CN2556829Y

CN2556829Y - Protector for electric machine

Info

Publication number: CN2556829Y
Application number: CN 02267977
Authority: CN
Inventors: 陈德新
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-06-27
Filing date: 2002-06-27
Publication date: 2003-06-18
Anticipated expiration: 2012-06-27

Abstract

The utility model discloses a motor protector which comprises an external shell and an electric circuit, being characterized in that the electric circuit comprises a current detection and sampling circuit 2 which is connected with an electronic recognition, time-delaying and control circuit 3, and the electronic recognition, time-delaying and control circuit 3 is connected with a working power circuit 4 which is connected with an executive circuit 1. The utility model which is simple in structure, reliable in operation, comprehensive in protection, convenient in regulation, sensitive in reaction and long in service life, integrating the protection functions, such as overload, high-low pressure vacant phase, motor locked rotation and short circuit into a whole.

Description

A kind of motor protecter

(1) technical field: the utility model relates to a kind of protector, relates in particular to a kind of motor protecter.

(2) background technology: present electric motor protective device; mainly contain thermal relay formula and electronic type two big classes; there are a lot of defectives in the thermal relay formula, as influenced by ambient temperature big, and poor reliability; slow in reacting; life-span is short, and electric current accommodation is little, the motor that a kind of specification can only supporting several power stages time; line contacts is many, has more increased the probability that breaks down.

In the electronic type electric motor protector, practical have current detecting formula that Current Transformer does and detect and temperature sensor be installed in temperature detection formula on the motor windings.

The secondary induction voltage of the current transformer that current detecting formula motor protecter is adopted; owing to restricted by the iron core magnetic saturation; can only change in of the variation of little electric current section with primary current; running status with its reaction motor is difficult; aspect open-phase protection; mostly be that to utilize the corresponding phase current of phase shortage rear motor be zero; the instrument transformer secondary induction voltage also is zero to come design protection device circuit; this is effective for the low pressure phase shortage; and when high pressure (10KV) phase shortage; because coupling between transformer high-low pressure winding and motor windings; make the low-pressure side three-phase voltage constant substantially, the corresponding phase current of motor institute is also non-vanishing, just reduces than normal current; and other biphase current increases; obvious above-mentioned protector circuit is invalid to high voltage open-phase protection, restricted by core sataration, and most protectors have only phase shortage and defencive functions such as overloading free stall; or, the little defective of electric current accommodation is also arranged just in little electric current Duan Youqi function.

For the motor protecter with design for temperature sensor, though need take motor apart is installed on motor internal with temperature sensor in protection, and needs to be equipped with respective lead comprehensively, obvious not all motor, occasion, user can generally use.

At electronic protector aspect motor control loop combines, mostly be to utilize the relay normally-closed contact to be series in the control loop of motor, when current anomaly, differentiate through interlock circuit, the relay adhesive, its normally-closed contact disconnects, the contactor power failure tripping, this mode has several point defects: the one, and protector working power and interlock circuit break down, and relay can't adhesive, in case the motor abnormality consequence is apparent; The 2nd, the relay contact arcing of easily ablating, it is unreliable to work; The 3rd, can only be used for the control loop of hand starting motor and can't be applied to that the application scenario is restricted in the control loop of automatic (as pressure, liquid level, temperature ...) starter motor.

(3) summary of the invention: the purpose of this utility model be to improve the deficiency of above-mentioned prior art and provide a kind of simple in structure, reliable, protection is comprehensive, easy to adjust, be quick on the draw, long service life, integrate the motor protecter of defencive functions such as overload, high-low pressure phase shortage, motor rotation blockage, short circuit.

The purpose of this utility model can reach by following measure: a kind of motor protecter; it comprises shell and electronic circuit; it is characterized in that electronic circuit comprises current detecting sample circuit 2; current detecting sample circuit 2 connects electronic recognition, time-delay, control circuit 3; electronic recognition, time-delay, control circuit 3 connect working power circuit 4, and working power circuit 4 connects executive circuit 1.

In order further to realize the purpose of this utility model, described current detecting sample circuit 2 comprises current transformer L1, L2, the end of current transformer L1 connects the positive pole of diode V7, the end of current transformer L2 connects the positive pole of diode V8, the negative pole of the other end of the other end of current transformer L1, current transformer L2, filter capacitor C4, sampling voltage regulator potentiometer Rp connect the back earth terminal, the negative pole of diode V7 be connected the positive pole of filter capacitor C4 and the other end of sampling voltage regulator potentiometer Rp respectively after the negative pole of diode V8 links to each other.

In order further to realize the purpose of this utility model, described electronic recognition, time-delay, the identification division of control circuit 3 comprises voltage comparator A2, A3, A4, the time-delay part comprises resistance R 11, R12, R13, capacitor C 5, C6, C7, control section comprises voltage comparator A1, the positive input terminal of voltage comparator A2, the positive input terminal of A3, the positive input terminal of A4 links to each other with the adjustable end of sampling voltage regulator potentiometer Rp after linking to each other, the negative input end of voltage comparator A2 connects resistance R 5 respectively, R6, the other end of resistance R 6 connects the negative input end of resistance R 7 and voltage comparator A3 respectively, the other end of resistance R 7 connects the negative input end of resistance R 8 and voltage comparator A4 respectively, the other end of resistance R 8 connects resistance R 9 and switch S respectively, the other end of resistance R 9 respectively with sampling voltage regulator potentiometer Rp, the positive pole of LED 2, capacitor C 5, C6, C7, C8, resistance R 15,12 pin of voltage comparator A4,12 pin of voltage comparator A1, the positive pole of voltage-stabiliser tube V2 links to each other and earth terminal, the other end of resistance R 5 connects the positive input terminal of resistance R 4 and voltage comparator A1 respectively, the other end of resistance R 4 respectively with 3 pin of voltage comparator A2, resistance R 10, resistance R 11, resistance R 12, resistance R 13, resistance 14 is connected in the Vcc end, 3 pin of voltage comparator A3,3 pin of voltage comparator A4,3 pin of voltage comparator A1 link to each other with the Vcc end respectively, 12 pin of voltage comparator A3, the 12 pin earth terminals of voltage comparator A2, the other end of resistance R 10 respectively with the output of voltage comparator A4, the negative pole of isolating diode V9, the positive pole of LED 2 links to each other, the other end of resistance R 11 connects the positive pole of isolating diode V9 respectively, the positive pole of isolating diode V12, the other end of capacitor C 5, the other end of resistance R 12 connects the output of voltage comparator A3 respectively, the positive pole of isolating diode V11, the other end of capacitor C 6, the other end of resistance R 13 connects the output of voltage comparator A2 respectively, the positive pole of isolating diode V10, the other end of capacitor C 7, the other end of resistance 14 links to each other with the output of voltage comparator A1, the negative input end of voltage comparator A1 respectively with the negative pole of isolating diode V10, the negative pole of V11, the negative pole of V12 links to each other, and the negative pole of isolating diode V10 links to each other with the other end of resistance R 15 again.

In order further to realize the purpose of this utility model, described working power circuit 4 comprises power transformer E, the elementary two ends of power transformer E connect V, the W two-phase power supply of motor respectively, the secondary two ends of power transformer E connect the input of bridge rectifier V3-V6, the output head anode of bridge rectifier V3-V6 connects the positive pole of capacitor C 3,1 pin of three terminal regulator N1 respectively, the negative pole of output end of bridge rectifier V3-V6 connects the negative pole of

capacitor C

3,2 pin of three terminal regulator N1 respectively, and 3 pin of three terminal regulator N1 connect electronic recognition, time-delay, control circuit 3.

In order further to realize the purpose of this utility model, described executive circuit 1 comprises piezo-resistance RU, the end of piezo-resistance RU connects the T2 utmost point of bidirectional triode thyristor Vs respectively, the positive pole of diode V1, the other end of piezo-resistance RU connects the T1 utmost point of bidirectional triode thyristor Vs respectively, capacitor C 2, the anodal back earth terminal of voltage-stabiliser tube V2, the control utmost point of bidirectional triode thyristor Vs connects the negative pole of LED 1 respectively, resistance R 3, the other end of capacitor C 2, the positive pole of LED 1 connects resistance R 2 respectively, resistance R 3, capacitor C 1, the negative pole of diode V1 connects resistance R 1, the other end of resistance R 1 connects the other end of resistance R 2 respectively, the other end of capacitor C 1, the negative pole of voltage-stabiliser tube V2, the end of piezo-resistance RU is by the button-S1 in electric motor starting loop,-S2, coil K links to each other with the U of motor main power source, and the other end of piezo-resistance RU links to each other with working power circuit 4.

Compared with the prior art the utility model has outstanding substantive distinguishing features and obvious improvement: for solving the easily saturated problem of common current transformer iron core; the utility model has adopted the current transformer of iron core band gap; be characterized in that iron core magnetic resistance strengthens; magnetic flux reduces; be difficult for saturated; primary current is pacified from several the peace to hundreds of; but its secondary induction voltage is respective change all; but it is non-linear changing; this characteristic just in time meets the needs of motor overload protection; iron core gap can be fixed, also can make adjustable, the whole protecting device only with two current transformers promptly possess from the overload; the high-low pressure phase shortage; motor rotation blockage; all measuring abilities of short circuit.And it is the electronic relay of core that the utility model adopts bidirectional triode thyristor; contactless and autostart function arranged; when being used for automatic control circuit; behind the fault trip; can automatically lock in off position; R11 wherein; C5; R12; C6; R13; C7 forms delay circuit provides three kinds of different delay tripping times according to the fault current difference; motor is carried out omnibearing protection, so the utility model is simple in structure; reliable; protection comprehensively; easy to adjust; be quick on the draw; long service life; the collection overload; the high-low pressure phase shortage; motor rotation blockage; defencive functions such as short circuit are in one.

(4) description of drawings:

Fig. 1 is an electric theory diagram of the present utility model;

Fig. 2 is a circuit connection diagram of the present utility model.

(5) embodiment: preferred forms of the present utility model is elaborated below in conjunction with accompanying drawing: a kind of motor protecter is (referring to Fig. 1-Fig. 2); it comprises shell and electronic circuit; electronic circuit comprises current detecting sample circuit 2; current detecting sample circuit 2 connects electronic recognition, time-delay, control circuit 3; electronic recognition, time-delay, control circuit 3 connect working power circuit 4, and working power circuit 4 connects executive circuit 1.Current detecting sample circuit 2 comprises current transformer L1, L2, the end of current transformer L1 connects the positive pole of diode V7, the end of current transformer L2 connects the positive pole of diode V8, the negative pole of the other end of the other end of current transformer L1, current transformer L2, filter capacitor C4, sampling voltage regulator potentiometer Rp connect the back earth terminal, the negative pole of diode V7 be connected the positive pole of filter capacitor C4 and the other end of sampling voltage regulator potentiometer Rp respectively after the negative pole of diode V8 links to each other.Electronic recognition, time-delay, the identification division of control circuit 3 comprises voltage comparator A2, A3, A4, the time-delay part comprises resistance R 11, R12, R13, capacitor C 5, C6, C7, control section comprises voltage comparator A1, the positive input terminal of voltage comparator A2, the positive input terminal of A3, the positive input terminal of A4 links to each other with the adjustable end of sampling voltage regulator potentiometer Rp after linking to each other, the negative input end of voltage comparator A2 connects resistance R 5 respectively, R6, the other end of resistance R 6 connects the negative input end of resistance R 7 and voltage comparator A3 respectively, the other end of resistance R 7 connects the negative input end of resistance R 8 and voltage comparator A4 respectively, the other end of resistance R 8 connects resistance R 9 and switch S respectively, the other end of resistance R 9 respectively with sampling voltage regulator potentiometer Rp, the positive pole of LED 2, capacitor C 5, C6, C7, C8, resistance R 15,12 pin of voltage comparator A4,12 pin of voltage comparator A1, the positive pole of voltage-stabiliser tube V2 links to each other and earth terminal, the other end of resistance R 5 connects the positive input terminal of resistance R 4 and voltage comparator A1 respectively, the other end of resistance R 4 respectively with 3 pin of voltage comparator A2, resistance R 10, resistance R 11, resistance R 12, resistance R 13, resistance 14 is connected in the Vcc end, 3 pin of voltage comparator A3,3 pin of voltage comparator A4,3 pin of voltage comparator A1 link to each other with the Vcc end respectively, 12 pin of voltage comparator A3, the 12 pin earth terminals of voltage comparator A2, the other end of resistance R 10 respectively with the output of voltage comparator A4, the negative pole of isolating diode V9, the positive pole of LED 2 links to each other, the other end of resistance R 11 connects the positive pole of isolating diode V9 respectively, the positive pole of isolating diode V12, the other end of capacitor C 5, the other end of resistance R 12 connects the output of voltage comparator A3 respectively, the positive pole of isolating diode V11, the other end of capacitor C 6, the other end of resistance R 13 connects the output of voltage comparator A2 respectively, the positive pole of isolating diode V10, the other end of capacitor C 7, the other end of resistance 14 links to each other with the output of voltage comparator A1, the negative input end of voltage comparator A1 respectively with the negative pole of isolating diode V10, the negative pole of V11, the negative pole of V12 links to each other, and the negative pole of isolating diode V10 links to each other with the other end of resistance R 15 again.Working power circuit 4 comprises power transformer E, the elementary two ends of power transformer E connect V, the W two-phase power supply of motor respectively, the secondary two ends of power transformer E connect the input of bridge rectifier V3-V6, the output head anode of bridge rectifier V3-V6 connects the positive pole of capacitor C 3,1 pin of three terminal regulator N1 respectively, the negative pole of output end of bridge rectifier V3-V6 connects the negative pole of

capacitor C

3,2 pin of three terminal regulator N1 respectively, and 3 pin of three terminal regulator N1 connect electronic recognition, time-delay, control circuit 3.Executive circuit 1 comprises piezo-resistance RU, the end of piezo-resistance RU connects the T2 utmost point of bidirectional triode thyristor Vs respectively, the positive pole of diode V1, the other end of piezo-resistance RU connects the T1 utmost point of bidirectional triode thyristor Vs respectively, capacitor C 2, the anodal back earth terminal of voltage-stabiliser tube V2, the control utmost point of bidirectional triode thyristor Vs connects the negative pole of LED 1 respectively, resistance R 3, the other end of capacitor C 2, the positive pole of LED 1 connects resistance R 2 respectively, resistance R 3, capacitor C 1, the negative pole of diode V1 connects resistance R 1, the other end of resistance R 1 connects the other end of resistance R 2 respectively, the other end of capacitor C 1, the negative pole of voltage-stabiliser tube V2, the end of piezo-resistance RU is by the button-S1 in electric motor starting loop,-S2, coil K links to each other with the U of motor main power source, and the other end of piezo-resistance RU links to each other with working power circuit 4.

During use, link to each other the brief description operation principle as shown in Figure 2 with motor:

Electric motor starting operation and protector are regulated: at first sampling voltage regulator potentiometer Rp inhour is screwed into the end; S closes; Q closes, under power supply and electric equipment normal condition, press the start button executive circuit get through K electric, by the V1 rectification; the R1 current limliting; the V2 voltage stabilizing, the control utmost point of Vs is through starting capacitor C 1; R3 must conduct, the K adhesive; motor rotation; LED1 is bright, L1; L2 has electric current to pass through, and E gets and electricly provides working power for protector; along with the C1 charging finishes; the Vs trigger current changes by working power to be provided through R14, when the current of electric normal duty is relatively stable, till regulating RP clockwise and making LED2 just luminous; this moment A4 positive input terminal; the negative input end current potential approximately equates (being made as 0.5V); S is separated, because the reference voltage a that seals in of R8 rises (being made as 0.6V), the A4 output becomes low level; LED2 goes out, and motor runs well.Motor is in service as load is unstable, can cause the electric current shakiness, LED2 is neglected brightly go out suddenly, belongs to normal phenomenon, C5 charging when bright, in case LED2 goes out in less than setting-up time, C5 institute charging voltage can not influence motor and run well through the discharge of V9 to A4 output.

Overload protection: when motor overload (being made as 20%); sampling voltage will be higher than the 0.6V reference voltage, and the A4 output becomes high level, and LED2 is bright; C5 charges through R11; through V12 A4 negative input end current potential is raise gradually, when in setting-up time, (establishing 5 minutes), when the negative input end of A1 is higher than positive input terminal reference voltage d; output becomes low level; Vs loses trigger voltage and turn-offs, the K power failure tripping, and motor stops.Start capacitor C 1 through the R2 discharge, fault can restart again after getting rid of.

Open-phase protection: when no matter motor is in operation high pressure or low pressure phase shortage; U, W two-phase have at least a phase or biphase current to increase, because phase shortage causes that electric current is bigger, impel sampling voltage to be higher than b point (being made as 0.8V) reference voltage; the A3 output is a high level; C6 charges through R12, through V11 the negative input end current potential of A1 is raise gradually, in setting-up time (being made as 1 minute); when the negative input end of A1 is higher than positive input terminal reference voltage d; the A1 output is a low level, and VS turn-offs, and repeats said process.

Motor rotation blockage, short-circuit protection: when make owing to power supply, motor or mechanical aspects reason motor can't startup, stall, short circuit etc.; to cause very big electric current; sampling voltage will be higher than c point (being made as 1V) reference voltage, and making the A2 output is high level, and C7 charges through R13; through V10 the negative input end current potential of A1 is raise gradually; in setting-up time (being made as 6 seconds), when the negative input end of A1 was higher than positive input terminal reference voltage d, the A1 output was a low level; VS turn-offs, and repeats said process.

When the utility model is used in the automatic control loop of motor, executive circuit will have electricity all the time behind the fault trip, but owing to start capacitor C 1 charging voltage be arranged, so can not restart, have only through cutting off the electricity supply, fix a breakdown, C1 discharges through R2, then can restart.

Claims

1, a kind of motor protecter; it comprises shell and electronic circuit; it is characterized in that electronic circuit comprises current detecting sample circuit (2); current detecting sample circuit (2) connects electronic recognition, time-delay, control circuit (3); electronic recognition, time-delay, control circuit (3) connect working power circuit (4), and working power circuit (4) connects executive circuit (1).

2; a kind of motor protecter according to claim 1; it is characterized in that described current detecting sample circuit (2) comprises current transformer L1; L2; the end of current transformer L1 connects the positive pole of diode V7; the end of current transformer L2 connects the positive pole of diode V8; the other end of current transformer L1; the other end of current transformer L2; the negative pole of filter capacitor C4; sampling voltage regulator potentiometer Rp connects the back earth terminal, the negative pole of diode V7 be connected the positive pole of filter capacitor C4 and the other end of sampling voltage regulator potentiometer Rp respectively after the negative pole of diode V8 links to each other.

3; a kind of motor protecter according to claim 1; it is characterized in that described electronic recognition; time-delay; the identification division of control circuit (3) comprises voltage comparator A2; A3; A4; the time-delay part comprises resistance R 11; R12; R13; capacitor C 5; C6; C7; control section comprises voltage comparator A1; the positive input terminal of voltage comparator A2; the positive input terminal of A3; the positive input terminal of A4 links to each other with the adjustable end of sampling voltage regulator potentiometer Rp after linking to each other; the negative input end of voltage comparator A2 connects resistance R 5 respectively; R6; the other end of resistance R 6 connects the negative input end of resistance R 7 and voltage comparator A3 respectively; the other end of resistance R 7 connects the negative input end of resistance R 8 and voltage comparator A4 respectively; the other end of resistance R 8 connects resistance R 9 and switch S respectively; the other end of resistance R 9 respectively with sampling voltage regulator potentiometer Rp; the positive pole of LED 2; capacitor C 5; C6; C7; C8; resistance R 15; 12 pin of voltage comparator A4; 12 pin of voltage comparator A1; the positive pole of voltage-stabiliser tube V2 links to each other and earth terminal; the other end of resistance R 5 connects the positive input terminal of resistance R 4 and voltage comparator A1 respectively; the other end of resistance R 4 respectively with 3 pin of voltage comparator A2; resistance R 10; resistance R 11; resistance R 12; resistance R 13; resistance 14 is connected in the Vcc end; 3 pin of voltage comparator A3; 3 pin of voltage comparator A4; 3 pin of voltage comparator A1 link to each other with the Vcc end respectively; 12 pin of voltage comparator A3; the 12 pin earth terminals of voltage comparator A2; the other end of resistance R 10 respectively with the output of voltage comparator A4; the negative pole of isolating diode V9; the positive pole of LED 2 links to each other; the other end of resistance R 11 connects the positive pole of isolating diode V9 respectively; the positive pole of isolating diode V12; the other end of capacitor C 5; the other end of resistance R 12 connects the output of voltage comparator A3 respectively; the positive pole of isolating diode V11; the other end of capacitor C 6; the other end of resistance R 13 connects the output of voltage comparator A2 respectively; the positive pole of isolating diode V10; the other end of capacitor C 7; the other end of resistance 14 links to each other with the output of voltage comparator A1; the negative input end of voltage comparator A1 respectively with the negative pole of isolating diode V10; the negative pole of V11; the negative pole of V12 links to each other, and the negative pole of isolating diode V10 links to each other with the other end of resistance R 15 again.

4; a kind of motor protecter according to claim 1; it is characterized in that described working power circuit (4) comprises power transformer E; the elementary two ends of power transformer E meet the V of motor respectively; the W two-phase power supply; the secondary two ends of power transformer E connect the input of bridge rectifier V3-V6; the output head anode of bridge rectifier V3-V6 connects the positive pole of capacitor C 3 respectively; 1 pin of three terminal regulator N1; the negative pole of output end of bridge rectifier V3-V6 connects the negative pole of capacitor C 3 respectively; 2 pin of three terminal regulator N1,3 pin of three terminal regulator N1 connect electronic recognition; time-delay; control circuit (3).

5; a kind of motor protecter according to claim 1; it is characterized in that described executive circuit (1) comprises piezo-resistance RU; the end of piezo-resistance RU connects the T2 utmost point of bidirectional triode thyristor Vs respectively; the positive pole of diode V1; the other end of piezo-resistance RU connects the T1 utmost point of bidirectional triode thyristor Vs respectively; capacitor C 2; the anodal back earth terminal of voltage-stabiliser tube V2; the control utmost point of bidirectional triode thyristor Vs connects the negative pole of LED 1 respectively; resistance R 3; the other end of capacitor C 2; the positive pole of LED 1 connects resistance R 2 respectively; resistance R 3; capacitor C 1; the negative pole of diode V1 connects resistance R 1; the other end of resistance R 1 connects the other end of resistance R 2 respectively; the other end of capacitor C 1; the negative pole of voltage-stabiliser tube V2; the end of piezo-resistance RU is by the button-S1 in electric motor starting loop;-S2; coil K links to each other with the U of motor main power source, and the other end of piezo-resistance RU links to each other with working power circuit (4).