CN2162023Y

CN2162023Y - Electronic protective starter for electric motor

Info

Publication number: CN2162023Y
Application number: CN 93224286
Authority: CN
Inventors: 张德祥
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-09-17
Filing date: 1993-09-17
Publication date: 1994-04-13
Anticipated expiration: 2003-09-17

Abstract

The utility model relates to a motor starter with various electronic protection functions, which is composed of a DC power supply, a given voltage circuit of over current action, an over current detecting circuit, a phase-failure detecting circuit, a state memory circuit, an actuator and an acoustic-optic alarm circuit. The utility model has the advantages of high sensitivity, accurate given current, simple usage method, wide adaptability range of motor power, etc.

Description

Electronic protective starter for electric motor

The utility model relates to a kind of threephase asynchronous starter, especially a kind of motor starter with multiple Electronic Protection function.

The damage phenomenon that motor is in operation and takes place, except that the cause for quality of motor own, the external factor of motor such as the phase failure, overload, short circuit, decompression etc. also are major reasons, the particularly phase failure and overload, wherein the phase failure is particularly important.The motor open-phase running be difficult for found; estimate according to the expert; the motor burnout failure that causes thus accounts for more than 2/3 of total accident; yet on motor starter, also there is not open phase protection; especially based on the device of Electronic Protection mode; usually only has overload protection; its critical piece is confined to use thermal relay again; it is very little that it adapts to the power of electric motor scope; regulating error is big; the heat action back restarting stand-by period is longer, and is installed in that motor interior is regulated and hand-reset is made troubles.

It is reliable that the purpose of this utility model provides a kind of sensitivity, and the operating current numerical value of adjusting is accurate, easy to adjust, has the motor starter with multiple Electronic Protection of failure cause demonstration and feedback control function.

The technical solution of the utility model is:

By the Electronic Protection starter that fuse, A.C. contactor CJ, current transformer HL, control circuit board and indicator light, buzzer and casing (1) etc. are formed, comprise the DC power supply (13) of input on the control circuit board by A.C. contactor CJ-1 or control relay J-1 control; Output voltage and all adjustable overcurrent of this voltage upper and lower limit scope move given potential circuit (14); The over-current detection circuit (15) that main circuit current is changed to be converted to change in voltage and to be in series with given voltage; One is the open-phase detection circuit (16) of test point with voltage between phase line asterism and the zero line; A state memory circuit (17) that is subjected to over-current detection circuit and open-phase detection circuit output to trigger control respectively; One be subjected to state memory circuit output potential control can cut off A.C. contactor CJ power supply, replace A.C. contactor CJ-1 contact to keep the executive module (18) and the acousto-optic alarm indication circuit (19) of DC power supply work again simultaneously.

The output voltage of DC power supply (13) is added in the branch road two ends that are in series by three potentiometers, and middle potentiometer output is taken over current detection circuit (15); The non-linear compensation circuit and the current transformer HL that are in series by resistance and two opposite polarity parallel diodes are in parallel, the ac voltage signal of output is through the time-delay of voltage multiplying rectifier and 10-65 second, and is in series with overcurrent action given circuit output voltage and is connected to the triggering input of state memory circuit (17).

One end of the electric capacity that three resistance same resistance or three capacitive reactances are identical joins with each phase line respectively, one end of another termination phase failure sense switch of each resistance, the switch other end is connected to the halfwave rectifier input, simultaneously also through isolation resistance and DC power supply rectifier bridge and zero line formation loop, the output of halfwave rectifier is connected to the triggering input of state memory circuit (17) through filtering, starts and stop button can be drawn with long line by the machine internal wiring terminal and done remote operation.

Further specify the technical solution of the utility model below in conjunction with drawings and Examples:

Fig. 1 is a schematic appearance of the present utility model;

Fig. 2 is an electric theory diagram of the present utility model;

Fig. 3 is an electrical schematic diagram of the present utility model.

As shown in Figure 1, cabinet (1) is made by steel plate, can be installed on control cubicle or other bracing frame by installing hole (2), be furnished with given electric current on the panel (3) and adjust knob (4) and given electric current scale thereof, phase failure sense switch (5), electric motor starting button (6), motor stop button (7) reaches draws binding post (8) accordingly, run indicator (9), overcurrent parking indicator light (10), phase failure parking indicator light (11), alarm sound hole (12), cabinet rear portion have three-phase and four-line input, lead-out terminal (accompanying drawing is not shown).

Embodiment shown in Fig. 2,3 presses electric motor starting button QA1 for rated current is the following Electronic Protection starter of 40A, and 220V voltage is exported the 12V direct voltage and is added in W behind CJ-1, C1 step-down, ZL, filtering voltage regulation ₁W ₂W ₃The overcurrent action voltage given circuit (14) that series arm is formed can be adjusted W according to the motor load situation ₁Select best overcurrent operating value in 0.7-1.2 times of scope of motor rated current, over-current detection circuit (15) is that output current with HL is through R ₃, D ₁, D ₂The non-linear compensation circuit of forming, C ₄C ₅D ₃D ₄Voltage multiplying rectifier, C ₅Filtering is at R ₄Obtain on the load resistance on a large scale in and the induced current linearity of HL pulsating voltage signal preferably, through R ₅C ₆Time-delay, its time constant is selected in second at 10-65 according to the ratio of electric motor starting electric current and rated operational current, and present embodiment is 20 seconds, C ₆On voltage and the given voltage of W1 be in series; its difference is less than 4 volts; state memory circuit (17) the output IC1-3 that 555 time-base circuits are constituted is high electric level ground; can keep IC1-3 through the anti-phase IC1-6 of exporting to of BG1 is high electric level ground; this electric level ground makes executive module electromagnetic relay J work through D6 on the one hand; J-1 disconnects; the CJ decompression; CJ-1 self holding contact and CJ-2; 3; 4 contacts all disconnect and have cut off Alternating Current Power Supply; protected motor; show the scram reason by luminous tube LED1 on the other hand; while buzzer FM sounding alarm; CJ-5 also disconnects after the CJ decompression, but is replaced by J-2 immediately, because the afterflow effect of C2C3 can not influence the operate as normal of DC power supply.

When motor normally moves; R6,7,8 the asterism that joins electricity value are 0 volt; asterism is for zero line generation voltage after the phase failure; reduce to about 2 volts through making IC2 trigger the input current potential behind the rectifying and wave-filtering; making IC2 state turnover IC2-3 immediately is high potential; operative scenario afterwards is ditto described, thereby finishes open phase protection.

In Electronic Protection starter circuit greater than the 40A rated operational current; can use intermediate relay ZJ replaced C J to reduce of the interference of CJ break-make to control circuit; increase the sensitivity of this starter for situation at big current work; move given potential circuit at overcurrent and increase the fast tripping protection circuit; shown in dotted line among Fig. 3 connects; move given electric current with suitable reduction overcurrent, this circuit is suitable for by the phase over-current detection.

The utility model has the following advantages:

1. the ratio of given electric current upper and lower limit reaches 4-5 doubly, can well cooperate with motor power (output), and the scope of application is wide, and versatility is good.

2. it is accurate that given electric current is regulated numerical value.

3. as long as not exceeding the quata to decide electric current, the adjustment load can not start immediately after the overload action.

4. using method is simple, and panel is regulated, self-resetting.

Claims

1, a kind of electric motor electron protection starter, form by fuse, A.C. contactor CJ, current transformer HL, control circuit board and indicator light, buzzer and casing (1) etc., it is characterized in that: comprise the DC power supply (13) of input on the control circuit board by A.C. contactor CJ-1 or control relay J-1 control; Output voltage and all adjustable overcurrent of this voltage upper and lower limit scope move given potential circuit (14); The over-current detection circuit (15) that main circuit current is changed to be converted to change in voltage and to be in series with given voltage; One is the open-phase detection circuit (16) of test point with voltage between phase line asterism and the zero line; A state memory circuit (17) that is subjected to over-current detection circuit (15) and open-phase detection circuit (16) output to trigger control respectively; One is subjected to the A.C. contactor CJ power supply that can cut off of state memory circuit output potential control to replace A.C. contactor CJ-1 contact to keep the executive module (18) and the acousto-optic alarm indication circuit (19) of DC power supply work again simultaneously.

2, a kind of electric motor electron protection starter as claimed in claim 1, it is characterized in that: described overcurrent action voltage given circuit (14) and over-current detection circuit (15) are that the output voltage with DC power supply (13) is added in the branch road two ends that are in series by three potentiometers, and the potentiometer output of centre is taken over current detection circuit (15); The non-linear compensation circuit and the current transformer HL that are in series by resistance and two opposite polarity parallel diodes are in parallel, the ac voltage signal of output is through the time-delay of voltage multiplying rectifier and 10-65 second, and is connected to the triggering input of state memory circuit (17) after being in series with overcurrent action given circuit (14) output voltage again.

3, a kind of electric motor electron protection starter as claimed in claim 1; it is characterized in that: described open-phase detection circuit (16) is that the end by the identical electric capacity of three resistance same resistance or three capacitive reactances joins with each phase line respectively; one end of another termination phase failure sense switch of each resistance; the switch other end is connected to the halfwave rectifier input; also through isolation resistance and DC power supply rectifier bridge and zero line formation loop, the output of halfwave rectifier is connected to the triggering input of state memory circuit (17) through filtering simultaneously.

4, a kind of electric motor electron protection starter as claimed in claim 1, it is characterized in that: startup and stop button can be drawn with long line by cabinet (1) internal wiring terminal and be done remote operation.