CN202651770U

CN202651770U - Motor phase loss protection circuit

Info

Publication number: CN202651770U
Application number: CN 201220352839
Authority: CN
Inventors: 李彬林
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-07-20
Filing date: 2012-07-20
Publication date: 2013-01-02
Anticipated expiration: 2022-07-20

Abstract

The utility model relates to a motor phase loss protection circuit, which comprises a three-phase power supply detection circuit, an optocoupler trigger circuit, a single-chip microcomputer control circuit and a drive circuit. Output signals of the three-phase power supply detection circuit are transmitted to the single-chip microcomputer control circuit through the optocoupler trigger circuit, and output signals of the single-chip microcomputer control circuit are transmitted to the drive circuit in a controlling manner. When phase loss occurs, no sensing voltage is output by a corresponding phase, an optocoupler is in a cutoff state, the drive circuit is started after judgment is made by a single-chip microcomputer, and the power supply of a motor is cut off. When heat is generated by the motor due to over heavy load, the working current of the motor increases, and when the working current exceeds a preset value, a thermal relay acts, the normally closed contact of the thermal relay is disconnected, the power of an alternating-current contactor is cut off for release, the power supply of the motor is cut off, and the motor is prevented from being damaged due to overload. The motor phase loss protection circuit has the advantages of simple circuit, low cost, easiness in manufacturing, stability and reliability in operation and no need for debugging, and is suitable for phase loss protection of medium-sized and small-sized three-phase alternating-current motors.

Description

A kind of motor phase failure protection circuit

Technical field

The utility model relates to a kind of protective circuit, particularly be a kind of motor phase failure protection circuit.

Background technology

Motor is because of the overweight adstante febre of load, and its operating current will increase, and motor will damage because of overload.

The utility model content

The purpose of this utility model is to overcome above-mentioned shortcoming, and a kind of motor phase failure protection circuit is provided.

The technical scheme that its technical problem that solves the utility model adopts is: a kind of motor phase failure protection circuit; comprise three phase mains testing circuit, optocoupler circuits for triggering, single chip machine controlling circuit and drive circuit; the output signal of described three phase mains testing circuit transfers to single chip machine controlling circuit through the optocoupler circuits for triggering, and the output signal control of described single chip machine controlling circuit is sent to drive circuit.

The current transformer that described three phase mains testing circuit is connected by three-phase power output end, and the bridge rectifier that the current transformer output connects consists of.

Described optocoupler circuits for triggering are made of its inner diode and triode.

By adopting above-mentioned technical scheme, the beneficial effects of the utility model are: when phase shortage occurs when, and corresponding mutually non-inductive voltage output, optocoupler is in cut-off state, judges back driving circuit through single-chip microcomputer, cuts off motor power; When motor because of the overweight adstante febre of load; its operating current will increase; when its operating current surpasses set point; thermal relay will move, and its normally-closed contact will disconnect, and the A.C. contactor outage is discharged; cut off the power supply of motor; prevent that motor from damaging because of overload, have that circuit is simple, cost is low, easy making, working stability are reliable, need not the characteristics such as debugging, are suitable for the open phase protection of middle-size and small-size three-phase alternating-current motor.

Description of drawings

Fig. 1 is frame assumption diagram of the present utility model;

Fig. 2 is circuit theory diagrams of the present utility model.

Embodiment

The utility model is described in further detail below in conjunction with accompanying drawing.

As shown in Figure 1 and Figure 2; a kind of motor phase failure protection circuit of the present utility model; comprise three phase mains testing circuit 1, optocoupler circuits for triggering 2, single chip machine controlling circuit 3 and drive circuit 4; the output signal of described three phase mains testing circuit 1 transfers to single chip machine controlling circuit 3 through optocoupler circuits for triggering 2, and the output signal control of described single chip machine controlling circuit 3 is sent to drive circuit 4.

The current transformer T1-T3 that described three phase mains testing circuit 1 is connected by three-phase power output end, and the bridge rectifier D1-D12 formation of current transformer output connection, described optocoupler circuits for triggering 2 are made of its inner diode and triode.

After the motor M running, to induce alternating voltage more than the 3V at the secondary side of current transformer T1-T3, this voltage is behind rectifier diode VD1～VD12 bridge rectifier, after the inner triode conducting of photoelectrical coupler U1-U3, the output low level signal, be connected to the 35th, 33,24 pin of single-chip microcomputer IC1, after single-chip microcomputer IC1 identification is judged, do not send control signal.

When certain reason makes in the three phase mains arbitrary disconnected mutually or after the phase shortage mutually; when if L2 breaks mutually; current transformer T2 does not have Voltage-output; photoelectrical coupler U2 inputs because of non-transformer; its inner triode is in cut-off state; the output high level, this signal is input to the 33rd pin of single-chip microcomputer IC1, after single-chip microcomputer IC1 internal processor is judged; the 4th pin output high level of single-chip microcomputer IC1; through resistance R 7 current limlitings, make transistor Q1 conducting, the relay J adhesive; its contact J-1 is also by transferring normally closed point normal battle to; A.C. contactor KM outage is discharged, cut off the power supply of doing of motor M, can not damage because of phase shortage with the protection motor.

When motor M because of the overweight adstante febre of load, its operating current will increase, when its operating current surpasses set point, thermal relay FR will move, and its normally-closed contact will disconnect, and A.C. contactor KM outage is discharged, cut off the power supply of doing of motor M, prevent that motor from damaging because of overload.

Above-described only is a preferred embodiment of the present utility model, can not limit the scope that the utility model is implemented, and every equalization of doing according to the utility model claim changes and decorates, and all should still belong in the scope that the utility model contains.

Claims

1. motor phase failure protection circuit; it is characterized in that: comprise three phase mains testing circuit (1), optocoupler circuits for triggering (2), single chip machine controlling circuit (3) and drive circuit (4); the output signal of described three phase mains testing circuit (1) transfers to single chip machine controlling circuit (3) through optocoupler circuits for triggering (2), and the output signal control of described single chip machine controlling circuit (3) is sent to drive circuit (4).

2. motor phase failure protection circuit according to claim 1 is characterized in that: the current transformer that described three phase mains testing circuit (1) is connected by three-phase power output end, and the bridge rectifier formation of current transformer output connection.

3. motor phase failure protection circuit according to claim 1 and 2, it is characterized in that: described optocoupler circuits for triggering (2) are made of its inner diode and triode.