CN2150655Y

CN2150655Y - Safety protecting instrument for AC motor

Info

Publication number: CN2150655Y
Application number: CN 93238531
Authority: CN
Inventors: 李本序
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-04-16
Filing date: 1993-04-16
Publication date: 1993-12-22
Anticipated expiration: 2003-04-16

Abstract

The utility model relates to a phase-failure, phase-absent safety protecting instrument for motors, which comprises current mutual inductors B1-B3 connected to a main circuit of a motor. A control circuit and a power supply circuit are connected with the motor circuit; a rectifying voltage stabilizing circuit, a time delay circuit and switch tubes BG1-BG3 mutually connected in series are respectively connected with B1-B3; a BG4 is connected to the BG1 to control the open and closure of a normally-closed relay J. The utility model has the advantages of simple structure, convenient use, safety, reliability, wide range of application, etc.

Description

Safety protecting instrument for AC motor

The utility model relates to a kind of protective device of motor, the particularly motor phase failure, the safeguard protection instrument of phase shortage.

Current; alternating current motor is often because of phase shortage; the phase failure and burning; a kind of alternating current motor multi-function protector is disclosed in Chinese patent CN2076723U; its feature is a Current Transformer sampling motor main circuit current signal size; sampled signal is through shaping circuit; rectification circuit; balance is adjusted circuit; waveform integer circuit; delay circuit; be input to the input and the relatively back output of reference voltage of high accuracy disjunction gate voltage comparator; be used for the break-make of control circuit; thereby the realization phase failure; overload; under-voltage protection; its weak point is: complex structure; the cost height, the need accurate adjustment balance during use is adjusted circuit, uses complicated; and halfwave rectifier ripple coefficient high noise immunity is poor; poor stability, and the circuit parameter of having relatively high expectations could realize above-mentioned purpose, thereby also improved the product cost.

The purpose of this utility model designs a kind of simple in structure exactly, and cost is low, and is easy to use, and strong interference immunity, technological parameter require the low alternating current motor safeguard protection instrument that is suitable for all kinds of big small size motors.

The purpose of this utility model realizes by following structure: alternating current motor safeguard protection instrument includes the current transformer B that is connected on the motor main circuit ₁, B ₂, B ₃, its principal character is: be connected to control circuit and power circuit on motor circuit, at current transformer B ₁～B ₃On be connected to full-wave rectification voltage stabilizing circuit and RC delay circuit respectively, switching tube BG ₁～BG ₃, BG wherein ₁～BG ₃Series connection mutually is at BG ₁Output be connected to switching tube BG ₄, at BG ₄Output be connected to normally closed relay J in the control circuit, energized when using the utility model, control circuit work makes power circuit output 24V, BG ₄Work, relay J disconnects, and presses the start button of motor, the A.C. contactor work in the control circuit, machine operation, B simultaneously ₁～B ₃Take out the three-phase sampled signal in motor circuit, this sampled signal makes switching tube BG through regulator rectifier circuit and RC delay circuit ₁～BG ₃Work, BG ₄End, J is normally closed, unclamps start button, electric motor normal working, and when the phase failure of motor phase, phase shortage, BG ₁～BG ₃In a certain switching tube disconnect BG ₄Work, J disconnects, and motor quits work, thereby realizes electric motor protecting.

The utility model compared with prior art has following advantage:

1. simple in structure, manufacture craft is simple, and production cost is low.

2. easy to use, owing to adopt the switching tube cascaded structure, do not need to do any balance adjustment, just can realize the phase failure, the phase shortage safeguard protection of motor.

3. circuit technology parameter request of the present utility model is not high, thereby the easier manufacturing, and can realize the phase failure, phase shortage safeguard protection to all kinds of large and small different motor.

4. owing to adopt the full-wave rectification voltage stabilizing circuit, thereby low, the strong interference immunity of circuit ripple coefficient, safe.

Description of drawings of the present utility model is as follows:

Fig. 1 is a circuit structure diagram of the present utility model;

Among the figure: 1 control circuit, 2 power circuits, 3 full-wave rectification voltage stabilizing circuits, 4 delay circuits.

The utility model is described in further detail below in conjunction with drawings and Examples:

As shown in Figure 1: the utility model includes the current transformer B that is connected on the motor main circuit ₁, B ₂, B ₃, on motor circuit, be connected to full-wave rectification voltage stabilizing circuit 3 and RC delay circuit 4, switching tube BG ₁～BG ₃, BG wherein ₁～BG ₃Mutually series connection is connected to the switching tube BG that communicates with power circuit at the output of tandem tap pipe ₄, at BG ₄Output is connected to the normally closed relay J in the control circuit; Control circuit includes A.C. contactor CJ, often opens, normally closed start button QA, TA, and relay J and CJ ₂Power circuit is by capacitor C ₁With rectifier diode D ₁₄, D ₁₅And clamper voltage-stabiliser tube W ₄And capacitor C ₂, C ₃Constitute, the full-wave rectification voltage stabilizing circuit is to be made of diode bridge full-wave rectifying circuit and voltage-stabiliser tube W clamper; The utility model can be done the phase shortage safeguard protection to all types of big or small alternating current motors, reliability 100%.

Claims

1, a kind of alternating current motor safeguard protection instrument includes the current transformer B that is connected on the motor main circuit ₁, B ₂, B ₃, it is characterized in that: on motor circuit, be connected to control circuit and power circuit, at current transformer B ₁, B ₂, B ₃On be connected to full-wave rectification voltage stabilizing circuit and RC delay circuit respectively, switching tube BG ₁, BG ₂, BG ₃, BG wherein ₁, BG ₂, BG ₃Series connection mutually is at BG ₁Output be connected to the switching tube BG that communicates with power circuit ₄, at BG ₄Output is connected to the normally closed relay J in the control circuit.

2, alternating current motor safeguard protection instrument as claimed in claim 1, it is characterized in that: control circuit includes A.C. contactor J, often open, normally closed start button QA, TA, and relay J and CJ ₂

3, alternating current motor safeguard protection instrument as claimed in claim 1, it is characterized in that: power circuit is by capacitor C ₁With rectifier diode D ₁₄, D ₁₅And clamper voltage-stabiliser tube W ₄And capacitor C ₂, C ₃Constitute.

4, alternating current motor safeguard protection instrument as claimed in claim 1 is characterized in that: the full-wave rectification voltage stabilizing circuit is to be made of diode bridge full-wave rectifying circuit and voltage-stabiliser tube W.