JPS63181790A - Abnormality protector of washing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an abnormality protection device for a washing machine for washing household clothes.

BACKGROUND OF THE INVENTION Conventionally, an abnormality protection device for a washing machine of this type has a configuration as shown in FIG. In FIG. 6, 1 is an AC power source, 2 is a power switch, and 31L.

3b is a semiconductor switching device (hereinafter referred to as a triac), 4 is a motor, and 5 is a phase advance capacitor. A control circuit 6 controls the motor 4 by controlling the triacs sa and 3b on and off by a control drive circuit 60 comprising a microcomputer in response to signals from an operation display circuit 61. When the triac 31L or 3b fails and becomes short-circuited, a large current flows through the motor 4 and the temperature rises, causing the fuse 7 to short-circuit the coil of the motor 4.
A common method was to prevent large currents from flowing and igniting.

Problems to be Solved by the Invention In such a conventional configuration, there is a risk that the shifter 7 may not be shut off due to a knock on the fuse 7 or the like, which may cause the shifter 4 to catch fire.

The present invention is intended to solve these problems, and aims to detect triac failure, stop the load drive output, cut off the power supply, and prevent abnormal temperature rises in the motor. .

Means to Solve the Problem In order to solve this problem, the present invention detects the terminal voltage of the motor phase advancing capacitor, and when the terminal voltage is abnormal,
It is designed to cut off the power.

Function: With this configuration, it is possible to prevent an abnormal temperature rise in the motor when the triac fails, or abnormalities such as the motor not stopping rotating, thereby realizing a safer washing machine.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 5. In FIG. 1, 1 is an AC power supply, 2' is a power switch that can be electrically interrupted, 3a, 3
b is a triac for controlling the motor 4, and 6 is a motor phase advance capacitor.

A control circuit 6 drives a triac 8 which releases the mechanical latches of the triacs sa, 3b and the power switch 2' by magnetic drive.

Reference numeral 61 denotes an operation display circuit, which is composed of a key switch, a display element, etc., and is connected to the control drive circuit 6o.

62 is a capacitor terminal voltage detection circuit which detects the terminal voltage of the phase advance capacitor 5 and sends a signal V to the control drive circuit 60.
Add c.

FIG. 2 shows the terminal voltage waveform of the capacitor 5, when the person is normal, and B shows the waveform when the triac 31L or 3b is in a short-circuited state. If normal, triac 3a or 3b
When the capacitor is conductive, a voltage is generated at the capacitor terminals, and when it is off, no voltage is generated at the capacitor terminals. However, if one of the triacs fails, capacitor terminal voltage is generated when the faulty and short-circuited triac is controlled to conduct, and during the motor off period when triacs 3a and 3b are turned off, and if the normal triac is controlled to be conductive. , the terminal voltage of the capacitor 5 becomes almost zero voltage.

FIG. 3 shows an embodiment of a capacitor voltage detection circuit 62, in which a capacitor terminal voltage is applied to a full-wave rectifier circuit 621 through a resistor 620, and a 7-way coupler 622 is applied to the DC 5-base 7' output circuit. Connect.

The output voltage Vc of the photo coupler 622 is at LO level when the capacitor voltage is large, and is at Hi level when no capacitor voltage is generated. FIG. 4a shows the signal Vc under normal conditions, and FIG. 4b shows the waveform when the triac is faulty and short-circuited. The triac is turned off from on, and after a certain time Δτ, it is determined whether Vc is Hi or LO level, and it is determined whether the triac is malfunctioning or normal.

FIG. 4 shows a flowchart for detecting an abnormality during normal/reversal control of the motor. At step 600, it is determined whether the motor is in the off period, and when the motor is off, after providing a time delay, the signal V
When c is LoO, abnormality processing is performed and protective operation is performed. To handle the abnormality, turn off the triac for driving the washing motor,
The triac 8 is driven to release the mechanical latch of the power switch 2'.

As described above, according to this embodiment, the abnormality detection circuit has a simple circuit configuration consisting of a full-wave rectifier circuit and a photocoupler.
It is possible to detect a short circuit between two trialers using one signal, and a low-cost protection device can be realized. Although a mechanical latch type magnetic power switch is shown as an example of a power switch for cutting off the power, it is clear that a self-holding type relay can also provide the same effect.

Effects of the Invention As described above, according to the present invention, failure of the motor drive triac or triac drive circuit is detected, and abnormal temperature rise of the motor is prevented and rotation of the motor is stopped. In particular, it is possible to protect against abnormal temperature rise due to simultaneous triac conduction, which has been extremely difficult in the past, or abnormal temperature rise due to DC excitation due to triac half-wave conduction.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a washing machine protection device according to an embodiment of the present invention, and FIG. 2 is a diagram showing changes in capacitor voltage.
Figure 3 is a circuit diagram of the capacitor voltage detection circuit, Figure 4 is a diagram showing the output signal of the capacitor voltage detection circuit, Figure 5 is a flowchart showing abnormality detection and protection operation, and Figure 6 is a conventional washing machine. FIG. 7 is a block diagram showing a protection device of 7-1. 1... AC power supply, 2'... Power switch, 3a. 3b... Semiconductor switching device, 4...
...Motor, 5... Phase advance capacitor, 6...
...Control circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 4
Figure 5 Tool H≠ Figure 6

Claims (1)

[Claims] An AC power source, a power switch connected in series with the AC power source and capable of interrupting control, a semiconductor switching device, a motor, a phase advancing capacitor, and a control circuit for controlling the semiconductor switching device and the power switch, The semiconductor switching device controls normal rotation and reverse rotation of the motor by at least two semiconductor switching devices each connected to both terminals of the phase advance capacitor, and the control circuit detects the voltage at the terminals of the phase advance capacitor. An abnormality protection device for a washing machine, characterized in that the power switch is shut off in the event of an abnormality.