JPH0716317B2 - Electric blower input control circuit - Google Patents

Description

The present invention relates to an input control circuit of an electric blower that changes the input of the electric blower by operating a slider of an operation circuit, for example.

(Prior Art) As a conventional input control circuit of an electric blower, for example, a configuration shown in FIG. 5 is known.

As shown in FIG. 5, the commercial AC power supply 11 includes a triac 14 having a snubber circuit 12 composed of a resistor and a capacitor, and an electric blower 15 connected in series with the commercial AC power supply 11. The blower 15 has a noise prevention capacitor 16.

A primary winding of a power transformer 20 is connected to the commercial AC power supply 11, a diode bridge 21 is connected to a secondary winding of the power transformer 20, and a resistor 22 is connected to the output side of the diode bridge 21. Also, a constant voltage circuit including the Zener diode 23 is connected.

A series circuit of a resistor 24 and a resistor 25 is connected in parallel with the zener diode 23, and a gate of a programmable unijunction transistor (PUT) 26 is connected to a connection point between the resistor 24 and the resistor 25. The cathode of the PUT 26 is connected to one end of the primary winding of the pulse transformer 27. A charging capacitor 28 is connected between the anode of the PUT 26 and the other end of the primary winding of the pulse transformer 27. Further, a stabilizing circuit 29 composed of a resistor and a diode is connected to the secondary winding of the pulse transformer 27, and is connected to the gate of the triac 14.

A resistor 31 is connected to the connection point between the resistor 22 and the resistor 24, and a resistor 32 is connected to the anode of the PUT 26.
Each of the 32 is connected to the operation circuit 33 of the hose.

Furthermore, this operation circuit 33 includes a resistance pattern 35 and a resistance pattern.
The conductive pattern 37 is connected to the resistor 31 via the resistor
The conductive pattern 33 is connected to and formed. Then, a first slider 39 is interposed between the resistance pattern 35 and the conductive pattern 38, and a second slider 40 is electrically connected between the conductive pattern 37 and the conductive pattern 38 so that they can slide. Connected to each other. Further, the first slider 39 and the second slider 40 are interlocked.

The resistance pattern 35, the conductive pattern 37 and the conductive pattern 38 are constructed as shown in FIG.
That is, the surface of both end portions of the resistance pattern 35 and the surfaces of the conductive pattern 37 and the conductive pattern 38 are coated with a low resistance material such as silver, and carbon for prevention of electrolytic corrosion due to migration etc. on the low resistance coating and sulfuration prevention. The compound is coated.

Further, the resistance value of the resistance pattern 35 shows a value as shown by the solid line A in FIG. 8, and when combined with the resistor 36, it becomes a combined resistance value shown by the solid line B.

Then, the resistance pattern 35 is set to a combined resistance value corresponding to the input of the electric blower 15. As a result, the output of the electric blower 15 decreases or increases. That is, the resistance pattern
The electric power input to the electric blower 15 is controlled by changing the resistance value of 35.

Further, as a device which uses a control element such as a triac to ignite at a zero cross of an AC power source, for example, Japanese Patent Laid-Open No. 59-
The configuration described in Japanese Patent No. 157722 is known. This patent
The configuration described in Japanese Patent No. 59-157722 is a configuration in which a phase control circuit using a tripod transformer is connected to the gate of a triac and zero crossing is ignited by using a slight lead phase of the tripod transformer.

(Problems to be Solved by the Invention) However, when the conventional operation circuit pattern shown in FIG. 6 is used in the circuit described in JP-A-59-157722, as shown in FIG. 15mA of allowable current shown in solid line A
If the current value is as low as the conventional one below, there will be no particular problem, but if a tripod transformer is used, the current value becomes high as shown by the broken line B, and sparks with the slider will occur in the large current range over 20 mA. It is likely to occur, and the carbon compound coating has holes, which causes abnormalities on the resistance surface and the slider, making it unusable.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an input control circuit for an electric blower that can be used for a relatively large current and that includes an inexpensive operation circuit.

[Structure of Invention]

(Means for Solving Problems) An input control circuit of an electric blower according to the present invention includes an electric blower connected in series to an AC power source, and a bidirectional control element having a gate for controlling the electric blower. A rectifying circuit for rectifying the alternating current of the AC power supply, a tripod core having a central leg and two outer legs, a primary winding wound on the one outer leg, and a secondary winding wound on the central leg A winding and a tertiary winding wound around the other outer leg, the primary winding being connected to both ends of the AC power supply, and one end of the tertiary winding being connected in antiparallel A tripod transformer connected to the gate of the bidirectional control element via a diode and having the other end connected to one end of the bidirectional control element, and the secondary winding connected to the rectifier circuit; A capacitor connected in series to the DC output terminal of the rectifying circuit, and An operating circuit for varying the output of the electric blower, an emitter is connected to the connection point between the capacitor and the operating circuit, a base is connected to one end of the DC output end of the rectifier circuit, and a DC output end is connected via two resistors. A first transistor having a collector connected to the other end, and a collector connected to one end of the DC output end of the rectifier circuit, an emitter connected to the other end, and a base connected to a connection point of the two resistors. A second transistor having a polarity opposite to that of the first transistor, and the operation circuit is connected to one of the rectifier circuit and the capacitor and the other of the rectifier circuit and the capacitor. Conductive pattern,
It has a plurality of variable resistors consisting of a slider that short-circuits and slides the resistance pattern and the conductive pattern, and terminals of the resistance pattern in the resistance value increasing direction and terminals of the resistance value decreasing direction are short-circuited. It is what

(Operation) The present invention triggers the bidirectional control element by the phase advance output of the tripod transformer to enable zero-phase ignition, and the terminals in the resistance value increasing direction of the resistance patterns of the plurality of variable resistors are connected to each other. Also, by short-circuiting the terminals in the direction of decreasing the resistance value, the current is shunted to increase the withstand power and withstand current value of the operating circuit, and even if a tripod transformer is used, it does not adversely affect the operating circuit. it can.

(Embodiment) An embodiment of the input control circuit of the electric blower of the present invention will be described below with reference to FIG.

As shown in FIG. 1, reference numeral 51 is a commercial AC power supply, and this commercial AC power supply 51 has a resistor 52 and a capacitor 53 connected in series.
A triac 55 as a bidirectional control element having a snubber circuit 54 composed of and is connected in series with an electric blower 56. In addition, electric blower 56 and commercial AC power supply 51
A noise prevention circuit 60 composed of Δ-connected capacitors 57, 58 and 59 is provided between and.

Further, 61 is a tripod transformer, and this tripod transformer 61 is a magnetic flux leakage type having a gap in the central leg, and has a primary winding 62 on one outer leg and a secondary winding 63 on the intermediate leg. A third winding 64 is wound around each of the other outer legs. And the primary winding 62
Are connected to both ends of the commercial AC power supply 51, one end of the tertiary winding 64 is connected to one end of the commercial AC power supply 51, and the other end of the tertiary winding 64 is connected in antiparallel to the diodes 65, 66, 67, It is connected to the gate of Triac 55 via 68.

Furthermore, the gate of this TRIAC 55 and commercial AC power supply 51
A capacitor 69 is connected between and, and a smoothing capacitor 70 is connected to both ends of the commercial AC power supply 51.

Also, the secondary winding 63 of the tripod transformer 61 is a diode 71, 72, 7
The AC input end of a diode bridge 75 as a rectifying circuit for full-wave rectification consisting of 3,74 is connected, and the DC output end of the diode bridge 75 is connected in series with a resistor 77, such as a hand-operated operating unit such as a hose. The operation circuit 78 and the capacitor 79 provided are connected, and the trigger control angle is determined by the RC time constant of the resistor 77, the operation circuit 78, and the capacitor 79.

Further, the emitter of a PNP transistor 80 as a first transistor is connected to the connection point between the operation circuit 78 and the capacitor 79, and the collector of the PNP transistor 80 is connected via a voltage dividing resistor 81 and a resistor 82. The diode bridge 75 is connected to the negative DC output end, the base is connected to the diode 83, and the diode bridge 75 is connected to the positive DC output end and the negative DC output end via the resistor 84.

Further, between the DC output terminal of the diode bridge 75, a collector and an emitter of an NPN transistor 85 as a second transistor which is a switching element for short circuit and has a polarity opposite to that of the PNP transistor 80 are connected.
The base of the mold transistor 85 is connected to the connection point of the resistors 81 and 82. A zener diode 86 for constant voltage is connected to the DC output terminal of the diode bridge 75.

Then, as shown in FIG. 2, the operation circuit 78 causes the resistor 77 to have a first resistance pattern via a transmission line in the hose, for example.
87 and a second resistance pattern 88 are connected, and the terminals of the first resistance pattern 87 and the second resistance pattern 88 in the direction of increasing the resistance value and the terminals of the direction of decreasing the resistance value are both short-circuited, A correction resistor 89 for error correction is connected in parallel with the second resistance pattern 87, 88. And
A first conductive pattern 91 and a second conductive pattern are provided at the connection point between the capacitor 79 and the emitter of the PNP transistor 80.
One end of 92 is connected.

Further, a first slider 93 is provided between the first resistance pattern 87 and the first conductive pattern 91, and a second resistance pattern 88 and a second resistance pattern 88 are provided between the first resistance pattern 88 and the second resistance pattern 88.
The second sliders 94 are provided between the conductive patterns 92 so as to be short-circuit slidable, and the first sliders 93 and the second sliders 94 work together. That is, the first resistance pattern 87, the first conductive pattern 91, and the first slider 93 form the first variable resistor 95, the second resistance pattern 88, the second conductive pattern 92, and the second conductive pattern 92. Slider 94 is the second variable resistor
The operation circuit 78 has two sets of variable resistors 95 and 96.

Then, these first and second resistance patterns 87, 88
In order to prevent a mechanical step from being formed in the increasing direction of the resistance value, the silver film is not formed up to the part where the resistance value is the minimum, and the resistance part is slightly left.

The resistance value of the first and second resistance patterns 87, 88 is about 25 kΩ, and the resistance value of the correction resistor 89 is about 37 kΩ. When two sets of variable resistors 95, 96 are connected in parallel, the resistance change curve Does not include both the rising and falling parts of the quadratic curve. That is, when the set of resistance values shown by the solid line A shown in FIG. 4 are combined, the combined resistance value shown by the solid line B is set so as to follow only the rising curve, and the instability of the operating circuit 78 is eliminated. .

The first and second resistance patterns 87 and 88 are the correction resistance 8
As shown in the equivalent circuit of FIG. 9 and FIG. 3, they are connected in parallel to reduce the error of the entire resistance value.

Next, the operation of the above embodiment will be described.

First, the voltage of the commercial AC power supply 51 is the primary winding of the tripod transformer 61.
It is applied to 62 and induces a voltage in the secondary winding 63. At this time, the magnetic flux is generated by the outer leg around which the primary winding 62 is wound and the secondary winding 63.
Almost no current is induced in the tertiary winding 64, since almost no current flows through the central leg having the wound gap.

The voltage induced in the secondary winding 63 is rectified by the diode bridge 75, and the first slider 93 and the second slider 93 are rectified.
The charging time of the capacitor 79 is determined according to the RC time constant determined by sliding 94 in conjunction. By charging this capacitor 79, the PNP transistor 80
Is turned on, and the PNP transistor 80 is turned on, so that a base current flows through the NPN transistor 85, the NPN transistor 85 is turned on, and the secondary winding 63 is short-circuited. As a result, a short-circuit current flows in the secondary winding 63, the magnetic flux in the central leg is saturated, and most of the magnetic flux flows in the outer leg, and the tertiary winding 64
A voltage is induced at. Then, the voltage controls the phase of the triac 55, controls the input power of the electric blower 56, and changes the output.

In addition, the first and second resistance patterns 87, 8 of the operation circuit 78
When the resistance value of 8 is set to the minimum, the resistance value is about 400Ω to 1kΩ which does not affect the charging time as shown in Fig. 4, so the charging time of the capacitor 79 is shortened and applied to the gate of the triac 55. Voltage is commercial AC power supply
The phase is slightly advanced from the voltage between the anode and cathode of the triac 55 applied by 51, and full ignition in the vicinity of the zero cross can be performed, and the electric power of the commercial AC power supply 51 can be input to the electric blower 56.

According to the above embodiment, the first and second variable resistors 95, 9
By providing two 6 in parallel, the current in the operation circuit 78 can be shunted, and the reduction and heating of the arc can be suppressed, so that the withstand current and withstand power of the operation circuit 78 are more than doubled. Further, since the first slider 93 and the second slider 94 slide in conjunction with each other, there are parallel contacts as compared with the case of one slider, so that the degree of concentration of current is reduced. Since it is less than 1/2, further, since it has a plurality of parallel contact portions, the rate of interruption of the current due to, for example, browsing is reduced, sparks are reduced, and the resistance patterns 87, 88 and the first and second conductive patterns 91 are reduced. The burden of 92 is also reduced and the service life can be extended.

Further, since the silver coating 97 is not completely provided in the vicinity of the resistance decreasing terminals of the resistance patterns 87 and 88 in consideration of a setting error and a mechanical step is eliminated, browsing and the like can be further avoided. If the silver coating 97 is provided just before the position of 0 mm in distance, the resistance value becomes the lowest and a mechanical step does not occur, which is optimal.

Further, according to the above-described embodiment, metal type resistors are used for the first and second resistance patterns 87, 88, and ceramics are used for the substrates of the first and second resistance patterns 87, 88. Since it is not necessary to increase the electric power, it is possible to use a carbon type operation circuit 78 that is the cheapest for mass production, has a permissible current of 15 mA, a permissible power of about 0.1 W, a resistance pattern, and a slider and a lever only. Therefore, a general inexpensive operating circuit 78 which could not be used in the past can be used for the circuit capable of zero-cross ignition with the least loss at the maximum input, and it can withstand a surge of about 5 to 6 times the maximum current. , And the first and second resistance patterns 87, 88 to 2
In any case, the process is almost the same as the conventional one, so that the control circuit can be constructed inexpensively and efficiently.

In addition, the polarities of the DC output of the diode bridge 75 of the circuit shown in FIG. 1 are reversed, the first transistor is an NPN type transistor, the second transistor is a PNP type transistor, and the polarities of the diode 83 and the zener diode 86 are opposite. You can also That is, the same operation is performed even if the biasing method and the direction of the output of the diode bridge 75 are changed.

The first and second variable resistors 95 and 96 are not limited to two sets, and three sets or more may be formed.

〔The invention's effect〕

According to the present invention, a plurality of variable resistors are provided in parallel by short-circuiting the terminals in the resistance value increasing direction and the terminals in the resistance value decreasing direction of the resistance patterns of the plurality of variable resistors to divide the current. Since the current in the operating circuit can be shunted by, the withstand current and power resistance of the operating circuit can be improved, and since the number of sliders increases and there are contact parts arranged in parallel, the resistance pattern Current concentration at
In addition, since the number of arcs can be reduced, the inexpensive operating circuit can be used for a relatively large current.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the same operating circuit as above, FIG. 3 is an equivalent circuit diagram showing the same operating circuit as above, and FIG. 4 is a graph showing resistance values as above. 5, FIG. 5 is a conventional circuit diagram, FIG. 6 is an explanatory diagram showing a conventional operation circuit, FIG. 7 is an equivalent circuit diagram of the same operation circuit as above, FIG. 8 is a graph showing resistance value as above, and FIG. It is a graph showing a current value same as above. 51 …… commercial AC power supply, 55 …… triac as bidirectional control element, 56 …… electric blower, 61 …… tripod transformer,
62 …… Primary winding, 63 …… Secondary winding, 64 …… Third winding, 6
5,66,67,68 …… Diode, 75 …… Diode bridge as rectifier circuit, 78 …… Operation circuit, 79 …… Capacitor, 80 …… PNP type transistor as first transistor, 81 …… Resistance, 82 ... Resistor, 85 ... NPN type transistor as second transistor, 87,88 ... Resistance pattern, 91,92 ... Conductive pattern, 93,94 ... Slider, 95,96
...... Variable resistor.

Claims (1)

[Claims] 1. An electric blower connected in series to an AC power supply; a bidirectional control element having a gate for controlling the electric blower; a rectifying circuit for rectifying the AC of the AC power supply; Tripod core having two outer legs, primary winding wound on the one outer leg, secondary winding wound on the central leg, and tertiary winding wound on the other outer leg A wire, the primary winding being connected to both ends of the AC power supply,
One end of the tertiary winding is connected to the gate of the bidirectional control element via a diode connected in antiparallel and the other end is connected to one end of the bidirectional control element, and the secondary winding is connected. A tripod transformer whose wire is connected to the rectifier circuit, a capacitor connected in series to the DC output end of the rectifier circuit, and an operation circuit for varying the output of the electric blower, and a connection point of the capacitor and the operation circuit A first transistor having an emitter connected to the base, one end of the DC output end of the rectifier circuit connected to the base, and a collector connected to the other end of the DC output end via two resistors; and a DC output end of the rectifier circuit. A second transistor having a polarity opposite to that of the first transistor having a collector connected to one end, an emitter connected to the other end, and a base connected to a connection point of the two resistors. The operation circuit includes a resistance pattern connected to one of the rectifier circuit and the capacitor, a conductive pattern connected to the other of the rectifier circuit and the capacitor, and a short circuit between the resistance pattern and the conductive pattern. A plurality of variable resistors composed of a moving slider, and terminals of the resistance patterns in the resistance value increasing direction and terminals of the resistance value decreasing direction are short-circuited. Input control circuit.