Motor protection circuit of reciprocating motion device
By introducing a time relay into the motor control circuit, the problem of motor stalling caused by limit switch failure in the electric coal plow was solved, realizing active protection of the motor, avoiding damage and reducing production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HUAINAN MINING IND GRP
- Filing Date
- 2025-04-10
- Publication Date
- 2026-05-15
AI Technical Summary
In existing technologies, the limit switches of electric coal plows are prone to failure, leading to motor stalling, overheating, and burnout.
By introducing a time relay into the motor control circuit, an active protection mechanism is formed to prevent the motor from stalling for a long time, thus adding a layer of protection.
It effectively avoids motor damage, reduces emergency repairs, improves the safety factor of motor use, and saves production costs.
Smart Images
Figure CN224249348U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of power distribution control for coal-fired power plant equipment, and specifically relates to a protection circuit for a reciprocating motion device. Background Technology
[0002] Taking the electric coal plow as an example of a reciprocating device, it is widely used at the coal drop-off point of the raw coal bunker in power plant boilers as a unloading device for bulk materials on belt conveyors. Its basic working principle is to use the plow plate to form an arc-shaped coal retaining plate on the surface of the raw coal conveyor belt, and use the inertia of the raw coal on the moving belt to change the direction of movement of the raw coal scattered on the belt, so that it falls into the front bunker of the furnace.
[0003] The electric coal plow uses the forward and reverse rotation of the motor to control the raising or lowering of the coal baffle plate, thus achieving the coal plowing function. During normal use, when the coal plow is in the raised (or lowered) state, operating the lower (or raised) button activates the self-holding contactor circuit, continuously energizing the motor to rotate and lower (or raise) the coal baffle plate. Once the mechanical limit for lowering (or raising) is reached, the self-holding contactor circuit is disconnected, ending the lowering (or raising) action, and the coal plow is in a plowing (or suspended) state.
[0004] The current technology has the following drawbacks: During production, the coal plow is operated remotely. The mechanical lifting or lowering limit switches of the coal plow are prone to malfunction after prolonged and repeated use. If the limit switch fails to disconnect the self-holding contactor circuit after reaching the limit, and the thermal relay is unreliable, the motor will stall, leading to overheating and burnout. This phenomenon has occurred multiple times in actual production. Utility Model Content
[0005] The technical problem to be solved by this utility model is how to improve the safety factor of motor use and avoid motor stall operation, overheating and burning accidents.
[0006] This utility model solves the above-mentioned technical problems through the following technical solution:
[0007] This utility model provides a motor protection circuit for a reciprocating motion device, including a motor power supply main circuit and a motor control circuit. The motor power supply main circuit includes a three-phase power supply, a motor coil, a normally open main contact (2) for forward rotation of the motor, and a normally open main contact (1) for reverse rotation of the motor. The motor control circuit is connected in series with a normally closed contact ST (4) of a time relay and a normally closed contact RJ (5) of a thermal relay.
[0008] Furthermore, one end of the working voltage coil of the time relay (3) is connected to the N line, and the other end is connected to any power supply phase line of the motor.
[0009] Preferably, the time relay (3) is model JSZ3 AB.
[0010] Preferably, the motor control circuit includes a motor forward rotation control circuit, a motor reverse rotation control circuit, a motor forward rotation limit circuit, a motor reverse rotation limit circuit, a motor forward rotation permission indicator circuit, and a motor reverse rotation permission indicator circuit connected in parallel.
[0011] Preferably, the motor forward rotation control circuit includes a motor forward rotation start switch (91), a motor forward rotation programmable switch (101), and a motor forward rotation holding auxiliary normally open contact (111) connected in parallel. Its common terminal is connected in series with a motor reverse rotation interlock auxiliary normally closed contact (81), a motor forward rotation contactor (71), and a motor forward rotation limit auxiliary normally open contact (61).
[0012] The motor reversal control circuit includes a motor reversal start switch (92), a motor reversal programmable switch (102), and a motor reversal holding auxiliary normally open contact (112) connected in parallel. Its common terminal is connected in series with the motor forward rotation interlock auxiliary normally closed contact (82), the motor reversal contactor (72), and the motor reversal limit auxiliary normally open contact (62).
[0013] The common terminal of the normally open auxiliary contact (61) for forward rotation of the motor and the normally open auxiliary contact (62) for reverse rotation of the motor is connected to the normally closed contact RJ (5) of the thermal relay.
[0014] Preferably, the motor forward rotation limit circuit includes a motor forward rotation limit switch (141) and a motor forward rotation limit relay (121) connected in series.
[0015] The motor reversal limit circuit includes a motor reversal limit switch (142) and a motor reversal limit relay (122) connected in series.
[0016] Preferably, the motor forward rotation permission indicator circuit includes a motor forward rotation limit auxiliary normally open contact (61) and a motor forward rotation permission indicator (131) connected in series.
[0017] The motor reversal permission indicator circuit includes a normally open motor reversal limit auxiliary contact (62) and a motor reversal permission indicator (132) connected in series.
[0018] The advantages of this utility model are:
[0019] (1) This utility model achieves the passive protection of the thermal relay when the coal plow motor is stuck by adding a time relay, thus changing the passive protection of the thermal relay to the active protection of the time relay, adding a layer of protection and improving the safety factor of the motor.
[0020] (2) After the present invention is used, it can effectively prevent motor damage, avoid emergency repairs, reduce the labor intensity of personnel, and save production expenses.
[0021] (3) This utility model has been put into practical application and is widely used in coal plows or similar reciprocating motion devices. It has great promotional value and huge economic benefits. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the protection circuit of a reciprocating motion device according to the present invention;
[0023] Reference numerals: 1. Normally open main contact for motor reversal; 2. Normally open main contact for motor forward rotation; 3. Time relay; 4. Normally closed contact ST; 5. Normally closed contact RJ for thermal relay; 61. Normally open auxiliary contact for motor forward limit; 62. Normally open auxiliary contact for motor reverse limit; 71. Motor forward contactor; 72. Motor reverse contactor; 81. Normally closed auxiliary contact for motor reverse interlock; 82. Normally closed auxiliary contact for motor forward interlock; 91. Motor forward start switch; 92. Motor reverse start switch; 101. Motor forward programmable switch; 102. Motor reverse programmable switch; 111. Normally open auxiliary contact for motor forward holding; 112. Normally open auxiliary contact for motor reverse holding; 121. Motor forward limit relay; 122. Motor reverse limit relay; 131. Motor forward permission indicator light; 132. Motor reverse permission indicator light; 141. Motor forward limit switch; 142. Motor reverse limit switch. Detailed Implementation
[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below in conjunction with the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0025] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments:
[0026] Example 1
[0027] This embodiment provides a protection circuit for a reciprocating motion device, such as... Figure 1As shown, the system includes a main power supply circuit for the motor and a motor control circuit. The main power supply circuit includes a three-phase power supply, motor coils, and normally open main contacts 2 for forward rotation and 1 for reverse rotation. The motor control circuit connects a normally closed contact ST4 of a time relay and a normally closed contact RJ5 of a thermal relay in series. The normally open main contacts 2 for forward rotation and 1 for reverse rotation are used to adjust the phase sequence of any two phases supplying the motor coils, thus switching the motor between forward and reverse rotation; this is existing technology. The normally closed contact RJ5 of the thermal relay serves as a first layer of protection for the motor and is also existing technology, so it will not be elaborated upon here.
[0028] The operating voltage coil of the time relay 3 is connected at one end to the neutral (N) line and at the other end to any power supply phase line of the motor. The power supply of the time relay is synchronized with the power supply of the motor. When the motor loses power, the time relay 3 de-energizes and resets; when the motor is powered on, the time relay 3 is powered on and begins timing. In practical applications, the JSZ3 AB time relay 3 is recommended.
[0029] The motor control circuit includes a motor forward rotation control circuit, a motor reverse rotation control circuit, a motor forward rotation limit circuit, a motor reverse rotation limit circuit, a motor forward rotation permission indicator circuit, and a motor reverse rotation permission indicator circuit connected in parallel.
[0030] The motor forward rotation control circuit includes a motor forward rotation start switch 91, a motor forward rotation programmable switch 101 and a motor forward rotation holding auxiliary normally open contact 111 connected in parallel. Its common terminal is connected in series with a motor reverse rotation interlock auxiliary normally closed contact 81, a motor forward rotation contactor 71 and a motor forward rotation limit auxiliary normally open contact 61.
[0031] The motor reversal control circuit includes a motor reversal start switch 92, a motor reversal programmable switch 102, and a motor reversal holding auxiliary normally open contact 112 connected in parallel. Its common terminal is connected in series with a motor forward rotation interlock auxiliary normally closed contact 82, a motor reversal contactor 72, and a motor reversal limit auxiliary normally open contact 62.
[0032] The common terminal connecting the normally open auxiliary contact 61 for forward motor limit and the normally open auxiliary contact 62 for reverse motor limit is connected to the normally closed contact RJ5 of the thermal relay.
[0033] The motor forward rotation limit circuit includes a motor forward rotation limit switch 141 and a motor forward rotation limit relay 121 connected in series.
[0034] The motor reversal limit circuit includes a motor reversal limit switch 142 and a motor reversal limit relay 122 connected in series.
[0035] The motor forward rotation permission indicator circuit includes a normally open motor forward rotation limit auxiliary contact 61 and a motor forward rotation permission indicator 131 connected in series.
[0036] The motor reverse permission indicator circuit includes a normally open motor reverse limit auxiliary contact 62 and a motor reverse permission indicator 132 connected in series.
[0037] In this embodiment, the protection circuit of the provided reciprocating motion device operates as follows:
[0038] First, record the time of the one-way action of the coal plow lifting (or lowering) (the time for both lifting and lowering is the same). During normal use, if the coal plow is in the lifted state, after remotely issuing the command to lower the coal plow, the self-holding circuit for lowering the coal plow is activated, the motor is powered on and rotates, and the coal retainer plate falls. Timing begins at this point. When the mechanical limit for lowering is reached, the self-holding contactor circuit for lowering is disconnected, the coal retainer plate lowering action is completed, and the timing ends. Assuming the timing time is 10 seconds, the coal retainer plate is already in the coal plowing state. The time setting of time relay 3 must be greater than 10 seconds, for example, 15 seconds.
[0039] Taking the process of the coal plow's retaining plate being raised (motor forward rotation) as an example, when the retaining plate is in a non-limited position and the mains power is normally connected, the motor forward limit relay 121 and the motor reverse limit relay 122 are energized, and the motor forward limit auxiliary normally open contact 61 and the motor reverse limit auxiliary normally open contact 62 are closed. After pressing the motor forward start switch 91 or the remote operation motor forward programmable switch 101, the motor forward holding auxiliary normally open contact 111 is closed (at the same time, the motor forward interlock auxiliary normally closed contact 82 is opened, forming an interlock between the motor forward and reverse rotation), the motor forward contactor 71 is energized, the motor forward normally open main contact 2 is closed, and the motor is energized and rotates forward. The motor controls the coal baffle to lift. When the lifting mechanical limit is reached, the motor forward limit switch 141 opens, the motor forward limit relay 121 is de-energized, and the motor forward limit auxiliary normally open contact 61 opens (simultaneously, the motor forward permission indicator 131 is de-energized and goes out, indicating that the motor forward operation cannot be started at this time). The motor forward contactor 71 is de-energized, the motor forward normally open main contact 2 opens, the motor stops due to de-energization, and the lifting action ends. At this time, the time relay 3 resets due to de-energization, and the timing ends.
[0040] During the above process, if the motor forward limit switch 141 fails to disconnect, the motor power supply remains, and stall operation begins. At this time, time relay 3 continues to be energized after timing for at least 10 seconds. When the timing reaches 15 seconds, time relay 3 activates, the normally closed contact ST4 opens, the motor forward contactor 71 is de-energized, the normally open main contact 2 opens, the motor stops, the lifting action ends, and time relay 3 resets. Therefore, the stall duration is only about 5 seconds, with negligible impact on the motor. The process of the plow lowering the coal plow is the reverse, and will not be elaborated further.
[0041] The above process effectively prevents motor damage caused by prolonged stalling when the mechanical limit switch fails and the thermal relay is unreliable.
[0042] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.
Claims
1. A motor protection circuit for a reciprocating motion device, comprising a main power supply circuit for the motor and a motor control circuit, characterized in that, The main power supply circuit for the motor includes a three-phase power supply, a motor coil, a normally open main contact (2) for forward rotation of the motor, and a normally open main contact (1) for reverse rotation of the motor; the motor control circuit is connected in series with a normally closed contact ST (4) for a time relay and a normally closed contact RJ (5) for a thermal relay.
2. The motor protection circuit of the reciprocating motion device according to claim 1, characterized in that, The working voltage coil of the time relay (3) is connected to the N line at one end and to any power supply phase line of the motor at the other end.
3. The motor protection circuit of the reciprocating motion device according to claim 1, characterized in that, The time relay (3) is model JSZ3 AB.
4. The motor protection circuit of the reciprocating motion device according to claim 1, characterized in that, The motor control circuit includes a motor forward rotation control circuit, a motor reverse rotation control circuit, a motor forward rotation limit circuit, a motor reverse rotation limit circuit, a motor forward rotation permission indicator circuit, and a motor reverse rotation permission indicator circuit connected in parallel.
5. The motor protection circuit of the reciprocating motion device according to claim 4, characterized in that, The motor forward rotation control circuit includes a motor forward rotation start switch (91), a motor forward rotation programmable switch (101), and a motor forward rotation holding auxiliary normally open contact (111) connected in parallel. Its common terminal is connected in series with a motor reverse interlock auxiliary normally closed contact (81), a motor forward rotation contactor (71), and a motor forward rotation limit auxiliary normally open contact (61).
6. The motor protection circuit of the reciprocating motion device according to claim 4, characterized in that, The motor reversal control circuit includes a motor reversal start switch (92), a motor reversal programmable switch (102), and a motor reversal holding auxiliary normally open contact (112) connected in parallel. Its common terminal is connected in series with the motor forward rotation interlock auxiliary normally closed contact (82), the motor reversal contactor (72), and the motor reversal limit auxiliary normally open contact (62).
7. The motor protection circuit of the reciprocating motion device according to claim 6, characterized in that, The common terminal of the normally open auxiliary contact (61) for forward rotation of the motor and the normally open auxiliary contact (62) for reverse rotation of the motor is connected to the normally closed contact RJ (5) of the thermal relay.
8. The motor protection circuit of the reciprocating motion device according to claim 4, characterized in that, The motor forward rotation limit circuit includes a motor forward rotation limit switch (141) and a motor forward rotation limit relay (121) connected in series.
9. The motor protection circuit of the reciprocating motion device according to claim 4, characterized in that, The motor reversal limit circuit includes a motor reversal limit switch (142) and a motor reversal limit relay (122) connected in series.
10. The motor protection circuit of the reciprocating motion device according to claim 4, characterized in that, The motor forward rotation permission indicator circuit includes a normally open contact (61) for motor forward rotation limit auxiliary and a motor forward rotation permission indicator (131) connected in series. The motor reversal permission indicator circuit includes a normally open motor reversal limit auxiliary contact (62) and a motor reversal permission indicator (132) connected in series.