CN2241937Y

CN2241937Y - Full-protector for electric motor

Info

Publication number: CN2241937Y
Application number: CN 95238112
Authority: CN
Inventors: 李海泉
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-11-28
Filing date: 1995-11-28
Publication date: 1996-12-04
Anticipated expiration: 2005-11-28

Abstract

The utility model relates to a full-protector for an electric motor. A phase interruption protection circuit is that after three-phase voltage is sampled by three capacitors, is rectified, is stabilized voltage, is delayed, is stored energy, and is antijammed, a thyristor is triggered, and then a relay acts, so the power loop of an electric motorcontactor is cut off. An over-current and over-load protection circuit is that a simulation electrical motor wire or a thermoelement is connected in series in a two-phase power wire, and then a thermoswitch is also cut off the power hoop of the electric motor contactor. The utility model has the advantages of complete function, excellent performance, simple structure, low cost, and high safety.

Description

The motor protector

The utility model relates to a kind of emergency protective device of motor.

Motor is the core of transmission mechanism; in industrial and agricultural production and national defence; be widely used in the various facilities and equipments of scientific research; and motor is because main fuse fusing; reasons such as contacts of contactor scaling loss cause phase shortage and motor windings joint broken string; machinery is stuck; damage of bearings; reasons such as overtension cause overcurrent overheat and to burn out motor countless; thereby the external for example motor heat protector of Siemens production is just adopted widely motor is protected; this thermal protector is that thermistor is embedded in the motor stator winding; be connected to protector in the control cubicle by the dedicated transport line; domestic also the development utilized current transformer; voltage transformer sensing phase shortage; over-current signal; cut off motor power through amplifying circuit pusher motor type relay control contactor; above-mentioned technology has the certain protection effect to motor; but complex structure mostly; the production cost height; poor reliability; the former has increased the difficulty of motor technique for coiling, and is often given it up after the maintenance.

The purpose of the utility model aim to provide a kind of existing phase failure protection function, again have the over-current and-load defencive function, simple in structure, production cost is low, safe and reliable, installation and maintenance motor protector easily.

Technical solution of the present utility model is: this motor protector is by open-phase protection circuit; the over-current and-load protective circuit is formed; open-phase protection circuit is that the end with three electric capacity is connected to the three-phase power line that directly enters motor respectively; after the other end links together; by rectification; voltage stabilizing; the time-delay energy storage; anti-interferencely remove to trigger controllable silicon; relay line bag is serially connected in the silicon controlled sun cathode return circuit; the contact of relay then is serially connected in the line bag loop of motor contactor; the over-current and-load protective circuit is a simulated machine lead or thermal element to be serially connected in straight line enter in the two power supply phase lines of motor, and thermoswitch is serially connected in the motor contactor line bag loop.

The utility model is compared with prior art; owing to adopted the three phase capacitance voltage sampling; help improving electric network performance, sampling accurately and reliably; carry out voltage stabilizing; time-delay, anti-interference and triggering controllable silicon loop realize that open phase protection control is contactless, and reliability strengthens greatly; the over-current and-load protective circuit adopts simulated machine winding and temperature-sensitive element, thermoswitch, make that this protector is multiple functional, function admirable, reasonable in design, simple in structure, production cost is low, installation and maintenance are convenient.

Fig. 1 is the utility model circuit diagram.

Be described in further detail below in conjunction with the enforcement of accompanying drawing technical solutions of the utility model:

As shown in Figure 1, this motor protector is made up of open-phase protection circuit, over-current and-load protective circuit, and open-phase protection circuit is by electric capacity the three phase mains that motor directly enters to be carried out voltage sampling, and by its neutral tie point output, capacitor C ₁, C ₂, C ₃One end connects the three-phase power line that directly enters motor respectively, and the other end connects together, and becomes the neutral output point that connects, and is connected to rectifier (D ₁～D ₄) input, rectifier (D ₁～D ₄) another input be connected to zero-power line " R ", rectifier (D ₁～D ₄) two outputs be parallel with voltage-stabiliser tube WV ₁, capacitor C ₅, resistance R ₁And diode D ₅, resistance R ₂Back in parallel and capacitor C ₆Series circuit, rectifier (D ₁～D ₄) two outputs also be parallel with relay line bag (J ₁) with the series circuit of the positive negative electrode of controllable silicon (KG), diode D ₅With resistance R ₂Back in parallel and capacitor C ₆The connection mid point by voltage-stabiliser tube WV ₂After be connected to the trigger electrode of controllable silicon KG.The over-current and-load protective circuit is serially connected in the two power supply phase lines that directly enter motor by simulated machine lead or thermal element (RJ); thermoswitch RJ-1, the RJ-2 of simulated machine lead or thermal element (RJ) is connected in the line bag loop of motor contactor (1,2), and (1,2) also are in series with relay (J in the line bag loop of motor contactor ₁) normally-closed contact (J1-1), relay (J ₁) normally opened contact (J1-2) then be connected to contactor line bag loop (RJ-2) and capacitance voltage sampling mid point and be connected electric capacity (C in two ends ₄) on.Constitute automatic self-sustaining branch road.

Operation principle:

When the three phase mains balance operate as normal of motor, capacitor C ₁, C ₂, C ₃The connection mid point be output as 0, as lacking one mutually or two-phase power supply, capacitor C ₁, C ₂, C ₃The connection mid point produce voltage immediately, this voltage is through rectifier (D ₁～D ₄) after the rectification, the voltage of output certain value is through voltage-stabiliser tube WY1 voltage stabilizing, the anti-interference (C of time-delay energy storage ₅, R ₁, R ₂, C ₆) after, and by voltage stabilizing didoe WY ₂Remove triggering and conducting controllable silicon (KG), the conducting of controllable silicon (KG) makes the relay line bag (J that is connected on controllable silicon (KG) anode ₁) the acquisition operating current, relay (J ₁) adhesive, the A.C. contactor line bag electric power loop (1,2) that cuts off motor work, contactor discharges, and cuts off the motor three phase mains, obtains protection.The over-current and-load protective circuit then is that simulated machine lead or thermal element (RJ) are connected in the two power supply phase lines that directly enter motor; normal as operating current; lead or thermal element (RJ) can be not too many heating; as motor because the overload; machinery blocks; when reasons such as damage of bearings cause electric current to increase; lead or thermal element (RJ) heating; make the thermoswitch RJ-1 that is installed together; the RJ-2 tripping; and thermoswitch (RJ-1; RJ-2) be the line bag loop (1 that is connected on the motor contactor again; 2) in; thereby contactor line bag dead electricity; cut off motor power; the protection motor, Fig. 1 repeat circuit normally opened contact J1-2 passes through capacitor C ₄The back connects sampling capacitor C ₁, C ₂, C ₃Output connect mid point, this is a kind of relay (J ₁) automatic self-sustaining circuit, prevent relay and A.C. contactor frequent suction, put action, make this protector more automatic, reliable.

Claims

1, a kind of motor protector is characterized in that by open-phase protection circuit, and the over-current and-load protective circuit is formed, and open-phase protection circuit is with three electric capacity (C ₁, C ₂, C ₃) end is connected to the three-phase power line that directly enters motor respectively, after the other end links together, by rectification (D ₁～D ₄), voltage stabilizing (WV ₁), time-delay energy storage anti-interference (C ₅, R ₁, R ₂, C ₄) remove to trigger controllable silicon (KG), relay line bag (J ₁) be serially connected in the positive cathode return circuit of controllable silicon (KG); the contact of relay (J1-1) then is serially connected in the line bag loop (1,2) of motor contactor; the over-current and-load protective circuit is that a simulated machine lead or thermal element (RJ) are serially connected in two power lines that directly enter motor, and thermoswitch (RJ-1, RJ-2) also is serially connected in the motor contactor line bag loop (1,2).

2, motor protector according to claim 1, normally opened contact (J1-2) two ends that it is characterized in that relay are connected to contactor line bag loop (RJ-2) and are connected electric capacity (C with capacitance voltage sampling mid point ₄) on, constitute automatic self-sustaining branch road.