Power supply open-phase protection circuit

Abstract

The utility model discloses a power supply open-phase protection circuit which comprises a main loop and a control loop. The main loop comprises a power supply, a normally open contact of a circuit breaker QF, a normally open contact of a contactor KM and a motor M, one end of the normally open contact of the circuit breaker QF is connected with the power supply, and the other end of the normally open contact of the circuit breaker QF is connected with the motor M through the normally open contact of the contactor KM; the control loop comprises a first branch, a second branch, a third branch, a fourth branch and a fifth branch; under the action of the first branch circuit, the second branch circuit, the third branch circuit, the fourth branch circuit and the fifth branch circuit, the first indicator lamp HL1 and the second indicator lamp HL2 are utilized to monitor the open phase of the three-phase power supply, a specific abnormal phase is prompted to a maintainer, the working efficiency is improved, the cost of purchasing an open-phase protector is saved, and the circuit is more reliable through simple circuit transformation. Economic cost is low, effect is remarkable, practical value is high, and manpower and material resources are saved to the maximum extent.

Description

TECHNICAL FIELD

[0001] The utility model relates to circuit technical field, concretely relates to power supply open-phase protection circuit. BACKGROUND

[0002] The open-phase protector can effectively prevent three-phase short-circuit fault, in three-phase system, the current between any two phases exceeds the rated value, will lead to short-circuit fault, and the open-phase protector rapidly cuts off the power supply of fault phase when detecting abnormal current, thereby avoiding short-circuit fault further expansion, reducing the damage of equipment, and even possibly avoiding the occurrence of fire accident. When the system ground appears problem, will lead to the shell of equipment electrification, exists the risk of electric shock. And the open-phase protector can judge whether ground fault appears by monitoring the change of ground current, immediately cuts off the power supply of fault phase once detecting abnormality, guarantees personal safety.

[0003] The use frequency of open-phase protector in production enterprise is higher, and the damage rate is also higher, so certain economic cost is also brought. INVENTION CONTENTS

[0004] The utility model discloses a kind of power supply open-phase protection circuits.

[0005] The utility model is implemented by the following technical solutions: power supply open-phase protection circuit, characterized in that, it includes main circuit and control circuit;The main circuit includes power supply, the normally open contact of circuit breaker QF, the normally open contact of contactor KM, motor M, one end of the normally open contact of circuit breaker QF is connected with the power supply, the other end of the normally open contact of circuit breaker QF is connected with the motor M through the normally open contact of contactor KM;

[0006] The control circuit includes first branch, second branch, third branch, fourth branch and fifth branch;One end of the first branch is connected with the A phase of the power supply, the other end of the first branch is connected with N phase, and the first branch includes the coil of first intermediate relay KA1;One end of the second branch is connected with the B phase of the power supply, the other end of the second branch is connected with N phase, and the second branch includes the coil of second intermediate relay KA2;

[0007] One end of the third branch is connected with the C phase of the power supply, the other end of the third branch is connected with N phase, and the third branch includes the normally open contact of first intermediate relay KA1, the normally open contact of second intermediate relay KA2, first normally closed push-button switch SB1, second normally open push-button switch SB2 and the coil of contactor KM arranged in series, and the second normally open push-button switch SB2 is connected with the normally open contact of contactor KM in parallel.

[0008] The fourth branch is connected in parallel between the first normally closed push button switch SB1, the second normally open push button switch SB2 and the coil of the contactor KM of the third branch, and the fourth branch comprises a first indicator lamp HL1.

[0009] The fifth branch is connected in parallel between the normally open contact of the second intermediate relay KA2, the first normally closed push button switch SB1, the second normally open push button switch SB2 and the coil of the contactor KM of the third branch, and the fifth branch comprises a second indicator lamp HL2.

[0010] The utility model discloses the advantages are: under the action of first branch, second branch, third branch, fourth branch and fifth branch, utilize the action of first indicator lamp HL1 and second indicator lamp HL2, realize the monitoring of three -phase power lack phase, prompt the specific abnormal phase of maintenance personnel, improve the work efficiency, save the cost of purchase phase failure protector, through simple circuit transformation, and the economic cost is low, and the effect is remarkable, and the practical value is high, and the manpower and material resources are saved to the maximum. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical scheme in the embodiment of the utility model or prior art, the following will be briefly introduced to the drawing needed to be used in the embodiment or prior art description, obviously, the drawing in the following description only some embodiments of the utility model, for ordinary skilled person in the art, under the premise of not paying creative labor, still can obtain other drawings according to these drawings.

[0012] Figure 1 It is the circuit schematic diagram of the utility model;

[0013] In the drawing: main circuit 1, control circuit 2, circuit breaker QF, contactor KM, motor M, first branch 2.1, second branch 2.2, third branch 2.3, fourth branch 2.4, fifth branch 2.5, first intermediate relay KA1, second intermediate relay KA2, first normally closed push button switch SB1, second normally open push button switch SB2, first indicator lamp HL1, second indicator lamp HL2. DETAILED DESCRIPTION

[0014] The technical scheme in the embodiments of the utility model will be clearly and completely described in combination with the drawings in the embodiments of the utility model, and obviously, the described embodiments only some embodiments of the utility model, not all embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary skilled person in the art without creative labor belong to the scope of protection of the utility model.

[0015] As Figure 1The power phase failure protection circuit is shown, which includes a main circuit 1 and a control circuit 2; the main circuit 1 includes a power supply, a normally open contact of a circuit breaker QF, a normally open contact of a contactor KM, and a motor M; one end of the normally open contact of the circuit breaker QF is connected with the power supply, and the other end of the normally open contact of the circuit breaker QF is connected with the motor M through the normally open contact of the contactor KM;

[0016] The control circuit 2 includes a first branch 2.1, a second branch 2.2, a third branch 2.3, a fourth branch 2.4, and a fifth branch 2.5; one end of the first branch 2.1 is connected with an A phase of the power supply, and the other end of the first branch 2.1 is connected with an N phase; the first branch 2.1 includes a coil of a first intermediate relay KA1; one end of the second branch 2.2 is connected with a B phase of the power supply, and the other end of the second branch 2.2 is connected with the N phase; the second branch 2.2 includes a coil of a second intermediate relay KA2;

[0017] One end of the third branch 2.3 is connected with a C phase of the power supply, and the other end of the third branch 2.3 is connected with the N phase; the third branch 2.3 includes a normally open contact of the first intermediate relay KA1, a normally open contact of the second intermediate relay KA2, a first normally closed push button switch SB1, a second normally open push button switch SB2, and a coil of the contactor KM, which are sequentially connected in series; the second normally open push button switch SB2 is connected in parallel with a normally open contact of the contactor KM.

[0018] The fourth branch 2.4 is connected in parallel among the first normally closed push button switch SB1, the second normally open push button switch SB2, and the coil of the contactor KM of the third branch 2.3; the fourth branch 2.4 includes a first indicator lamp HL1.

[0019] The fifth branch 2.5 is connected in parallel among the normally open contact of the second intermediate relay KA2, the first normally closed push button switch SB1, the second normally open push button switch SB2, and the coil of the contactor KM of the third branch 2.3; the fifth branch 2.5 includes a second indicator lamp HL2.

[0020] The specific operation process of the embodiment is as follows:

[0021] The main circuit 1 is a conventional motor circuit;

[0022] In the main circuit 1, when the three-phase power supply is not phase failure, the switch of the circuit breaker QF is turned on, and the second normally open control button is pressed; at this time, the coil of the contactor KM is powered, the contactor KM is self-locked, and the motor M is normally operated;

[0023] In the control circuit 2, in the first branch 2.1, the coil of the first intermediate relay KA1 is electrified, in the second branch 2.2, the coil of the second intermediate relay KA2 is electrified, at this time, in the third branch 2.3, the normally open contact of the first intermediate relay KA1 is closed, the normally open contact of the second intermediate relay KA2 is closed, the first indicating lamp HL1 and the second indicating lamp HL2 are bright;

[0024] The second indicating lamp HL2 is bright, which indicates that the A phase and the C phase of the three-phase power supply are normal, the first indicating lamp HL1 is bright, which indicates that the B phase of the three-phase power supply is normal, and the first indicating lamp HL1 and the second indicating lamp HL2 are both bright, which indicates that the three-phase power supply is normal and has no phase shortage;

[0025] Because the control power is taken from the C phase, if the circuit breaker QF is closed, the second indicating lamp HL2 is not bright, the C phase power supply is checked first, if the C phase is normal, the A phase power supply is checked, if the second indicating lamp HL2 is bright and the first indicating lamp HL1 is not bright, it indicates that the B phase is short, at this time, the B phase of the three-phase power supply needs to be checked;

[0026] Under the actions of the first branch 2.1, the second branch 2.2, the third branch 2.3, the fourth branch 2.4 and the fifth branch 2.5, and under the actions of the first indicating lamp HL1 and the second indicating lamp HL2, the monitoring of the phase shortage of the three-phase power supply is realized, the specific abnormal phase is prompted to the maintenance personnel, the work efficiency is improved, the cost of purchasing the phase shortage protector is saved, through the simple circuit modification, the economic cost is low, the effect is remarkable, the practical value is high, and the manpower and material resources are saved to the maximum extent.

[0027] The above only describes the preferred embodiments of the utility model, and does not limit the utility model, any modification, equivalent replacement, improvement, etc. within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A power phase loss protection circuit, characterized by, It includes main circuit and control circuit, the main circuit includes power supply, the normally open contact of circuit breaker QF, the normally open contact of contactor KM, motor M, one end of the normally open contact of circuit breaker QF is connected with the power supply, the other end of the normally open contact of circuit breaker QF is connected with the motor M through the normally open contact of contactor KM; The control circuit includes first branch, second branch, third branch, fourth branch and fifth branch, one end of the first branch is connected with the A phase of the power supply, the other end of the first branch is connected with N phase, and the first branch includes the coil of first intermediate relay KA1;One end of the second branch is connected with the B phase of the power supply, and the other end of the second branch is connected with N phase, and the second branch includes the coil of second intermediate relay KA2; One end of the third branch is connected with the C phase of the power supply, and the other end of the third branch is connected with N phase, and the third branch includes the normally open contact of first intermediate relay KA1, the normally open contact of second intermediate relay KA2, first normally closed push-button switch SB1, second normally open push-button switch SB2 and the coil of contactor KM arranged in series, and the second normally open push-button switch SB2 is connected with the normally open contact of contactor KM in parallel. The fourth branch is connected in parallel between the first normally closed push-button switch SB1, the second normally open push-button switch SB2 and the coil of contactor KM of the third branch, and the fourth branch includes first indicating lamp HL1. The fifth branch is connected in parallel between the normally open contact of second intermediate relay KA2, the first normally closed push-button switch SB1, the second normally open push-button switch SB2 and the coil of contactor KM of the third branch, and the fifth branch includes second indicating lamp HL2.

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