CN2073184U

CN2073184U - Open-phase protector for three-phase motor

Info

Publication number: CN2073184U
Application number: CN 90217716
Authority: CN
Inventors: 周天飞
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-08-07
Filing date: 1990-08-07
Publication date: 1991-03-13

Abstract

The utility model discloses three-phase motor open-phase protection device is a double-gate knife switch that connects in parallel separately on the arbitrary double-phase main fuser of three-phase motor, and another is met auxiliary relay mutually, and its normally open contact is even on ac contactor. One end of one side fuse in the double-switch knife switch is connected with the other side fuse which is larger than the melting point of the other side fuse, and the wire diameters of the connection positions of the two fuses are the same, so that the current is increased and the fuse is firstly fused when the phase is broken, and the motor stops running.

Description

Phase loss protector for three-phase electric motor

The utility model relates to a kind of threephase motor open phase protection.

Threephase motor occupies very big ratio because of open-phase running burns motor in the various faults of motor; develop various types of phase failure protectors for this reason; these protector great majority are electronic types; cost is higher; its less stable; and circuit is complicated; bring difficulty to maintenance work; because of electronic devices and components are corroded in chemical industry, high temperature, high acid environment easily; high temperature is also bigger to its influence; sensitivity is reduced, and it is unreliable to work, and can not effectively stop motor starting when motor outside line phase shortage.

It is reliable that the purpose of this utility model is to design a kind of surrounding environment influence, working stability of not being subjected to, the threephase motor open phase protection that cost is low, and it can guarantee in motor or motor is shut down during foreign minister's phase shortage.

Solution of the present utility model is double bladed knife swich in parallel separately on the main fuse of any two-phase of threephase motor, another is connected to auxiliary relay, the normally opened contact of this relay is connected on the coil that exchanges tentaculum, when this phase phase failure, the auxiliary relay no current passes through, its normally opened contact is still remained stationary, and A.C. contactor is failure to actuate, thereby the motor fail to start.One that is connected on a side fuse in the knife switch on other two-phase is connected on the fuse of opposite side greater than its fusing point, the line footpath that is connected the fuse junction is identical with the line footpath that is connected in its silk of insuring, when any phase phase failure of this two-phase, main fuse fusing, electric current flows through fuse through knife switch, the electric current of this moment is greater than the rated current of fuse, the most weak thereby the fusing at once of the ability to bear of fuse junction, A.C. contactor forces motor out of service owing to dead electricity restores to the original state.The utility model also can play a protective role to foreign minister's phase shortage, if foreign minister's power supply phase shortage because auxiliary relay and double bladed knife swich act in control loop, makes the electric current of control loop can not constitute the loop, motor can't start.

The utlity model has that circuit is simple especially, production cost is low; can adapt to the all-environment characteristics of different industries; reliable through the working stability that facts have proved this device, motor is loaded onto this device rear motor burn-out rate and is descended 90%, can both protect motor effectively when foreign minister or interior phase phase shortage.

Accompanying drawings the utility model:

The utility model is at the X of threephase motor ₁₁And X ₁₃Double bladed knife swich 1HK in parallel separately on main fuse 1RD, the 3RD of phase ₂, 2HK ₂Knife switch A side connects with the 10A fuse, the selection of B side fuse should be decided by the rated current melt size of A.C. contactor JC, generally select for use the fuse of 3-5A to be advisable, one with B side fuse is connected on the A side fuse, the line footpath of junction D is identical with the line footpath of B side fuse, knife switch 1HK ₂, 2HK ₂, B side holder another contact be connected with intermediate relay ZJ with stop button TA respectively, the comparable 1RD of the utility model main fuse 2RD, 3RD when motor operation phase shortage electric current increases, make 1RD or 3RD fusing more greatly.1HK under normal circumstances closes ₂, 2HK ₂, intermediate relay ZJ is passed through adhesive because of electric current is arranged, its normally opened contact ZJ1 closure; When pressing starting button QA, the A.C. contactor JC adhesive of switching on, make the normally opened contact JC closure of A.C. contactor in major loop, the electric motor starting running, current in loop increases when a phase phase failure, main fuse 1RD or 3RD fusing (because of 2RD greater than 1RD, 3RD), electric current is through double bladed knife swich 1HK ₂Or 2HK ₂Flow through, because two fuse connection D are whole section the most weak positions of fuse, so the fuse at D place, very fast fusing makes A.C. contactor JC or middle relay discharge because of outage, and normally opened contact resets, and forces motor out of service.If X ₁₂The phase failure, intermediate relay ZJ because of no current by being failure to actuate, A.C. contactor JC does not have electric current to pass through yet, its normally opened contact JC still remains stationary, the motor fail to start, when the power supply phase failure, the electric current in the control loop can not constitute the loop, intermediate relay ZJ or A.C. contactor JC are failure to actuate, and motor can't start.

Claims

1, a kind of threephase motor open phase protection is characterized in that double bladed knife swich 1HK in parallel separately on any two-phase main fuse of motor ₂, 2HK ₂Another is connected to intermediate relay ZJ, its normally opened contact ZJ1 links to each other with A.C. contactor JC, the contact of knife switch B side holder links to each other with stop button TA with intermediate relay ZJ respectively, the fuse of B side is connected on the A side fuse greater than its fusing point, and the line footpath that is connected fuse A side junction D is identical with the line footpath of B side fuse.