CN2273917Y

CN2273917Y - Phase interruption protective device for ac electric motor

Info

Publication number: CN2273917Y
Application number: CN 96239104
Authority: CN
Inventors: 石德仁; 李俊鹏; 刘培章; 孙少谦
Original assignee: TONGREN ELECTRIC APPLIANCE CORP SHENYANG
Current assignee: TONGREN ELECTRIC APPLIANCE CORP SHENYANG
Priority date: 1996-11-15
Filing date: 1996-11-15
Publication date: 1998-02-04
Anticipated expiration: 2006-11-15

Abstract

The utility model relates to a phase interruption protective device for an ac electric motor, comprising a shell, a relay TC, diodes D< 1 >-D< 6 >, electric condensers C< 1 >-C< 3 >, a transistor TR, a diode ZD and resistors R< 1 >-R< 2 >. The utility model is characterized in that a bridge-type circuit which is composed of diodes D< 1 >-D< 4 > is used as the dc power supply of the triodes. A neutral-point displacement circuit is formed by that the electric condensers C< 1 >-C< 3 > are connected in parallel. The influence of the utility model because of ambient temperature is small. Once the phase interruption phenomenon occurs, the transistor TR is conducted, and the relay TC is attracted to drive an AC contactor MC to release and cut off power supply so that the goal of protecting an electric motor is reached.

Description

Alternating current motor falls the phase protector

The utility model relates to the technical field of motor or equipment emergency protective device, and particularly a kind of alternating current motor falls the phase protector.

Alternating current motor is widely used in each industrial circle; owing to falling mutually and protecting burning of motor that improper reason causes to account for motor and damage 85% of sum; the main cause that causes motor to burn is to fall mutually or single phasing; electric current increases 1.7--1.8 doubly; not timely tripping operation outage source; cause burning of motor; at present employedly fall the phase protector; it mainly is the principle of root a tree name thermal effect; in protector, be provided with a bimetal leaf, when electric current increases; when temperature raises, bi-metal plate deformed; power supply disconnects; reach the purpose of protection motor, its shortcoming is to be subjected to the influence of ambient temperature bigger, is difficult to realize correct protection; another shortcoming is that the model that the phase protector is fallen in requirement must be complementary with power of electric motor, and versatility is poor.

It is little that the purpose of this utility model provides a kind of ambient temperature that is subjected to, the non-thermal effect type, and the alternating current motor that versatility is good falls the phase protector.

The purpose of this utility model is to realize like this, it comprises housing, relay TC, diode D1--D6, capacitor C1--C3, triode TR, diode ZD and resistance R 1--R2 is characterized in that forming the DC power supply of bridge circuit as triode by diode D1--D4, are provided with voltage stabilizing didoe ZD at the base terminal of triode, capacitor C1--C3 formation in parallel neutral point displacement circuit, the two ends of relay TC are connected with the collector electrode of triode, the negative pole of diode D5--D6 respectively.

The utility model is not owing to adopt the bimetal leaf structure; so be subjected to the influence of ambient temperature less; in case the phase phenomenon occurs falling; between the base stage of triode TR and emitter-base bandgap grading, produce forward voltage; triode RT conducting; relay TC adhesive also drives A.C. contactor MC and discharges, cuts off the electricity supply, and reaches the purpose of protection motor.

Below in conjunction with accompanying drawing the utility model is further described,

Fig. 1 is the schematic diagram that alternating current motor falls the phase protector,

Fig. 2 is the circuit diagram of Fig. 1,

As Fig. 1--shown in 2; this alternating current motor falls the phase protector and comprises housing 1; relay TC; diode D1--D6; capacitor C1--C3; triode TC; Zener diode ZD and resistance R 1--R2; form the DC power supply of bridge circuit by diode D1--D4 as triode TR base stage; base terminal at triode is provided with voltage stabilizing didoe ZD; capacitor C1--C3 is in parallel to constitute the neutral point displacement circuit, and it can guarantee E point and F point equipotential in three bridge circuits when being conducted, the two ends of relay TC respectively with the collector electrode of triode; the negative pole of diode D5--D6 is connected; when the phase phenomenon appears falling in power supply; E point current potential is higher than the current potential that F is ordered, and produces forward voltage between the base stage of triode TR and the emitter-base bandgap grading, because diode D5 and D6 have the characteristic of unidirectional conducting; electric current is through diode D5 or D6; relay TC; triode TR constitutes the loop; triode TR conducting, relay TC adhesive also drives A.C. contactor MC release; cut off the electricity supply, reach the purpose of protection motor.

Claims

1; a kind of alternating current motor falls the phase protector, and it comprises housing, relay TC; diode D1--D6; capacitor C1--C3, triode TR, diode ZD and resistance R 1--R2; it is characterized in that forming the DC power supply of bridge circuit as triode by diode D1--D4; base terminal at triode TR is provided with voltage stabilizing didoe ZD, capacitor C1--C3 formation in parallel neutral point displacement circuit, and the two ends of relay TC are connected with the collector electrode of triode, the negative pole of diode D5--D6 respectively.