JPH11113162A - Monitor and control device of dc motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sense abnormalities in the appliance and the circuit of a DC motor not only during its driving but also before its starting, by sensing through a current sensing means the current in the power supply circuit in the state of not started, and by comparing the sensed current value with a preset current value. SOLUTION: Connecting a resistor 14 in parallel with a contact 10 of a starter switch and providing a main-circuit-current sensor 15 for sensing the current of a power supply circuit, a current (a) sensed by the main-circuit-current sensor 15 is inputted to an abnormality sensing means 16. Then, comparing with a preset current value 17 the current in the power supply circuit in the state of a DC motor 1 being not started, an abnormal signal (b) is outputted from the abnormality sensing means 16 to an alarm circuit 13 when the sensed current (a) is smaller than the preset current value 17. Therefore, since the current of the power supply circuit is reduced when the abnormalities of disconnection, etc., are generated in the respective windings inside the DC motor 1 and in a cable 7, disconnection of the power supply can be sensed by the abnormality sensing means 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct-current motor main body and a monitoring and control device for the direct-current motor for detecting an abnormality of its circuit.

[0002]

2. Description of the Related Art FIG. 11 is an example of a circuit diagram of a conventional monitoring and control device for a DC motor. The DC motor 1 is composed of an armature winding 2, an auxiliary pole winding 3, a series winding 4, and a shunt winding 5. The DC motor 1 is a control center for supplying power to the motor (monitoring control device). 6 and a cable 7. The control center 6 supplies power to the DC motor 1 from a DC power supply via a circuit breaker 8, an overload relay 9, a contact 10 of a starting switch, and a starting current suppressing resistor 11. Further, power is supplied to the shunt winding 5 directly after passing through the overload relay 9. The starting current suppressing resistor 11 has an intermediate tap, and the contacts 10-1 and 10-2 of the starting switch are connected so as to short-circuit the starting current suppressing resistor 11 when the contacts are closed. Contacts 10, 10-
1 and 10-2 are controlled by the control circuit 12. Here, the method at the time of starting will be described. First, the circuit breaker 8 is closed and then the contact 10 of the starting switch is closed. At this time, a current flows through the DC motor 1 via the starting current suppressing resistance value 11 to start the starting, and immediately thereafter, the contact 10-1 is closed,
Thereafter, the contact 10-2 is closed and the starting current suppressing resistor 11 is closed.
Is bypassed, the entire voltage is applied to the DC motor 1, and the startup is completed, and the operation is performed. In the event of a short-circuit accident, the circuit breaker 8 is opened by an overcurrent tripping function in the circuit breaker 8 and an alarm signal is output to the alarm circuit 13 in the event of a short-circuit accident. When the motor is overloaded, an overload relay 9 issues an alarm signal to the alarm circuit 13.

[0003]

In general, DC motors are often used as emergency motors in in-flight equipment such as industrial equipment and power plants. For example, lubricating oil supply pumps such as generators and turbines in power plants are usually used. Uses an emergency oil pump that is provided as an emergency because the AC motor is used and if this AC motor breaks down or the AC power supply is cut off, the oil supply cannot be stopped. doing. Therefore, in spite of the fact that a DC motor is an important thing that must always be started in an emergency in many cases, as described above, the protection and monitoring of a DC motor is only for detecting an accident or abnormality during operation and issuing an alarm. There is a problem that the abnormality of the DC motor before starting is not detected, and the reliability of the circuit is lacking in checking the soundness of the circuit. SUMMARY OF THE INVENTION It is an object of the present invention to provide a DC motor monitoring and control device capable of detecting abnormalities in devices and circuits not only during operation of the DC motor but also before startup.

[0004]

According to a first aspect of the present invention, there is provided a monitoring and control device for a DC motor having a power supply circuit having a contact of a start switch for supplying power to the DC motor. Current detecting means for detecting a current flowing in the power supply circuit as an impedance element connected in parallel with the contact of the power supply, and a current setting for presetting a current flowing in the power supply circuit when the DC motor is not started And a current value detected by the current detection means, and an abnormality detection means for detecting an abnormality when the current value detected by the current detection means is smaller than the current set value. If there is a disconnection, the current flowing in the power supply circuit is detected by the current detecting means,
This current value becomes smaller than the current set value, and the abnormality of the circuit can be detected.

[0005] In the second aspect of the present invention, the first aspect is provided.
Instead of the abnormality detection means described, by the abnormality detection means for detecting an abnormality when the current value detected by the current detection means is larger than the current set value when the DC motor is not started, If a short circuit occurs in the circuit when the DC motor is not started, the current flowing in the power supply circuit increases, and the current value detected by the current detecting means becomes larger than the current set value, so that abnormality of the circuit can be detected.

According to a third aspect of the present invention, in a power supply circuit having a contact of a starting switch for supplying power to a DC motor, an impedance element connected in parallel with a contact of the starting switch; Voltage detecting means for detecting the voltage between both ends of the DC motor, a voltage set value for presetting the voltage between both ends of the impedance element when the DC motor is not started, and comparing the voltage value detected by the voltage detecting means, Abnormality detecting means for detecting an abnormality when a voltage value detected by the voltage detecting means is smaller than the voltage setting value, and when there is a disconnection of a circuit or a power failure, a current flowing in a power supply circuit decreases and the voltage detecting means As a result, the detected voltage value becomes smaller than the voltage set value, and the abnormality of the circuit can be detected.

[0007] In the invention of claim 4, the above-mentioned claim 3
Instead of the abnormality detection means described, by the abnormality detection means to detect an abnormality when the voltage value detected by the voltage detection means is larger than the voltage set value when the DC motor is not started, If a short circuit occurs in the circuit when the DC motor is not started, the current flowing in the power supply circuit increases, and the voltage value detected by the voltage detecting means becomes larger than the voltage set value, so that abnormality of the circuit can be detected.

In a power supply circuit having a contact of a starting switch for supplying power to a DC motor, the relay connected in parallel with the contact of the starting switch and the DC motor are started. When the DC motor is not activated, if there is a disconnection in the circuit or the power supply is cut off, the relay becomes inoperative and an abnormality can be detected.

According to a sixth aspect of the present invention, there is provided a power supply circuit for a DC motor, comprising: a contact of a starting switch for supplying power to the DC motor; and a circuit for supplying power to a shunt winding of the DC motor. Current detecting means for detecting a current flowing in the shunt winding circuit, and a current set value which presets a current flowing in the shunt winding circuit in a state where the DC motor is not started, and detection by the current detecting means. Abnormality detection means for comparing the current value with the detected current value and detecting an abnormality when the current value detected by the current detection means is smaller than the current set value, and detecting the disconnection of the shunt circuit by the current detection means. The detected current becomes smaller than the current set value, and an abnormality in the circuit can be detected.

Further, by combining the abnormality detecting means according to the first to sixth aspects of the present invention, it is possible to widen an abnormality detection range such as a short circuit or disconnection of the circuit, and to detect an abnormality of the armature main circuit. An abnormality in the shunt winding circuit can also be identified.

[0011]

FIG. 1 is a block diagram of a DC motor monitoring and control apparatus according to a first embodiment of the present invention. A resistor 14 is connected in parallel with the contact 10 of the starting switch, and includes a main circuit current detector 15 for detecting a current of the power supply circuit. The detected current a detected by the main circuit current detector 15 is an abnormality detecting means. 16 and the current flowing in the power supply circuit when the DC motor is not started is compared with a preset current set value 17. If the value is also smaller, the abnormality detection means 16 outputs an abnormality signal b to the alarm circuit 13. Next, a normal operation will be described. Before the DC motor 1 starts, the current flows through the resistor 14. However, by selecting the value of the resistor 14 to a value large enough not to rotate the motor, the current before the start can be measured and detected. By setting this value as the value of the current setting value 17, the current setting value 17 and the detection current a become the same, and the abnormality detection means 16 does not output the abnormality signal b. Here, when an abnormality such as a disconnection occurs in each of the windings and the cable 7 inside the DC motor 1, the current of the power supply circuit decreases, so that the detection current a also decreases and the abnormality detection means 16 outputs the abnormality signal b. . Further, even when the power supply is turned off, the current stops flowing, so that the abnormality detection means 16 can detect the power-off abnormality.

Therefore, according to the present embodiment, the disconnection abnormality and the power supply abnormality of the entire circuit can always be detected before or after the start. FIG. 2 is a configuration diagram of a DC motor abnormality monitoring device according to a second embodiment of the present invention.

FIG. 2 is different from FIG.
3 is shown in detail in FIG. In FIG. 3, when the contact 10 of the starting switch shown in FIG. 2 is open, the abnormality detecting means 16 receives an open state signal c of the starting switch from the control circuit 12 and is detected by the main circuit current detector 15. When the detected current a is larger than the current set value 17 by the comparison circuit 18 that compares the detected current a with the value of the current set value 17, the signal is output to the AND circuit 19, and A
The ND circuit 19 includes an open state signal c of the start switch and a detection current a.
Is larger than the value of the current set value 17 with the signal.
An abnormal signal b is output to the alarm circuit 13 when the condition D is satisfied.

Next, a normal operation will be described. Before the DC motor 1 starts, the current flows through the resistor 14. However, by selecting the value of the resistor 14 to a value large enough not to rotate the motor, the current before the start can be measured and detected. By setting this value as the value of the current setting value 17, the current setting value 17 and the detection current a become the same, and no signal is output from the comparison circuit 19 to the AND circuit 19. Therefore, there is no abnormal signal b which is the output of the AND circuit 19. After the start, the contact 10 of the start switch is closed, and a large current flows through the circuit.
At this time, since the open state signal c of the starting switch is not input to the AND circuit 19, no abnormal signal b is output.

Here, if an abnormality such as a short circuit occurs in each of the windings and the cable 7 inside the DC motor 1 before the motor is started, the current of the power supply circuit increases. Is output to the AND circuit 19, and before the start, the contact 10 of the start switch is open, so that the condition of the AND circuit 19 is satisfied and the abnormality signal b is output to the alarm circuit 13.

Therefore, according to the present embodiment, it is possible to detect a short circuit abnormality of the circuit before starting. FIG. 4 is a configuration diagram of a DC motor abnormality monitoring device according to a third embodiment of the present invention.

In FIG. 4, a resistor 14 is connected in parallel with the contact 10 of the starting switch. The voltage d across the resistor 14 is input to the abnormality detecting means 20, and the resistor 14 is supplied when the DC motor is not started. Is compared with a preset voltage setting value 21. If the value of the both-ends voltage d is smaller than the voltage setting value 21, the abnormality detection means 20 outputs an abnormality signal b to the alarm circuit. 13 is output.

Next, the normal operation will be described. Before the DC motor 1 is started, a current flows through the resistor 14. However, the voltage d across the resistor 14 before the start is measured by selecting the value of the resistor 14 to a value large enough not to rotate the motor. Can be detected, and by setting this value as the value of the voltage set value 21, the current set value 21 and the resistance 1 can be detected.
4, the voltage d between both ends becomes the same, and the abnormality detection means 20 does not output the abnormality signal b. Here, if an abnormality such as a disconnection occurs in each of the windings and the cable 7 inside the DC motor 1, the current of the power supply circuit decreases. Is output. In addition, even when the power supply is turned off, the current stops flowing, so that the abnormality detection means 20 can detect the power-off abnormality.

Therefore, according to the present embodiment, it is possible to always detect the disconnection abnormality of the circuit and the abnormality of the power supply disconnection regardless of before or after the start. FIG. 5 is a configuration diagram of a DC motor abnormality monitoring device according to a fourth embodiment of the present invention.

FIG. 5 is different from FIG.
FIG. 6 shows the details. In FIG. 6, when the contact 10 of the starting switch shown in FIG. 5 is open, the abnormality detecting means 20 receives the open state signal c of the starting switch from the control circuit 12 and outputs the voltage d across the resistor 14 and the voltage set value. When the voltage d across the resistor 14 is larger than the voltage set value 21 by the comparison circuit 22 that compares the value of the signal 21, the signal is output to the AND circuit 19, and the AND circuit 19 outputs the open state signal of the start switch. An abnormal signal b is output to the alarm circuit 13 when an AND condition between the signal c and the signal d when the voltage d across the resistor 14 is larger than the voltage set value 21 is satisfied.

Next, the normal operation will be described. Before the DC motor 1 starts, the current flows through the resistor 14. However, by selecting the value of the resistor 14 to a value large enough not to rotate the motor, the current before the start can be measured and detected. By setting this value as the voltage setting value 21, the voltage setting value 22 and the voltage d across the resistor 14 become the same, and no signal is output from the comparison circuit 22 to the AND circuit 19. Therefore, there is no abnormal signal b which is the output of the AND circuit 19. After the start, the contact 10 of the start switch is closed, and a large current flows through the circuit.
A signal is output to the D circuit 19, but at this time, the open state signal c of the starting switch is not input to the AND circuit 19, so that no abnormal signal b is output.

Here, if an abnormality such as a short circuit occurs in each of the windings and the cable 7 inside the DC motor 1 before starting the motor, the current of the power supply circuit increases. 22 is the AND circuit 1
9 before the start, and since the contact 10 of the start switch is open, the condition of the AND circuit 19 is satisfied and the abnormal signal b is output to the alarm circuit 13.

Therefore, according to the present embodiment, it is possible to detect a short circuit abnormality of the circuit before starting. FIG. 7 is a configuration diagram of a DC motor abnormality monitoring device according to a fifth embodiment of the present invention.

In FIG. 7, a relay 23 is connected in parallel with the contact 10 of the starting switch. The contact 24 of the relay 23 is inputted to the abnormality detecting means 25. When the open state signal c of the relay is input and the DC motor is not started, the relay 23
Is detected, and an abnormality signal b is output from the abnormality detection means 25 to the alarm circuit 13.

FIG. 8 is a diagram showing the details of the abnormality detecting means 25. In FIG. 8, when the contact 10 of the starting switch shown in FIG. The open state signal c and the operation signal of the contact 24 of the relay 23 are input to the AND circuit 19, and the AND circuit 19 outputs the A of the open state signal c of the start switch and the operation signal of the contact 24.
An abnormal signal b is output to the alarm circuit 13 when the ND condition is satisfied.
Next, a normal operation will be described. Before the start of the DC motor 1, the contact 10 of the start switch is open,
By setting the resistance value of 3 to a value large enough to prevent the motor from rotating, most of the power supply voltage is applied to the relay 23, and the relay 23 operates. Here, the contact 24 opens when the relay 23 is operating, and the relay 2
In the above case, since the relay 23 is operating, the contact 24 is open, and the signal from the contact 24 is not input to the AND circuit 19, so that the AND circuit 3 There is no abnormal signal b which is an output. Here, if an abnormality such as a disconnection occurs in each of the windings and the cable 7 inside the DC motor 1, the current in the power supply circuit disappears, and no voltage is applied to the relay 23, so that the relay 23 does not operate and the contact 24 closes. . When the contact 24 is closed, a signal from the contact 24 is input to the AND circuit 19, and the AND circuit 19 outputs an abnormal signal b to the alarm circuit 13 when an AND condition with the open state signal c of the start switch is satisfied. I do. In addition, even when the power supply is cut off, the current stops flowing similarly, so that the relay 23 becomes inactive.
The signal is output to 3 and a power-off abnormality can be detected.

Therefore, according to the present embodiment, it is possible to always detect the disconnection abnormality of the circuit and the power supply abnormality regardless of before or after the start. FIG. 9 is a configuration diagram of a DC motor abnormality monitoring device according to a sixth embodiment of the present invention.

In FIG. 9, a shunt circuit current detector 26 for detecting a current flowing in a shunt winding circuit of the DC motor 1 is provided, and a detection current e detected by the shunt circuit current detector 26 is used as an abnormality detecting means 27. The abnormality detection means 27 compares the value of the detection current e with the value of a preset current value 28, which is a preset value of the current flowing in the shunt winding circuit of the DC motor 1, and determines the value of the detection current a. If the value is smaller than the set value 28, an abnormal signal b is output to the alarm circuit 13.

Next, a normal operation will be described. In a normal state, a constant current flows through the shunt circuit of the DC motor 1. By setting this value as the current setting value 28, the current setting value 28 and the detection current e are the same. No abnormal signal b is output. Here, if an abnormality such as disconnection occurs in the shunt winding of the DC motor 1 and the cable 7, the current disappears, so that the detection current e becomes zero and the abnormality detection means 27 outputs the abnormality signal b. Further, even when the power supply is cut off, the current stops flowing, so that the abnormality detection means 27 can detect the power cut-off abnormality.

Therefore, according to the present embodiment, disconnection abnormality and power supply abnormality of the shunt circuit can be always detected regardless of before or after startup. FIG. 10 is a configuration diagram of a DC motor abnormality monitoring device according to a seventh embodiment of the present invention.

FIG. 10 is a block diagram of an abnormality monitoring device in which the abnormality detecting means 20 shown in FIG. 4 and the abnormality detecting means 27 shown in FIG. 9 are combined. As described above, each winding and cable 7 inside the DC motor 1 When an abnormality such as a disconnection occurs, the current of the power supply circuit decreases, so that the voltage d across the resistor 14 also decreases, and the abnormality detection unit 20 outputs the abnormality signal b. In addition, even when the power supply is turned off, the current stops flowing, so that the abnormality detection means 20 can detect the power-off abnormality. Further, if an abnormality such as disconnection occurs in the shunt winding of the DC motor 1, the current disappears, so that the detection current e becomes zero and the abnormality detection means 27 outputs the abnormality signal b.

Therefore, according to the present embodiment, the abnormality detection range of the circuit can be widened, and the abnormality of the armature main circuit and the abnormality of the shunt circuit can be distinguished. In addition, by combining with the abnormality detecting means 20 shown in FIG. 5, it is possible to detect an abnormality at the time of short circuit of the circuit, and it is also possible to identify the abnormality of the short circuit and the disconnection.

[0032]

According to the present invention, the detection of disconnection of the circuit and the detection of disconnection of the power supply before the start of the DC motor can be easily realized, and a short circuit accident of the circuit during operation can be detected. A monitoring and control device for a DC motor can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a DC motor abnormality monitoring device according to a first embodiment of the present invention;

FIG. 2 is a configuration diagram of a DC motor abnormality monitoring device according to a second embodiment of the present invention;

FIG. 3 is a detailed view of the abnormality detecting means shown in FIG. 2;

FIG. 4 is a configuration diagram of a DC motor abnormality monitoring device according to a third embodiment of the present invention.

FIG. 5 is a configuration diagram of a DC motor abnormality monitoring device according to a fourth embodiment of the present invention.

FIG. 6 is a detailed view of the abnormality detecting means shown in FIG. 5;

FIG. 7 is a configuration diagram of a DC motor abnormality monitoring device according to a fifth embodiment of the present invention.

FIG. 8 is a detailed view of the abnormality detecting means shown in FIG. 7;

FIG. 9 is a configuration diagram of a DC motor abnormality monitoring device according to a sixth embodiment of the present invention.

FIG. 10 is a configuration diagram of a DC motor abnormality monitoring device according to a seventh embodiment of the present invention.

FIG. 11 is a diagram showing an example of a circuit diagram of a conventional DC motor.

[Explanation of symbols]

1 DC motor, 2 armature winding, 3 auxiliary winding, 4
DC winding, 5 winding winding, 6 control center,
7 ... Cable, 8 ... Circuit breaker, 9 ... Overload relay, 10 ...
Reference numerals 10-1, 10-2: contacts of a starting switch, 11: starting current suppressing resistor, 12: control circuit, 13: alarm circuit, 14
... Resistance, 15 ... Main circuit current detector, 16, 20, 25,
27: abnormality detection means, 17, 28: current set value, 18,
Reference numeral 22: comparison circuit, 19: AND circuit, 21: voltage set value, 23: relay, 24: contact of relay, 26: shunt circuit current detector, a, e: detected current, b: abnormal signal, c:
Opening signal of start switch, d ... Voltage across resistor

Claims (6)

[Claims] 1. A monitoring and control device for a DC motor having a power supply circuit having a contact of a starting switch for supplying power to the DC motor, comprising: an impedance element connected in parallel with a main contact of the starting switch; Current detection means for detecting a current flowing in the power supply circuit; a current setting value for presetting a current flowing in the power supply circuit when the DC motor is not started; and a current value detected by the current detection means And a fault detecting means for detecting a fault when the current value detected by the current detecting means is smaller than the current set value. 2. An abnormality is detected when the current value detected by the current detection means is larger than the current set value when the DC motor is not started, instead of the abnormality detection means according to claim 1. 2. The monitoring and control device for a DC motor according to claim 1, wherein the abnormality detection means performs an abnormality. 3. A monitoring and control device for a DC motor having a power supply circuit having a contact of a start switch for supplying power to the DC motor, wherein the impedance element is connected in parallel with the contact of the start switch. Voltage detecting means for detecting the voltage across the impedance element, and comparing the voltage value detected by the voltage detecting means with the current set value which presets the voltage across the impedance element when the DC motor is not started. A monitoring and control device for a DC motor, comprising: abnormality detection means for detecting an abnormality when a voltage value detected by the voltage detection means is smaller than the voltage set value when the DC motor is not started. . 4. An abnormality is detected when the voltage value detected by the voltage detection unit is larger than the voltage set value when the DC motor is not started, instead of the abnormality detection unit according to claim 3. A monitoring and control device for a DC motor, wherein the monitoring and control device is an abnormality detecting means. 5. A monitoring and control device for a DC motor having a power supply circuit provided with a contact of a starting switch for supplying power to the DC motor, comprising: a relay connected in parallel with the contact of the starting switch; A monitoring and control device for a DC motor, comprising an abnormality detecting means for detecting a malfunction of the relay when the relay is not started. 6. A current flowing through a shunt winding circuit in a power supply circuit including a contact of a start switch for supplying power to a DC motor and a circuit for supplying power to a shunt winding of the DC motor. Current detection means for detecting the current, a current set value which presets a current flowing in the shunt winding circuit when the DC motor is not started, a current value detected by the current detection means, and the current setting A monitoring and control device for a DC motor, comprising: abnormality detection means for comparing values and detecting an abnormality when a current value detected by the current detection means is smaller than the current set value.