CN2468145Y

CN2468145Y - Electronic combined switch

Info

Publication number: CN2468145Y
Application number: CN 00230922
Authority: CN
Inventors: 朱仲彦
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-09-22
Filing date: 2000-09-22
Publication date: 2001-12-26
Anticipated expiration: 2010-09-22

Abstract

The utility model provides an electronic combined switch. Both ends of various switches or contactor contacts are connected in parallel with branch circuits formed by that thyristors or contacts are connected in series with resistors; different characteristics of the resistors can be selected according to different service application; the resistors can be NTC-form or PTC-form high-energy electronic ceramic resistors. The NTC-form high-energy electronic ceramic resistors are used, and a soft start function can be realized to a motor load; the PTC-form high-energy electronic ceramic resistors are used, non-arc switch can be realized to alternating current-direct current switches, faults and short-circuit currents can be limited, and harmful switching overvoltage can also not be generated in the process of switching-on and switching-off.

Description

Electronic combination switch

The utility model provides a kind of electronic combination switch, belongs to the alternating current-direct current high and low voltage switch

Technical field.

Fail in power technology, join, the power supply field, the conventional circuit breaker that uses, on-load switches such as A.C. contactor, in the process of load switching, can produce electric arc (or spark) and switching overvoltage, especially when big failure of current inductive load, the serious scaling loss and the harmfulness switching overvoltage of switch main contact takes place easily.For alleviating the degree of switch main contact scaling loss, usually need to adopt arc-extinguish chamber or with the arc extinguishing measure of dielectrics such as vacuum, oil, SF6, not only make the manufacturing technology process complexity, the contact material of the low Chopping Current that switch contact is required, present domestic Cu Cr alloy material commonly used, Japan is AgWc, the CoAgSe alloy material of exploitation recently, cost an arm and a leg, and switch in use need often safeguard (polishing) because of the ablation of contact, and useful life is short, poor reliability.At present disclosed Arcless AC Contactor has all been done certain effort in this field as patents such as 95232323,97229337.But all unresolved the high-voltage large current occasion can arc extinguishing again can soft switching, the technical problem of strict control harmfulness switching overvoltage.

The purpose of this utility model is to utilize the temperature characterisitic of high energy electron ceramic resistor, solves harmfulness overcurrent, overvoltage and arc extinguishing problem in high-voltage large current occasion load switching process.

The technical solution of the utility model is: this electronic combination switch mainly comprises the main contact K of all kinds of switches and is attempted by the ON-OFF control circuit at main contact two ends, its ON-OFF control circuit is attempted by main contact K two ends after by switch D series connection high energy electron ceramic resistor Rt, and switch D can be contact switch or noncontacting switch.

Above-mentioned electronic combination switch, its switch D adopts noncontacting switch, as controllable silicon so that control.

Above-mentioned electronic combination switch, its resistance R t adopt high energy NTC type electronic ceramic resistance, and its characteristic satisfies that resistance is 1-4 Ω under the room temperature, reduces to after the heating below 0.2 Ω, and this scheme is particularly suitable for motor soft start type electronic combination switch.

Above-mentioned electronic combination switch, its resistance R t adopt high energy PTC type electronic ceramic resistance, and its characteristic satisfies that resistance is 0.1-0.2 Ω under the room temperature, heating back resistance 〉=10 ³Ω, this scheme is particularly suitable for high-voltage great-current branch, combined floodgate arc extinguishing and short circuit and overcurrent protection.

The utility model has the advantages that:

1. use the electronic combination switch of high energy NTC type electronic ceramic resistance, be waveform with sine wave change from small to big (See Figure) fully in the process of the stator voltage of motor starting, thereby can realize level and smooth soft-start feature, it does not produce electrical network pollutes, and the waveform that changes the motor stator voltage swing compared with employing adjusting thyristor operating angle size is far better.

2. high energy PTC type electronic ceramic resistance device mainly plays two effects in circuit: the one, and when switch main contact K tripping, the electric current change of current is to SCR AC bridge and PTC device, and especially when short circuit or overcurrent, it plays the effect of fault current limiting.The thyristor bridge group is played the current-limiting protection effect.The 2nd, the PTC device can make resistance sharply increase because of electric current flows through intensification, the characteristic curve of its resistance is seen accompanying drawing 7, as can be seen from Figure, the resistance of each sheet PTC electronic ceramic resistance is very little under the room temperature, about about 0.2-0.4 Ω, along with passing through when the intensification of slice, thin piece reaches Curie point of electric current, its resistance sharply rises to 10 ³Ω～10 ⁶(Japan can accomplish 10 to Ω at present ⁸Ω), this just makes the electric current in the branch road, even when controllable silicon hinders for some reason and can not turn-off, circuit also can turn-off voluntarily because of Rt presents high resistance.This not only can realize the no electric arc separating brake of switch, can also avoid switch to produce the harmfulness switching overvoltage in the process of disjunction.3. DC electronic unit switch, its key wiring diagram is seen accompanying drawing 4.Controllable silicon is difficult to realize turn-offing as switch in DC circuit, and its main cause is after opening because of controllable silicon, can not turn-off voluntarily because of there being reverse voltage.This electronic combination switch is owing to be serially connected with high energy PTC resistance in the branch road, and when the circuit flow overcurrent, PTC resistance sharply increases because of the heating resistance, and for example the supply voltage in the circuit is DC500V, and the PTC resistance rises to 10 because of electric current flows through heating ⁵During Ω, then the electric current in the circuit is I=500/100000=5ma, and it is significantly smaller than silicon controlled and keeps electric current, and controllable silicon can turn-off voluntarily, thereby has solved the highly difficult technology of cut-offfing of D.C. high-current.

Below accompanying drawing is described: Fig. 1 motor soft Starting Technology scheme, Fig. 2 are that alternating electron unit switch technical scheme, Fig. 3 are that technical scheme, Fig. 4 that the alternating electron unit switch is used for the star-like connection of three-phase is DC electronic unit switch technical scheme, K is that main switch contact, D are control switchs among the figure, and it represents contact, the Rt of noncontacting switches such as controllable silicon or contact switch is electronic ceramic resistance.Fig. 5 is that performance plot, Fig. 6 of NTC electronic ceramic resistance is the performance plot of PTC type electronic ceramic resistance, and T representation temperature, R represent resistance among the figure.

Narrate embodiment of the present utility model below in conjunction with accompanying drawing:

1. motor soft start type electronic combination switch

Usually the starting current during the threephase asynchronous across-the-line starting is a 4-8 times of rated current.If net capacity is big inadequately, then the impulse current during motor starting may make line voltage significantly descend, and directly influences the motor (stall) under same electrical network and the normal operation of electric equipment.Adopt the electronic combination switch shown in the accompanying drawing 1 for this reason, the main contact K and the ON-OFF control circuit that is attempted by the main contact two ends that mainly comprise all kinds of switches, its ON-OFF control circuit is attempted by main contact K two ends after by switch T series connection high energy electron ceramic resistor NTC, and switch D can be contact switch or noncontacting switch.The course of work of electronic combination switch is: when motor puts into operation, trigger SCR AC bridge group (or contact of closed D) earlier, owing in this branch road, be serially connected with high energy NTC electronic ceramic resistance R t, Rt is bigger at the initial resistance of starting moment, the big pressure drop of the last generation of Rt, play the restrictions motor starting current, realized the purpose of reduced voltage starting.The continuous heating up of electric current work done on Rt thereupon, the Rt resistance constantly reduces, motor speed is corresponding thereupon increases, when reaching rated speed, the Rt resistance also approaches minimum stationary value, makes motor stator voltage near line voltage, at this moment the switch main contact K closure after time-delay, make switch D and resistance R t withdraw from motor work loop, finish the process of motor soft start.The characteristic of resistance R t is seen accompanying drawing 5, and at room temperature the resistance of every NTC is about 2-4 Ω.When motor in starting process, because electric current flows through the NTC slice, thin piece, along with improving constantly of slice, thin piece temperature rise, resistance can progressively descend thereupon, when temperature reached 200 ℃, resistance can be reduced to about 0.1-0.2 Ω, made motor stator voltage near line voltage, at this moment the switch main contact K closure after time-delay is finished the process of motor soft start.The time of motor soft start is selected the time parameter of NTC as required, can be from several seconds to tens seconds.When motor is out of service, failure of current can must be adopted the mode of break impulse to turn-off the electric current of this branch road to ac thyristor bridge group, or adopts alternate manner to cut off the contact switch of D.

2. alternating electron unit switch (seeing accompanying drawing 2 and 3)

This branch road of elder generation's conducting SCR AC bridge (can be full control AC bridge or half control AC bridge) serial connection high energy PTC electronic ceramic resistance, switch main contact k is connected in time-delay then; Elder generation's tripping main contact k, the high energy PTC electronic ceramic resistance circuit of time-delay excision switch D and serial connection again when switch trip.Utilize Opposed crossing voltage to turn-off electric current in the branch road.Particularly the electric current of PTC device flows through intensification and can make resistance sharply increase (characteristic curve of its resistance is seen Fig. 7), as can be seen from Figure, the resistance of each sheet PTC electronic ceramic resistance is very little under the room temperature, about about 0.2-0.4 Ω, along with passing through when the intensification of slice, thin piece reaches Curie point of electric current, its resistance sharply rises to 10 ³Ω～10 ⁶(Japan can accomplish 10 to Ω at present ⁸Ω), this just makes the electric current in the branch road, even when controllable silicon hinders for some reason and can not turn-off, circuit also can turn-off voluntarily because of Rt presents high resistance.This not only can realize the no electric arc separating brake of switch, can also avoid switch to produce the harmfulness switching overvoltage in the process of disjunction.The used high energy PTC electronic ceramic resistance R t of the utility model satisfies:

Ie.Rt≤30V is Rt≤30V/Ie

Wherein: the rated current in the Ie-circuit

Resistance when the Rt-room temperature is 25 ℃.

Another effect in circuit of high energy PTC type electronic ceramic resistance device is that the electric current change of current is to SCR AC bridge and PTC device branch road when switch main contact K tripping, and especially when short circuit or overcurrent, it plays the effect of fault current limiting.The thyristor bridge group is played the current-limiting protection effect.The utility model directly is attempted by the K two ends with high energy PTC electronic ceramic resistance, as long as Rt satisfies above-mentioned condition, just can eliminate the electric arc of switch contact, but because high energy PTC device can only be under certain voltage and current condition, and can only in the limited time, bear limited energy, it is tolerating high voltage, big electric current for a long time, adopts the high back-pressure silicon controlled method of serial connection for this reason, solves high energy PTC resistance and can not be applied to a difficult problem in the high voltage switch circuit for a long time.

3. DC electronic unit switch (its key wiring diagram is seen accompanying drawing 4)

Controllable silicon is difficult to realize cut-offfing as switch in DC circuit, and its main cause is because controllable silicon is opened the back because of there not being reverse voltage not turn-off voluntarily.This electronic combination switch is owing to be serially connected with high energy PTC resistance in the branch road, and when the circuit flow overcurrent, PTC resistance sharply increases because of the heating resistance, and for example the supply voltage in the circuit is DC500V, and the PTC resistance rises to 10 because of electric current flows through heating ⁵During Ω, then the electric current in the circuit is I=500/100000=5ma, and it is significantly smaller than silicon controlled and keeps electric current, and controllable silicon can turn-off voluntarily.

So, can utilize high energy PTC to turn-off controllable silicon in the dc switch field.The course of work of DC electronic unit switch is: when electronic combination switch trips, disconnect main contact k earlier, the electric current change of current is to the controllable silicon branch road, cut off the silicon controlled trigger impulse then, intensification along with the PTC slice, thin piece, its resistance constantly increases, and the electric current in branch road is kept electric current less than silicon controlled and turn-offed.We can realize the highly difficult technology of cut-offfing of D.C. high-current with this principle.

Because of control circuit all is a routine techniques, the relevant controlling circuit no longer describes in detail in the various embodiments described above.If the capacity of high energy electron ceramic resistor is not enough, can takes the mode of series and parallel to make up and meet the demands.

Claims

1, a kind of electronic combination switch, it mainly comprises the main contact K of all kinds of switches and is attempted by the ON-OFF control circuit at main contact two ends, it is characterized in that being attempted by main contact K two ends after ON-OFF control circuit is by switch D series connection high energy electron ceramic resistor Rt;

2, electronic combination switch according to claim 1 is characterized in that switch D adopts the noncontacting switch controllable silicon.

3, electronic combination switch according to claim 1 and 2 is characterized in that resistance R t adopts high energy NTC type electronic ceramic resistance, and its characteristic satisfies that resistance is 1-4 Ω under the room temperature, reduces to after the heating below 0.2 Ω.

4, electronic combination switch according to claim 1 and 2 is characterized in that resistance R t adopts high energy PTC type electronic ceramic resistance, and its characteristic satisfies that resistance is 0.1-0.2 Ω under the room temperature, and heating back resistance is 〉=10 ³Ω.