JPS5915480B2 - Lock detection device for series commutator motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lock detection device that detects when a series commutator motor becomes locked due to an external factor and stops rotating.

In various devices that use series-wound commutator motors as power, any external factor other than a power cut may cause the motor's armature to lock and stop rotating, causing a large current to continue flowing through the motor.3. It is necessary to immediately turn off the power to the motor.

The present invention is a lock detection device characterized in that the lock state can be detected and extracted as a disconnection signal using an extremely simple circuit configuration. The present invention will be explained below using illustrated embodiments.

FIG. 1 is a wiring diagram of a lock detection device according to the present invention. A power supply circuit 1 that supplies current to a motor 2 includes a power supply and a half-wave phase control circuit that limits the current supplied to the motor using a thyristor or the like. is incorporated. A zero rotation detection circuit 3 is connected to both ends of the armature T of the electric motor 2. 8 indicates the life coil of electric motor 2.

When a high load is applied to this motor 2 due to some external factor, the current supplied to the motor 2 is limited by the above-mentioned phase control circuit, the rotation of the motor 2 further decreases, and finally the armature T locks. State and 5 become.

At this time, as shown in the voltage-current waveform diagram of FIG. 3, a negative voltage is applied to the motor at both ends of the armature T due to its self-inductance until the current becomes zero in the negative cycle of the power supply. Furthermore, Fig. 2 shows the waveforms of the voltage E across the armature T and the current I flowing through the armature when the load is light, and Fig. 3 shows the voltage E and current I when the armature T is in the locked state. It shows the waveform of .

In the present invention, the voltage at the part A in FIG. 3, that is, the voltage on the negative side of the power supply voltage, is taken out by interposing the diode 9, and the semiconductor light emitting element, for example, the light emitting diode 10, is caused to emit light.

In this circuit, 11 is a smoothing capacitor, and 12 and 13 are resistors for adjusting the current supplied to the light emitting diode 10. The light emitted from the light emitting diode 10 is detected by the phototransistor 14, and the discrimination circuit 20 operates based on this signal. The output of this discrimination circuit 20 is guided to a relay or a display device by a well-known method to detect that the armature T of the motor is in a locked state. 5
Here, the integrating circuit 16 is provided to prevent the discriminating device 20 from malfunctioning due to an excessively negative voltage when starting the motor.

In addition, Doki light emitting diode 10 and phototransistor 1
In consideration of the ease of coupling and the stability of operation, it is preferable to use a well-known photocoupler that is integrated with the optical coupler 4. With this photocoupler, the half-separated circuit 20 is electrically isolated from the motor drive circuit, thereby reducing the risk of malfunction due to noise. Further, the zero rotation detection circuit 3 is a circuit that does not require a control power source, and the circuit configuration is simple and the operation is stable. The lock detection device of the present invention described in detail above has a simple mechanism, stable operation, and does not require a separate control power source, so it can be easily installed in various power devices using series-wound commutator motors. can.

Furthermore, the output of the lock detection device facilitates feedback control such as stopping the operation of various devices that use a series commutator motor as power, so it can be used extremely effectively in various applications.

[Brief explanation of the drawing]

FIG. 1 is a wiring diagram of an embodiment of the lock detection device of the present invention, and FIGS. 2 and 3 are voltage-current waveform diagrams when the motor is under light load and when the motor is locked, respectively. 1...Power circuit, 2...Electric motor, 3.
...Zero rotation detection circuit.

Claims (1)

[Claims] 1. When a half-wave phase-controlled series commutator motor is in a locked state, the inductance of the armature winding of the series commutator motor causes the power supply to switch off during the negative cycle of the power supply. A lock detection device for a series commutator motor, characterized by comprising a zero rotation detection circuit that detects a negative voltage applied until it becomes zero. 2 The zero rotation detection circuit consists of a rectifier circuit that extracts the detected voltage from both ends of the armature winding separately from the motor power supply, and an optical coupling circuit that sequentially converts the output of this rectifier circuit into electrical, optical, and electrical signals and transmits them. 2. A lock detection device for a series-wound commutator motor according to claim 1, further comprising: a discrimination circuit for discriminating a detection signal from an output of an optical coupling circuit.