JPS6039394A - Speed controller of motor - Google Patents

Abstract

PURPOSE:To obtain a speed controller which has no possibility of electric shock by using a leakage 3-leg core transformer. CONSTITUTION:An operation side or detection side circuit A and a power source side circuit B are electrically insultated by a leakage 3-leg core transformer 17. When a variable oscillator 24 is operated to operate a device, the first secondary coil 22 becomes a shortcircuit state. Accordingly, a central nonopen leg 20 becomes magnetically saturated state, the magnetic flux is connected to an open leg 18, thereby forming a magnetic circuit as shown by a dotted chain line D. As a result, a voltage is induced in the second secondary coil 23. A contactless switching element 3 is conducted by the voltage induced at the coil 23, and the motor is rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a speed regulating device for electric motors applied to air conditioning equipment and combustion equipment.

Conventional Structure and Problems Conventionally, as a method of controlling the speed of an electric motor, as shown in FIG. 1, an electric motor 2 and a bidirectional 3. A non-contact switching element 3 such as a terminal xyrisk is connected in series, an ignition element 5 is connected to the gate 4 of the non-contact switching element, and a variable resistor 6 and a capacitor 7 are connected.
By varying the variable resistor 6 and varying the resistance value, the phase bending angle of the non-contact switching element 3 can be varied and the voltage can be increased. It was common to use a speed limiter of 1Jfi, but since the variable resistor 6 is connected to the AC power supply,
Insulation on the operation side (1
ζWhen attempting to automatically control the speed of an electric motor (fan, etc.) by detecting room temperature or water temperature using a heat-sensitive resistance element such as a thermistor, there may be problems with heat-sensing resistance elements and insulation considerations (to prevent electric shock). ) was necessary.

In order to eliminate the above insulation problem, as shown in FIG. 2, a rectifying element 8 is connected to the gate 4 of the non-contact switching element 3.
A secondary coil 10 of an isolation transformer 9 is connected to form an ignition circuit. The low voltage circuit of the rectifier circuit 13 is connected to the low voltage side of the insulation transformer 12, and the resistor 14.15 and PUT'1 are connected to the low voltage side of the isolation transformer 12.
The primary coil 11 of the isolation transformer 9 is connected to a relaxation circuit composed of a variable resistor 6, a variable resistor 6, and a capacitor 7.
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When performing temperature control, there is no risk of electric shock because the isolation transformers 9 and 12 are used to isolate the AC power supply.

However, there are disadvantages in that it requires two isolation transformers and is expensive.

Purpose of the Invention #4: To solve the problems of conventional insulation, connections, and costs, and to provide a speed control device that uses a single isolation transformer and is free from the risk of electric shock. .

Structure of the Invention In order to achieve the above-mentioned object, the speed control device for an electric motor of the present invention includes a leakage type 3III transformer, in which one leg of the three-leg iron core is an open row with a gap, and one non-open leg of the leakage type 3III transformer.
A primary coil connected to an AC power source is wound around the other non-open leg, and a first secondary coil whose both ends are connected to a variable oscillator is wound around the opening 1ν41 with a gap of mFJ.
A second secondary coil is wound, and 1) a non-contact switching element controlled by the output signal of the second secondary coil described in 11 is connected between both ends of the AC power source via an electric motor, With one isolation transformer, it is inexpensive, there is no risk of electric shock, and the circuit can be made compact.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 3, an electric motor 2 and a non-contact switching element 3 such as a two-way three-terminal silice are connected in series to both ends of an AC power source 1.

The operation side or detection side circuit A and the power supply side circuit B are electrically insulated by a leakage type three-leg iron core transformer 17. As shown in FIG. 4, in the 3II111 core transformer 17, 11111118 of the three core legs are open rows having a gap G, and the remaining two legs 19 and 20 are non-open legs. A primary coil 21 to which a predetermined AC voltage (usually 1oov) is applied is wound around one non-open leg 19, and a first secondary coil 22 is wound around the other non-open leg 2o. It's being passed around. The first secondary coil 22 and Ii! 1eia The voltage induced in the secondary coil 22 of the winding coil 211 of the primary coil 21 is a sufficiently low voltage (for example, 1
2■).

A variable oscillator 24 installed in an air conditioning device, a combustion device, etc. is connected to both parts 1 of the first secondary coil 22.

The variable oscillator 24 is configured to short-circuit the first secondary coil 22 (1).

Af A second secondary coil 23 is wound around the open leg 18 . The output terminal of the second secondary coil 23 is connected to the third
As shown in the figure, a rectifying element 8 is connected to the gate 4 of the non-contact switching element 3 to form an ignition circuit.

FIG. 5 shows an embodiment of the variable oscillator 24, in which the ignition element 27 is connected to the gate 26 of the non-contact switching element 25, and the variable oscillator 24 is configured by connecting it to the CR circuit of the variable resistor 2B and the capacitor 29. And the first secondary coil? Connected to 2.

Due to the charging characteristics of the CR circuit of the variable resistor 28 and the capacitor 29, the ignition element 27 is ignited, the jltE contact switching resistor 25 is brought into conduction, and the first secondary coil 22 is short-circuited.

The operation of the embodiment will be explained based on the drawings.

6<31114] The coil voltage of the iron core transformer 17 is shown, and both parts 1t17. of the primary coil 21 are shown. Box PX shows the voltage S1 across ψfFj of the first secondary coil 22 and the voltage S2 across the second secondary coil 23.

Normally, when the appliance is not operated, the magnetic flux generated by the primary coil 21 of the three-legged core transformer 17 is
As shown in FIG. 2, a magnetic circuit is formed through the central non-opening leg 111120, and a magnetic circuit cannot be formed toward the open leg 18 with the gap G because its magnetic resistance is large.

Therefore, no voltage is generated in the second secondary coil 23 wound around the opening llll118.

Therefore, the non-contact switching element 3 does not conduct and the electric motor 2
does not rotate.

Therefore, when the variable oscillator 24 is operated to operate the instrument, the non-contact switching element 25 becomes equal to j... and the first two
Since the next coil 22 is short-circuited, the central non-opening 20 becomes magnetically saturated, and the magnetic flux flows toward the open leg 18, forming a magnetic circuit as shown by the dashed line in FIG. do.

As a result, a voltage is induced in the second secondary coil 23. The voltage induced in the secondary coil 23 makes the non-contact switching element 3 conductive, and the electric 'IfJJ machine 2 rotates.

As shown in FIG. 6, the operation of the variable oscillator 24 is achieved by selecting the CR circuit of the variable resistor 28 and the capacitor 29 and conducting the non-contact switching element 25 so as to control the phase. Electricity induced in the secondary coil 23 [ES
Since the phase of the motor 2 can be controlled, the speed can be controlled by controlling the phase of the non-contact switching element 3 and controlling the electric motor 2 in a phase manner.

In the CR circuit of the variable oscillator 24, if the variable resistor 28 is a heat-sensitive resistance element attached to an air conditioner or combustion equipment that detects room temperature or hot water temperature, the room iy
It is possible to control the speed of the electric vj machine in conjunction with the water temperature and water temperature.

Effects of the Invention (1) It is possible to provide a speed control device for a motor with no fear of electric shock using a single isolation transformer.

(2) Since it is composed of one isolation transformer (three iron core transformers), the cost is low.

(3) It is insulated from the AC power supply, so there is no risk of electric shock due to the insulation when installing the heat-sensitive resistance element in equipment.

(4) The circuit becomes more compact.

[Brief explanation of drawings]

Figures 1 and 2 are circuit diagrams showing a conventional example, Figure 3 is a circuit diagram showing an embodiment of the present invention, Figure 4 is a configuration diagram of the transformer, and Figure 5 is a circuit diagram of the variable oscillator. , FIG. 6 is an output waveform diagram for explaining the same operation. 1... AC power supply, 2... Electric motor, 3 - Non-contact switching element, 17 - Leakage type three-legged transformer, 21 1
Secondary coil, 22. First secondary coil, 23. Second secondary Koinope. 24. Variable oscillator, 28. Variable resistor. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4 Figure 4

Claims (2)

[Claims] (1) One leg of the three-legged iron core is an open leg with a gear N knob.A primary coil connected to an AC power supply is wound around one non-open leg of a leaky three-legged transformer, and the other non-open leg is connected to an AC power supply. A first secondary coil is wound around the leg, both ends of which are connected to a variable oscillator.
A second secondary filter is wound around the opening leg provided with the gear N knob, and a non-contact switching element which is controlled by the output signal of the second secondary coil is connected via an electric motor. A speed control device for an electric motor connected between both ends of an AC power supply. (2) A variable oscillator constructed by connecting a non-contact switching element and the input signal of the non-contact switching element to a CR circuit via an ignition element.
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The resistance element of the CR circuit in the variable oscillator is used as a heat-sensitive resistance element for detecting room temperature or water temperature, which is installed in air conditioners and combustion equipment. If'K.