Novel mutual inductance type non-contact starter
Technical field
The utility model relates to a kind of novel mutual inductance type non-contact starter, is mainly used in the starting of compressor electric motor, also can be used for the starting of common single phase alternating current (A.C.) induction type or single-phase AC permanent-magnet formula motor, below is referred to as load motor.
Background technology
Load motor is formed by a rotor with by the stator that main winding and auxiliary winding constitutes usually.Auxiliary winding wherein also can continue to work when motor normally moves except the effect of playing electric motor starting, so the auxiliary winding circuit of complete load motor can be represented by the auxiliary winding operation circuit and the auxiliary winding starting circuit of parallel connection usually.When motor normally moved, the motor that auxiliary winding is not worked did not then have auxiliary winding operation circuit part wherein.Auxiliary winding starting circuit part is wherein only worked when electric motor starting, needs to realize disconnecting behind electric motor starting.Usually realize by semistor (PTC) element at present.When electric motor starting, starting circuit is worked, and the PTC element is led in the auxiliary winding starting current, causes the PTC element heating, and its resistance rises rapidly, and starting circuit is disconnected substantially.When motor normally moves, still must there be a less current to continue to pass through in the PTC element, to keep the heating resistance of PTC element, stop motor starting circuit when the motor operate as normal, to be had an effect.This power consumption of keeping the PTC heating is usually about 3W.Because this motor is widely used, this heating power consumption has caused a large amount of wastes of electric energy.
Chinese patent application CN1052228A discloses a kind of electronic circuit that is used for the start single phase induction motor.By bidirectional triode thyristor and the triggering/cut-off circuit thereof that in motor starting circuit, uses a normality to trigger, regularly end, realize that motor starting circuit is switched to the conversion that regularly disconnects from energising, thereby realize the starting of motor.But; this circuit uses the quantity of these discrete components for the so high situation of reliability requirements such as typical applications of long-term frequent intermittent starting; still reduced the reliability of starting circuit to a great extent; especially wherein employed resistive element and employed a plurality of transistors in the cut-off circuit regularly in the circuits for triggering; under electric machine operation state all by a plurality of milliamperes operating current is arranged; and this electronic circuit operates all in the machine operation circuit of complexity; do not realize effective isolation with complicated power utilization environment; the light current Circuits System of whole fragility can't obtain excellent protection, has brought huge negative for the reliability of whole electric system.Simultaneously, the bidirectional triode thyristor that adopts in this circuit is before motor starting circuit is connected, must realize resetting of timer, just must make the timer circuit dead electricity, after timer timing capacitor discharge is after a while finished substantially, could realize once more that the time-delay of bidirectional triode thyristor ends, otherwise, as long as there is electric current to exist in circuits for triggering/timing cut-off circuit, bidirectional triode thyristor will be in cut-off state always, can't realize the transformation of motor from the little current status of non-running to starting.
The Japanese documentation spy opens and has utilized motor in the starting principle different with electric current under the working order among the flat 10-94279, by placing current sense resistor at the motor total loop, is voltage signal by this resistance with main circuit current (motor total current) signal transition, this patent is set with one " reference current value setting apparatus " and " electric current comparison loop " simultaneously, main circuit current signal and setting current value are compared, with the break-make of the bidirectional triode thyristor that seals in this comparative result control motor starting circuit, thereby reach the purpose of controlling the starting circuit break-make.But used resistance that the current signal in the motor total loop is sampled into voltage signal in this circuit.Resistance is pure resistance element, and the electric current of motor total loop is usually all in the ampere level or near an ampere level, and like this, in the running of whole motor, this resistance is all at a useless heating power consumption that consumes watt level or approaching watt level.This circuit can also greatly reduce rate of energy under the situation of actuating motor.In addition, this circuit has used auxiliary circuits such as " reference current setting apparatus ", " comparison loop ", and the existence of these auxiliary circuits has all reduced the reliability of electric motor starting function to a certain extent.
Chinese invention patent 200410065370.X and 200510038234.6 discloses two kinds of mutual inductance type non-contact starters of applicant invention, is applicable to various dissimilar load motors respectively.The characteristics of these two kinds of mutual inductance type non-contact starters are to adopt current transformer, difference according to load motor, diverse location at motor circuit carries out sample conversion to electric current, be used for triggering the bidirectional triode thyristor that is serially connected in the motor auxiliary winding start loop, utilize motor at the beginning of starting in the loop electric current much larger than the characteristics of running current, when electric motor starting, trigger the auxiliary winding bidirectional triode thyristor and make its short time conducting, finish the starting of motor.And the utility model is different from the compound mode of Chinese invention patent 200410065370.X and 200510038234.6 by making Current Transformer and bidirectional triode thyristor, realizes the mutual inductance type power consumption starter.
Summary of the invention
The purpose of this utility model is that a kind of reliability height, novel mutual inductance type non-contact starter that consumed power is few will be provided.
The purpose of this utility model is achieved like this, a kind of novel mutual inductance type non-contact starter, comprise a current transformer L who contains a primary coil and a secondary coil, a bidirectional triode thyristor T and a semistor PTC, it is characterized in that 1 end of described current transformer L primary coil and an end of power end are connected with the end of semistor PTC, 2 ends of current transformer L primary coil and 4 ends of secondary coil are connected with motor main winding exit M, 3 ends of current transformer L secondary coil are connected with the trigger electrode G of bidirectional triode thyristor T, first utmost point A1 of bidirectional triode thyristor T is connected with the other end of semistor PTC, and second utmost point A2 of bidirectional triode thyristor T is connected with motor auxiliary winding exit S.
3 ends of current transformer L secondary coil described in the utility model are connected with an end of resistance R, and the other end of resistance R is connected with the trigger electrode G of bidirectional triode thyristor T.
The trigger electrode G of bidirectional triode thyristor T described in the utility model and the other end of resistance R are connected with the end of two-way trigger tube D, and first utmost point A1 of bidirectional triode thyristor T and the other end of semistor PTC are connected with the other end of two-way trigger tube D.
3 ends of current transformer L secondary coil described in the utility model are connected with the end of two-way trigger tube D with the trigger electrode G of bidirectional triode thyristor T, and first utmost point A1 of bidirectional triode thyristor T and the other end of semistor PTC are connected with the other end of two-way trigger tube D.
1,2 ends of current transformer L primary coil described in the utility model shunt resistance Rx in parallel.
The utility model is by making the current signal in the Current Transformer sampling electric motor loop, the effective heating power consumption of Control current sampling system, usually the power consumption of this sampling system can both be hanged down and be reached the milliwatt level, just so-called " zero-power " starter for AC electrical motor in single-phase, thus energy-saving efficiency improved greatly; In addition, circuit of the present utility model is simple, and number of elements is few and reliable, when having guaranteed the electric motor starting function, has improved the reliability of electric motor starting system.
Description of drawings
Fig. 1 is the electrical schematic diagram of the 1st kind of embodiment of the present utility model.
Fig. 2 is the electrical schematic diagram of the 2nd kind of embodiment of the present utility model.
Fig. 3 is the electrical schematic diagram of the 3rd kind of embodiment of the present utility model.
Fig. 4 is the electrical schematic diagram of the 4th kind of embodiment of the present utility model.
Fig. 5 is the electrical schematic diagram of the 5th kind of embodiment of the present utility model.
Fig. 6 is the electrical schematic diagram of the 6th kind of embodiment of the present utility model.
Fig. 7 is the electrical schematic diagram of the 7th kind of embodiment of the present utility model.
Fig. 8 is the electrical schematic diagram of the 8th kind of embodiment of the present utility model.
Embodiment
The utility model reaches this purpose by realizing a kind of mutual inductance type non-contact starter that is used for load motor.Referring to Fig. 1, Fig. 1 is embodiment 1.Load motor described here has by at least one main winding and the stator that auxiliary winding constitutes, between the main winding and auxiliary winding exit, can be connected with permanent operation capacitor C, motor main winding exit is M, motor auxiliary winding exit is S, it is Z that the motor main winding and auxiliary winding merges exit, and two tie points of electric system and outside single phase alternating current power supply are respectively A and B.The utility model is characterised in that above-mentioned mutual inductance type non-contact starter comprises: a current transformer L who contains a primary coil and a secondary coil, a bidirectional triode thyristor T and a semistor PTC, 1 end of described current transformer L primary coil is connected with the end of semistor PTC with power end A, 2 ends of current transformer L primary coil and 4 ends of secondary coil are connected with motor main winding exit M, 3 ends of current transformer L secondary coil are connected with the trigger electrode G of bidirectional triode thyristor T, first utmost point A1 of bidirectional triode thyristor T is connected with the other end of semistor PTC, and second utmost point A2 of bidirectional triode thyristor T is connected with motor auxiliary winding exit S.Be the described mutual inductance type non-contact starter of the utility model in the frame of broken lines among the figure.Power end A and power end B can exchange.
At the beginning of motor begins starting, because rotor does not also have high speed rotating, the motor circuit system has a bigger starting current and exists, and the primary coil of current transformer L is serially connected in the major loop of motor, so has a bigger secondary induction electric current corresponding to electric motor starting electric current in its primary coil in the secondary coil of current transformer.By selecting suitable current transformer L parameter can make this induced current be enough to trigger the bidirectional triode thyristor conducting, thereby motor starting circuit is connected entered operating state, at this moment, motor begins starting, its rotating speed rises rapidly, the semistor that is serially connected in the motor starting circuit then begins to have a bigger motor auxiliary winding starting current to pass through, and semistor generates heat rapidly, and its resistance value is risen rapidly.When its temperature reached the Curie-point temperature of semistor, its resistance value rose to a maximum, was enough to make motor starting circuit to disconnect substantially.At this moment, motor enters normal operating condition.After motor entered running status, the operating current of electric system also declined to a great extent near the normal operating conditions electric current, and the secondary induction electric current of current transformer also declines to a great extent, so that it can not trigger bidirectional triode thyristor.At this moment, motor starting circuit is disconnected fully, does not have electric current to pass through in the semistor, and its temperature begins to descend.When the temperature of semistor drops near operating ambient temperature, because this moment, motor was in normal operating condition, bidirectional triode thyristor in the starting circuit can not be triggered by the secondary output current of current transformer, there is not electric current to pass through in the semistor, semistor the motor stall and once more prestart do not have electric current by and the heating, motor starting circuit can keep this state always, stops operating up to motor.
Referring to Fig. 2, Fig. 2 is embodiment 2.Serial connection one resistance R by selecting suitable current transformer L parameter and current-limiting resistance R, can make induced current be enough to trigger the bidirectional triode thyristor conducting between 3 ends of bidirectional triode thyristor T trigger electrode G summation current transformer L secondary coil.
Referring to Fig. 3, Fig. 3 is embodiment 3.In embodiment 2, between first utmost point A1 of bidirectional triode thyristor T and trigger electrode G and met a two-way trigger tube D, bidirectional triode thyristor T is played protection and jamproof effect.
Referring to Fig. 4, Fig. 4 is embodiment 4.In embodiment 1, between first utmost point A1 of bidirectional triode thyristor T and trigger electrode G and met a two-way trigger tube D, bidirectional triode thyristor T is played protection and anti-interference effect.
Referring to Fig. 5-Fig. 8, Fig. 5-Fig. 8 is embodiment 5-8.To the shunt resistance Rx in parallel of the current transformer L primary coil two ends among the embodiment 1-4, this shunt resistance Rx is used for shunting the electric current of load motor major loop by current transformer L primary coil, plays jamproof effect simultaneously.