JPH01270782A - Fan - Google Patents

Abstract

PURPOSE:To attain low power consumption and high reliability by simultaneously applying a DC current to a sub coil and a main coil at the time of stopping duto to contact with a human body. CONSTITUTION:A SCR 2c is turned ON by the output of an electronic controller 12 at the time of normal operation. Thus, an AC power is supplied to a fan motor 1 to rotate the motor 1. When the part of a human body is brought into contact with a guard, the controller 12 turns OFF SCR 2c, ON SCR 4a by a signal from a contact detector 2a. Thus, the supply of AC power to the motor 1 is stopped. Simultaneously, SCR 4b, SCR 4e are turned ON, the DC power half-wave rectified and smoothed by the operations of a diode 4c and a capacitor 4e is supplied to the motor 1, thereby momentarily stopping rotation of the motor 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a safe household electric fan that instantly stops rotating its fan motor when a part of the human body touches a guard or the like.

2. Description of the Related Art In recent years, in order to ensure safety, electric fans have come into use that instantly stop the rotation of the fan motor when a part of the human body comes into contact with a guard. For example, it has been put into practical use with the model F-30MIQ manufactured by Matsushita Electric Industrial ■.

A conventional electric fan will be explained below.

Figure 2 shows a circuit diagram of a conventional electric fan, with fan motor 1
01, a control circuit 102 that controls the brake circuit 104, a step-down rectifier circuit 103 that converts a high-voltage AC voltage into a low-voltage DC power source, and a DC power supply stabilization circuit 106. first,
During normal operation, when the electronic control unit 112 in the control path entrance 102 turns on a switch (not shown), a signal is sent from the output terminal 112a to a bidirectional semiconductor switch (hereinafter referred to as SCR).
102 Turn on c. Further, the main coil /l/101a of the fan motor 101 is connected to the fixed terminal 114C of the relay 114 in the DC brake circuit 104, and the sub coil /L'101b is connected to the movable contact terminal 114b of the relay 114.
At this time, the fixed terminal 114C and the movable contact terminal 114b are electrically connected, so the main coil /1z
Electricity i flows through 101a and subcoil 1o1b, and fan motor 101 is operated. At the same time, a signal is also output from the output terminal 112b of the electronic control section 112, turning the 5CR104d into
Therefore, the high voltage DC power supply is rectified by the diode 104b and the capacitor 104C is charged. Next, when a part of the human body touches the guard, the contact detection section 102a amplifies the signal induced when the human body touches through the electrode 5 connected to the guard (not shown), and the electronic control section 1
12 is input.

Then, a signal is output from the output terminal 112C of the electronic control unit 112, turning on the transistor 104e, and the relay 114 is activated to establish electrical continuity between the fixed terminal 114C and the movable contact terminal 114a. At this time, the 5CR 104d is in the ON state, half-wave rectified DC power is applied to the main coil/l/101a of the fan motor 101, and the fan motor 101 is applied with a DC brake and stops rotating instantly. After that, the electronic control unit 112 and 5CFL 104cl are turned OFF, the DC brake on the fan motor 101 is released, and then the transistor 104e is turned OFF and the relay 11
The connection between the fixed terminal 114c and the movable contact terminal 114b of No. 4 is restored to return to the normal state. Here, the fan motor 101
When applying the DC brake to the Subcoy/l/101b
If DC power is applied to the iron core (not shown) of the fan motor 1Q1, a phenomenon occurs in which magnetic flux does not flow to a supersaturated state and the fan motor 101 does not stop completely due to the influence of current ripple due to half-wave rectification. Main carp/L
'DC current is flowing only through 101a.

Problems to be Solved by the Invention However, since the above-mentioned conventional configuration uses the relay 114, the relay coil has a large excitation current, which requires the use of a heavy and expensive transformer in the step-down rectifier circuit. However, there was a problem that defects were likely to occur due to wear of the relay contacts. Further, even if an attempt is made to replace the conventional relay contact with a semiconductor switch, since it is inserted between the diode 104b and the fan motor 1o1, the potential of the entire semiconductor switch is unstable and cannot be directly controlled by the electronic control unit 112. It had

The present invention solves the above-mentioned conventional problems, and provides a stable potential to the semiconductor switch of the DC brake circuit and controls it directly from the electronic control unit, reduces current consumption, reduces weight, and has high reliability. The purpose is to provide a fan with low parts cost.

Means for Solving the Problem In order to achieve this object, the electric fan of the present invention includes a fan motor having a coil that can withstand a large DC current, a DC brake circuit that stops the fan motor suddenly, and a guard that protects the fan from the human body. It consists of a control section that detects contact and activates the brake circuit, and a power supply section that converts alternating current into direct current. a first semiconductor switch that controls the operation of the fan motor, and a second semiconductor switch that controls the DC brake circuit;
The DC brake circuit includes a diode and a capacitor connected in series that half-wave rectify AC power and apply it to the fan motor, a third semiconductor switch that controls conduction of the diode, and a fourth semiconductor switch that controls conduction of the capacitor. the second semiconductor switch is configured to control the third and fourth semiconductor switches.

Effect: With this configuration, when a DC brake is applied, when a DC current is simultaneously applied to the main coil and sub-coil of the fan motor, a large current flows through the coil, and the coil withstands this large current and sends supersaturated magnetic flux to the iron core of the fan motor. The fan motor can be stopped instantaneously because it is not affected by current ripple caused by half-wave rectification.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows a circuit diagram of an electric fan according to an embodiment of the present invention. That is, it consists of a DC brake circuit 4 that suddenly stops the fan motor 1, a control circuit 2 that controls the brake circuit 4, and a power supply section 3 that converts and stabilizes a high-voltage AC power source into a low-voltage DC power source. The fan motor 1 has one end connected to a power supply section 3, and the other end connected to a control circuit 2 and a DC brake circuit 4. The control circuit 2 is an electronic control section 1
2 is the same as the conventional model except that it has two output terminals compared to the conventional model. Here, the DC brake circuit 4 includes a diode 4C and a capacitor 4d connected to the fan motor 1.
5CR4b which controls the connection of the diode 4C to one end of the power supply, and 5CR4e which controls the connection of the capacitor 4d to the other end of the power supply, and is controlled by the electronic control unit 12 to control the 5CR4b and 5CR4e. 5CR4
It has a.

The operation of the electric fan of this embodiment configured as described above will be described below. First, during normal operation, the control circuit 2
A driving instruction is input to the T-child control section 12 inside the vehicle using a switch (not shown), and 5CR2c is turned on. As a result, AC power is supplied to the fan motor 1, and the fan motor 1 rotates. At this time, since 5CR4a is OFF, 5CR4b and 5CR4e controlled by it are also OFF.
FF, no current flows through the diode 4c and the capacitor 4e, and the DC brake circuit 4 has no effect on the rotation of the fan motor 1. Next, a case will be described in which a part of the human body touches the guard and the electric fan is stopped instantly.The electronic control unit 12 turns 5CR2C OFF and 5CR4a ON based on the signal from the contact detection circuit 2a. As a result, AC power supply to the fan motor 1 is stopped, and at the same time, 5CR4b and SCR controlled by 5CR4a
+e turns on, diode 4C and capacitor 4
Half-wave rectified and smoothed DC power is supplied to the fan motor 1 by the action of e, and the fan motor 1 instantly stops rotating. Here, the main coil 1a of the fan motor 1,
Since a sufficiently large current can flow through the sub coil/L/1b until the magnetic flux flowing through the iron core (not shown) becomes oversaturated, the fan motor 1
never rotates. At this time, the electronic control section 12 only needs to have two output terminals, 12a and 12b, which can be reduced by one compared to the conventional case. Furthermore, since there is no relay excitation coil that consumes power, the DC power consumption can be kept low, and a lightweight and inexpensive voltage drop resistor can be used instead of a power transformer for the electric τ source. A few seconds after the fan motor 1 stops, the electronic control unit 2b
Turn R4a OFF, set DC brake circuit 4 to normal operation, detect that there is no contact with the guard, and turn S C
Turn on R2c to enter normal operating state.

As described above, according to this embodiment, a fan motor having a coil that can withstand a large DC current is used, and by simultaneously applying half-wave rectified DC power to the subcoil and the main coil, the relay is eliminated and the SCR is achieved. Since it is possible to configure a DC brake circuit using the contact point, power consumption can be reduced, weight can be reduced, and compared to mechanical contacts, high reliability can be achieved in terms of life and vibration, and component costs can be reduced. can. Furthermore, the number of control terminals in the electronic control section can be reduced, and the power transformer in the power supply section can be replaced with a voltage drop resistor due to lower power consumption.

In addition, in this embodiment, the DC brake circuit is a diode 4C.
5CR4b was used, but any combination of a diode and a one-way semiconductor switch may be used as long as it is a diode equivalent circuit that can perform ON-OFF control.

Effects of the Invention As is clear from the description of the embodiments described above, the present invention uses the main coil and sub-coil of a fan heater as coils that can withstand large DC current, and simultaneously applies DC current to the sub-coil/I/ and the main coil when contact with a human body is stopped. This allows us to eliminate the relay in the DC brake circuit and replace it with SCH, resulting in an excellent electric fan that has the benefits of low power consumption, high reliability, and lower component costs. It is possible.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of an electric fan showing one embodiment of the present invention;
The figure is a circuit diagram of a conventional electric fan. 1...Fan motor, 2...Control unit,
2a...Contact detection section, 2c...Semiconductor switch, 3...Power supply section, 4...DC brake circuit, 4a, 4b, 4e... ...semiconductor switch, 4c...diode)', ad...
...Capacitor. Name of agent: Patent attorney Toshio Nakao and one other person
69221,4 e' - Shiliang

Claims (1)

[Claims] A fan motor has a coil that can withstand a large DC current, a DC brake circuit that suddenly stops the fan motor, a control unit that activates the brake circuit by sensing when a human body touches the guard of the fan, and The control section has an input side connected to a contact detection section for detecting human body contact, and an output side connected to a first semiconductor switch for controlling the operation of the fan motor, and the control section is connected to the DC brake circuit. The DC brake circuit includes a diode and a capacitor connected in series that half-wave rectifies AC power and applies it to the fan motor, and a third semiconductor switch that controls conduction of the diode. An electric fan comprising a semiconductor switch and a fourth semiconductor switch that controls conduction of the capacitor, the second semiconductor switch controlling the third and fourth semiconductor switches.