JPS60229683A - Overload inverter - Google Patents

Abstract

PURPOSE:To automatically eliminate a malfunction phenomenon by temporarily reversely rotating a motor when an excess load is applied to the motor, and the returning the motor to the normal rotation. CONSTITUTION:When a switch 12 is closed, a normal rotation signal is output from an AND circuit 10, and a normal direction current is flowed to a motor 5. At this time, if the state that a motor current detected by a current detecting resistor 2 is the prescribed value or higher continues for the prescribed time or longer, a comparator 8 outputs a signal. Thus, a reverse rotation signal is output from an AND circuit 11, and a reverse current is flowed to the motor 5. When the prescribed time is then elapsed, a normal rotation signal is again output from the AND circuit 10. Thus, a defect can be automatically removed to continue the normal operation.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an overload reversing device that temporarily reverses the load to remove the problem when the overload occurs.

If a disturbance is applied to the operating part of a device that is rotating in the forward direction to prevent its rotation, conventionally the windings of the motor used would generate heat, so a thermostat was attached to the windings. The difference in thermal expansion caused by the heat generation caused the circuit to open and rotation to stop, and the problem was then removed manually.

That is, conventionally, the countermeasure for removing such obstacles has been to manually rotate the rotating parts in the opposite direction.

However, manual handling of the apparatus as described above was not easy and took a lot of time.

The present invention has been made in view of the above-mentioned difficulties and to solve the problems, and provides an overload reversing device that automatically removes the obstacle and maintains normal operation when an excessive load is applied to the motor. The purpose is to

Next, a detailed explanation will be given with reference to the drawings. In FIG.
is provided in series with the rotor 5 of the DC magnet field motor, and its output is input to the comparator 4. The setting of the excessive current judgment level is based on the variable resistor 3ζζ.

6 is an overcurrent time detection section, which includes a capacitor 7 and a comparison N8.
The output of comparator 4 is input to comparator 8 via capacitor 7. 9 is a timing circuit, which is a timer T1;
It consists of T2, T3 and an AND circuit 10.11, and the output of the comparator 8 is input to a timer T and T2, and each timer T, T2 and T3 is triggered at the falling edge. 12
is the motor switch. Reference numeral 13 denotes a forward/reverse switching circuit, and since a normal one is used, its explanation will be omitted.

Next, the operation of the overload reversing device of the present invention will be described. When the switch 12 of the remoter is turned on manually or by other means to start the motor, the timing chart shown in FIG. 2 occurs. That is, when the load applied to the motor is not excessive, the voltage level of the output of the comparator 4 is high, and therefore the output of the AND circuit, that is, the motor forward rotation signal, is high level, and the output of the AND circuit 11, that is, the motor reverse rotation signal, is high level. The signal will be at a low level.

When the load on the motor exceeds the excessive current judgment level,
The output of the comparator 4 becomes a low voltage level, the capacitor 7 is discharged, and the output of the AND circuit 10, that is, the motor forward rotation signal, temporarily becomes a low voltage level, and the output of the AND circuit 11, that is, the motor reverse rotation signal, becomes a low voltage level. High voltage level.

As described above, the overload reversing device of the present invention temporarily reverses the motor when an excessive load is applied to the motor, and then returns the motor to normal rotation. Therefore, it is possible to automatically eliminate any abnormal phenomenon that occurs during the normal operation of the motor by normal rotation, and to continue to perform the normal operation. As described above, according to the present invention, the intended purpose can be achieved.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a circuit diagram showing an embodiment of the circuit of the present invention, and FIG. 2 is a timing chart. 1... Overcurrent detection section 2... Current detection resistor 5...
・DC motor rotor

Claims (1)

[Claims] A current detection resistor is provided in series with the rotor winding of the DC magnet field motor, and the output of this current detection resistor is compared with a set voltage level, and when the output exceeds the set voltage level for a predetermined time, The overload reversing device is characterized in that the voltage level of the forward rotation signal of the motor becomes one state, and then the voltage level of the reverse rotation signal of the motor becomes another state, and the rotation of the motor is reversed.