconnection devices 20, 200, . . .
A large number of electric motors (for example, 100) 30, 30
0... are connected in parallel. The cutoff device 2 includes transistors 4R and 4 connected to the three-phase main circuits R, S, and T, respectively.
Diodes 4DR and 4DS connected in antiparallel with S and 4T
, 4DT, the control circuit 5 and the transistors 4R, 4s
, 4TVC, ON, 0FF control signals are provided. 6R
, 6s, and 6T are current transformers for fault current detection inserted into the RSS and T phase main circuits, and the secondary outputs of the current transformers 6R, 6S, and 6T are rectified by a three-phase full-wave rectifier circuit 7. The control circuit 5
is given as a failure detection signal.

8 is an operation monitoring device that detects the secondary output voltage of the rectifier circuit 7 via a voltage dividing resistor 9 with a voltage detecting device 10, and detects the phase-to-phase voltage between the T phase and S phase of the three-phase main circuit with a detecting resistor 11. The frequency is inputted to the extraction frequency detection device 12 via.

Further, the output signal of the frequency detection device 12 is used to output an 0N-0FF signal to the control circuit 5.
Next, the operation of the motor operation monitoring device having the above configuration will be explained.

0 from the control circuit 5 to each phase transistor 4R, 4s, 4T
When the N signal is applied, the transistors 4R, 4S, and 4T become conductive, and power is supplied from the power source 1 to the electric motor 3 to start and accelerate the motor. When a failure occurs in the main circuit or motor 3, the fault current is detected by current transformers 6R, 6S, and 6T, and control circuit 5
Then, the transistors 4R, 4s, 4TVC0FF signals are applied to disconnect the circuit. Next, in order to inspect the shearing device 2, the current transformer 6R is detected by the voltage detection device 10 of the operation monitoring device 8.
, 6s, 6T If the cable from the power supply to the insulation disconnection device 2 is normal, the voltage detection device 10
The output waveform is a three-phase full-wave rectified waveform as shown in Figure 2 α. If there is an abnormality such as a disconnection in the cable, the output waveform shown in Figure 2 b
As shown in the figure, abnormalities in single-phase full-wave rectified waveforms or cables with distorted waveforms can be detected.

Further, by detecting the waveform of the γ voltage detection device 10, it can be confirmed that the current is flowing normally in the shearing device 2 as well. Furthermore, when the operation monitoring device 8 instantaneously gives an 0FF signal to the control circuit 5 of the shearing device 2, the transistors 4R,
Give the 0FF signal to 4S and 4T to instantly disconnect the main circuit.

A reverse induced voltage is generated between the S and T phases of the disconnected main circuit, which is detected via the detection resistor 11 and is detected by the frequency detection device 12.
・Measure the induced frequency. Based on this frequency, the rotational speed of the electric motor 3 at that time can be determined, so if this rotational speed is within the allowable range, the 0N signal is given to the control circuit 5 again to turn on the transistors 4R, 48, and 4T, and the electric motor 3 is operated. If there is an abnormality in the rotational speed, the transistors 4R, 4s, and 4T are made non-conductive to disconnect the motor 3 from the power supply 1. At the same time, the voltage detection device 10 detects the secondary output voltages of the current transformers 6R, 6S, and 6T, and detects that the detected voltage becomes zero at the same time as the 0FF signal is sent from the operation monitoring device 8 to the control circuit 5. It is possible to check that the shrivel cutting function of the shrivel cutting device 2 is normal. If such monitoring of the operating state of the electric motors 3 and inspection of the sheath cutting device 2 are carried out sequentially for the parallel electric motors, uniform speed operation of multiple electric motors can be ensured.

As described above, according to the present invention, the secondary output of the current transformer that detects the fault current in the main circuit is
Next, if the output is normal, check the condition and continuity of the cable of the shear disconnection device, and instantaneously disconnect the main circuit to detect the induced frequency of the motor and the rotation speed. 2 of the current transformers while monitoring the operating status.
Since the shearing function of the shearing breaker is detected by detecting the next output, monitoring of the operating status of the motor and inspection of the shearing breaker can be performed in the same or in a single operation in relation to each other. operation monitoring equipment can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 A, b
is a waveform diagram showing the secondary output of the current transformer in the present invention. 1...Power supply, 2...Shrinking device, 3...Electric motor,
4R, 4s, 4T...transistor, 5...control circuit, 6R, 6s, 6T...current transformer, 7...rectifier circuit, 8...operation monitoring device.

Claims (1)

[Claims] 1. A function that momentarily disconnects the motor from the main circuit when the motor is in operation, checks the induced frequency of the motor, detects the rotational speed of the motor, and monitors the operating state; A function to check the insulation function of the insulation disconnection device by detecting the secondary output of the current transformer for detecting the fault current of the insulation disconnection device, and a function to check the secondary output of the current transformer for detecting the fault current of the insulation disconnection device. An electric motor operation monitoring device that has the function of checking the conduction status of the shrinking device by detecting the