JPH07231560A - Motor controller - Google Patents

Abstract

PURPOSE:To notify the abnormal state by delivering an alarm to the outside if a motor does not enter into operating state due to insufficient contact of main contacts in an electromagnetic contactor or insufficient connection of the main circuit upon receiving an operation command to a motor controller. CONSTITUTION:If the current value of a main circuit 1, detected by a current detection circuit 11a, does not vary when a signal for driving an electromagnetic contactor 4 to operate a motor 2 is delivered to a drive circuit 11c, the logic operation circuit 11d in a control circuit 11 makes a decision that the electromagnetic contactor 4 or the main circuit 1 is connected insufficiently. It is notified on a display circuit 11e, and a fault output relay 11f is driven to deliver an alarm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device for controlling the opening and closing of a main circuit of an induction motor, and further monitoring the main circuit current to open the main circuit by an electromagnetic contactor when an abnormality is detected. In particular, the present invention relates to a motor control device having a function of issuing an alarm to the outside when a failure of an electromagnetic contactor is detected.

[0002]

2. Description of the Related Art An electric motor control device of this type is an electromagnetic contactor for controlling the opening and closing of a load in a main circuit between a power bus and an induction motor (hereinafter referred to as an electric motor), and an overload current protection for the electric motor. A main circuit device such as a current transformer and a circuit breaker for wiring is interposed, and a start operation switch and a stop operation switch for controlling the start and stop of the electric motor by opening and closing the electromagnetic contactor are provided. Is configured.

Further, this type of motor control device detects an overload current of the motor and a ground fault current of the main circuit. When an abnormality is detected, the failure state is displayed on the display circuit and the failure state is output to the outside by a relay contact. It has a function to do.

[0004]

However, since the conventional motor control device does not have a function of detecting a contact failure of the main circuit contact of the electromagnetic contactor, a defective state due to welding, or a connection failure of the main circuit, the electromagnetic contact is not achieved. When the electric motor control device is given an operation command for the electric motor in a state in which the electric motor is out of order, not only the electric motor does not enter the operating state, but also the failure state cannot be known to the outside.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electric motor with a main contact failure of an electromagnetic contactor or a main circuit connection failure when an operation command of the electric motor is given to the electric motor control device. When the operating state is not entered, an alarm is displayed outside, and a contact signal can be sent to the outside to notify the outside that the main circuit is in an abnormal state. To provide.

[0006]

According to the present invention, there is provided an electromagnetic contactor for controlling start and stop of an electric motor by opening and closing a main circuit of the electric motor, a drive circuit for driving the electromagnetic contactor, and A current detection circuit connected to the circuit that detects the signal from the current transformer that detects the main circuit current, a display circuit that displays the state of the motor, and a fault output relay that notifies the state to the outside when a fault occurs. And a logic operation circuit for controlling the drive circuit and the display circuit and processing the current from the current detection circuit, the logic operation circuit is a drive circuit for driving the electromagnetic contactor. If there is no change in the value of the main circuit current detected by the current detection circuit when the drive signal is sent, the display circuit will indicate that the electromagnetic contactor or the main circuit has a bad connection, and a failure will occur. Characterized by being configured to output an alarm to the outside by driving the relay.

[0007]

When a motor control command is given to the motor control device, if the main circuit is in a normal state, a specific current flows through the motor. However, even if the motor drive command is given, the main contact failure of the electromagnetic contactor occurs. When the current does not flow to the motor due to poor connection of the main circuit, the current detection circuit can detect an abnormality because there is no change in the current value, so this can be displayed externally and output to the outside by the fault output relay. It will be possible.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. Reference numeral 1 denotes a main circuit that supplies power to the electric motor 2. The main circuit 1 includes a circuit breaker 3 for wiring, an electromagnetic contactor 4, a current transformer 5 for detecting the main circuit current, and a zero-phase current of the main circuit. A device such as a zero-phase current transformer 6 for detecting is interposed.

The primary side of the operating transformer 7 is connected between the load phase of the circuit breaker 3 for wiring and the power phase side of the electromagnetic contactor 4. On the secondary side of the operating transformer 7, the coil 4a of the electromagnetic contactor 4, the starting operation switch 9,
The stop operation switch 10 and the control circuit 11 are connected. The control circuit 11 receives the start signal and the stop signal from the start operation switch 9 and the stop operation switch 10, opens and closes the electromagnetic contactor 4, and inputs the current signal from the current transformer 5 and the zero-phase current transformer 6. It also has the function of performing overload protection, open phase protection, ground fault protection, etc. on the load side. In the control circuit 11, a signal from the current detection circuit 11a that detects the main circuit current sent from the current transformer 5 and the zero-phase current transformer 6 and a signal from the current detection circuit 11a are calculated to monitor the abnormality of the main circuit current. With
A logical operation circuit 11d that reads the contact state of the start operation switch 9 and the stop operation switch 10 from the voltage detection circuit 11b and outputs a command to the drive circuit 11c for applying a voltage to the coil 4a for opening and closing the electromagnetic contactor 4. , A display circuit 11e for displaying outside when an abnormality of the main circuit 1 is detected, and a failure output relay 1 for outputting outside
It is composed of 1f.

In such a motor control device, when the start operation switch 9 is pressed, the logical operation circuit 11d
This state is read by the voltage detection circuit 11b, the drive circuit 11c is operated to excite the coil 4a of the electromagnetic contactor 4, and the electromagnetic contactor 4 is closed to bring the electric motor 2 into an operating state.

If the main circuit 1 and the electromagnetic contactor 4 are normal, the current flowing through the electric motor 2 is detected by the logical operation circuit 11c from the current transformer 5 via the current detection circuit 11a. The logical operation circuit 11d outputs a signal for closing the electromagnetic contactor 4 to the drive circuit 11c, but there is no change in the current value flowing through the current transformer 5 detected via the current detection circuit 11a. , It judges that the main circuit 1 or the electromagnetic contactor 4 is out of order, displays an abnormal state on the display circuit 11e, and activates the failure output relay 11f to output it to the outside.

Similarly, with the electric motor 2 in operation,
When the start / stop switch 10 is pressed, the logical operation circuit 11
d reads this state by the voltage detection circuit 11b, stops the drive circuit 11c in order to release the electromagnetic contactor 4, opens the electromagnetic contactor 4, and brings the electric motor 2 into a stopped state. Although the logical operation circuit 11d outputs a signal for opening the electromagnetic contactor 4 to the drive circuit 11c, the current value flowing through the current transformer 5 detected through the current detection circuit 11a does not become "0". In this case, it is determined that the main circuit 1 or the electromagnetic contactor 4 is out of order, an abnormal state is displayed on the display circuit 11e, and the failure output relay 11f is activated and output to the outside.

As described above, according to the above-described embodiment, it is possible to easily detect the failure of the electromagnetic contactor 4 and the connection failure of the main circuit without adding a special circuit, and the display circuit 11e,
Since the fault output relay 11f can output to the outside, the state can be judged from the outside.

[0014]

As described above, according to the electric motor control device of the present invention, the value of the main circuit current detected by the current detection circuit when the drive signal is sent to the drive circuit for driving the electromagnetic contactor is determined. When there is no change, the failure of the electromagnetic contactor is displayed on the display circuit, and the failure output relay is driven to output an alarm to the outside, so the main contact failure of the magnetic contactor or the connection failure of the main circuit. If there is, the state can be judged from the outside and the entire system can be operated efficiently.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a motor control device according to an embodiment of the present invention.

[Explanation of symbols]

1 is a main circuit, 2 is an induction motor, 4 is an electromagnetic contactor, 5 is a current transformer, 6 is a zero-phase current transformer, 7 is an operating transformer, 8 is a control busbar, 9 is a start operation switch, and 10 is Stop operation switch,
11 is a control circuit, 11a is a current detection circuit, 11b is a voltage detection circuit, 11c is a drive circuit, 11d is a logical operation circuit,
Reference numeral 11e indicates a display circuit, and 11f indicates a failure output relay.

Claims (1)

[Claims] 1. An electromagnetic contactor for controlling the start and stop of the induction motor by opening and closing the main circuit of the induction motor, a drive circuit for driving the electromagnetic contactor, and a main circuit connected to the drive circuit. A current detection circuit for detecting a signal from a current transformer for detecting a main circuit current, a display circuit for displaying the state of the induction motor, and a fault output relay for notifying the state to the outside at the time of a fault, In a motor control device comprising a logical operation circuit for controlling the drive circuit and the display circuit and processing the current from the current detection circuit, the logical operation circuit is configured to drive the electromagnetic contactor. When there is no change in the value of the main circuit current detected by the current detection circuit when a drive signal is sent to the drive circuit, it is said that the electromagnetic contactor or the main circuit has a poor connection. An electric motor control device configured to display on a display circuit and drive the fault output relay to output an alarm to the outside.