CN201956946U - Motor auto voltage reducing starter box - Google Patents

Abstract

The utility model relates to a decompression starting device, in particular to a motor self-coupling decompression starting box. The main circuit includes a main motor auto-coupling decompression starting circuit and a motor operation mode switching control circuit. The input terminals of the motor auto-coupling decompression starting circuit are respectively used to connect the power supply of the three-phase AC motor, and the input terminals of the motor operation mode switching control circuit are used to be connected in series between the U phase and the W phase of the three-phase AC motor power supply . This device can ensure that the motor exits the autotransformer in time after the decompression autostart, and automatically changes to full voltage operation, thus effectively avoiding the autocoil TM from being burned due to long-term electrification.

Description

A motor self-coupling decompression starter box

technical field

The utility model relates to a decompression starting device, in particular to a motor self-coupling decompression starting box.

Background technique

For a long time, the three-phase motors in industrial and mining enterprises have widely used auto-coupling decompression starting boxes for decompression starting and full-voltage operation. Such starting can fully reduce the excessive starting current, reduce the impact on the motor and the power system, and realize electrical Safe and reliable operation of equipment. However, although the traditional auto-coupling decompression starting box can better realize the control functions such as decompression starting and overload protection of the motor, there are still some problems in actual use, and it is prone to failure. The main problems are as follows : (1) Human error when switching modes manually. The traditional starting box is equipped with a "manual/automatic" switching switch. When the manual switching method is adopted, due to the negligence of the operator, after the decompression starting is completed, the "Run" button cannot be pressed in time to switch to the full-pressure operation. The autotransformer passes the motor running current for a long time, causing it to burn out; (2) The device is damaged during the automatic switching mode. When using the automatic switching mode, due to the damage of some electrical components of the control circuit, such as the failure of the time relay, after the decompression start is completed, the secondary circuit cannot operate normally, so it cannot be switched to full-voltage operation in time. The autotransformer cannot be withdrawn, and it will burn out due to long-term load current; (3) The electrical components of the primary circuit are damaged. When the electrical components of the primary circuit, such as the starting contactor, etc. are damaged, after the start is completed, although the secondary circuit can operate normally (in most cases, because the auxiliary contact is not reset, the normal operation of the secondary circuit is locked) so that the The coil of the contactor is de-energized, but it cannot be released normally after power-off, that is, its contacts are severely burnt and cause sticking.

Utility model content

The purpose of the utility model is to provide a motor auto-coupling decompression starting box with high operational reliability and simple operation.

A motor auto-coupling decompression starting box, including a motor auto-coupling decompression starting circuit, a motor operation mode switching control circuit, the input terminals of the motor auto-coupling decompression starting circuit are respectively used to connect the power supply of a three-phase AC motor, and the motor runs The input terminal of the mode switching control circuit is used to be connected in series between the U phase and the W phase of the power supply of the three-phase AC motor. The motor operation mode switching control circuit is connected to the motor auto-coupling decompression starting circuit. The circuit includes a first contactor, a second contactor, a first relay, a second relay, a third relay, a first time relay, a second time relay, the coil of the first contactor, the normally open contact of the third relay point, the normally closed contact of the second relay is connected in series between the U phase line and the W phase line of the three-phase AC motor power supply, and the normally open contact of the first contactor and the coil of the second time relay are connected in parallel At the two ends of the coil of the first contactor; after the coil of the third relay and the energization delay disconnection switch of the second time relay are connected in series, they are connected in parallel between the coil of the first contactor and the normally open contact series circuit of the third relay. end, and the coil of the third relay is connected to the coil of the second time relay; the normally open contact of the first contactor and the coil of the first relay are connected in series to the U phase line and W phase of the three-phase AC motor power supply Between the wires, the normally open contacts of the first relay are connected in parallel at both ends of the normally open contacts of the first contactor; the normally open contacts of the first relay, the normally closed contacts of the second contactor, and the The coil is connected in series between the U phase and W phase of the power supply of the three-phase AC motor. Point and the two ends of the series circuit of the first time relay coil, the normally open contact of the second relay, the normally closed contact of the first contactor, and the coil of the second contactor are connected in series, and connected in parallel when the first time relay is energized The two ends of the delay closing switch and the second relay coil series circuit; after the parallel connection of the energization delay closing contact of the second time relay and the normally open contact of the second relay, they are connected in parallel to the energization delay closing contact of the first time relay At both ends of the point, the three linkage normally open contacts of the second contactor are respectively connected in series on the power supply of the three-phase AC motor; Transformer, the three linked normally open contacts of the first contactor are connected in series between the power supply of the three-phase AC motor and the tap coil of the auto-decompression transformer; the three-phase signal drawn from the middle tap of the auto-decompression transformer The output terminal of V phase is directly connected to the V phase of the power supply of the three-phase AC motor, and the output terminals of U phase and W phase are respectively connected in series with the two normally open contacts of the first contactor, and then connected to the three On the U phase and W phase of the power supply of the phase AC motor.

The motor operation mode switching control circuit also includes an auto-coupling decompression start indicating unit, and the auto-coupling decompression starting indicating unit includes a normally closed contact of the first relay, a green indicator light, a normally open contact of the first relay, a second The normally closed contact of the contactor, the yellow indicator light, the normally open contact of the second contactor, and the red indicator light, the normally closed contact of the first relay, and the green indicator light are connected in series to the three-phase AC motor power supply Between the U-phase line and the W-phase line, after the normally open contact of the first relay, the normally closed contact of the second contactor, and the yellow indicator light are connected in series, they are connected to the normally open contact of the first relay, the second The normally closed contact of the second contactor and the two ends of the yellow indicator light series circuit, after the normally open contact of the second contactor and the red indicator light are connected in series, are connected to the normally open contact of the first relay, the second The normally closed contact of the contactor and the two ends of the yellow indicator light series circuit.

The motor operation mode switching control circuit of the motor is also provided with a third normally open switch, which is connected in parallel to both ends of the energization delay closing contact of the first time relay.

The motor auto-coupling decompression starting box also includes a protection circuit, and the protection circuit includes U, V, W three-phase current detection units, and the circuits of the U, V, W three-phase current detection units are the same, and all include current The normally open contacts of transformers, thermal relays, and second relays. The normally open contacts of the thermal relay are connected in parallel at both ends of the thermal relay.

A current display is connected in series with the U-phase current transformer circuit in the auto-coupling decompression starting protection circuit of the motor.

Adopting the above technical scheme can achieve the following technical effects:

Since the utility model adopts the three linkage normally open contacts of the first relay and the three linkage normally open contacts of the second relay to control the auto-coupling decompression starting and full-voltage operation of the motor, as long as the start button is pressed, the motor will Automatic self-coupling decompression start, when the set time is reached, it will automatically switch to full-pressure operation, no need to manually switch, higher reliability, and easier operation.

Description of drawings

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

Fig. 2 is a schematic circuit diagram of the motor operating mode switching control circuit of the utility model.

Detailed ways

As shown in Figure 1: the utility model includes a motor operation mode switching control circuit, a motor auto-coupling decompression starting circuit, and the input terminals of the motor operation mode switching control circuit are respectively used to connect the U phase and the power supply of the three-phase AC motor M Phase W, the three-phase input terminals of the motor auto-decompression starting circuit are respectively used to connect the power supply of the three-phase AC motor M, and the motor operation mode switching control circuit controls the auto-coupling decompression starting circuit.

As shown in Figure 2: the motor operation mode switching control circuit includes a first contactor 1KM, a second contactor 2KM, a first relay 1KA, a second relay 2KA, a third relay 3KA, a first time relay 1KT, a second Time relay 2KT.

Among them, after the coil of the first contactor 1KM, the normally open contact 3KA1 of the third relay 3KA, and the normally closed contact 2KA4 of the second relay 2KA are connected in series, they are connected to the U phase line and the W of the power supply of the three-phase AC motor M Between the phase lines; the normally open contact 1KM4 of the first contactor 1KM is connected in series with the coil of the second time relay 2KT, and connected to both ends of the series circuit of the second normally open switch 2SB and the coil of the first contactor 1KM; After the coil of the third relay 3KA and the on-off delay contact 2KT1 of the second time relay 2KT are connected in series, they are connected in parallel to the coil of the first contactor 1KM and the two of the series circuit of the normally open contact 3KA1 of the third relay 3KA. terminal, and the coil of the third relay 3KA and the coil of the second time relay 2KT are also connected in parallel.

After the normally open contact 1KM5 of the first contactor 1KM is connected in series with the coil of the first relay 1KA, it is connected between the U phase line and the W phase line of the power supply of the three-wire AC motor M, and the normally open contact 1KA3 of the first relay 1KA Connect in parallel to both ends of the normally open contact 1KM4 of the first contactor 1KM.

The normally open contact 1KA4 of the first relay 1KA, the normally closed contact 2KM4 of the second contactor 2KM, and the coil of the first time relay 1KT are connected in series between the U phase line and the W phase line of the power supply of the three-phase AC motor M Between, after the energization delay closing contact 1KT1 of the first time relay 1KT, the coil of the second relay 2KA are connected in series, they are connected in parallel to the two ends of the series circuit of the normally closed switch 2KM4 of the second contactor 2KM and the coil of the first time relay 1KT; The normally open contact 2KA6 of the second relay 2KA, the normally closed contact 1KM6 of the first contactor 1KM, and the coil of the second contactor 2KM are connected in parallel to the normally closed switch 2KM4 of the second contactor 2KM and the first time relay The two ends of the 1KT coil series circuit; the energization delay closing contact 2KT2 of the second time relay 2KT, and the normally open contact 2KA5 of the second relay 2KA are respectively connected in parallel to the two energization delay closing contacts 1KT1 of the first time relay 1KT end.

The motor auto-decompression starting circuit includes a first contactor and an auto-decompression transformer TM. The three linkage normally open contacts 1KM1 of the first contactor 1KM are connected in series between the power supply of the three-phase AC motor M and the tap coil of the auto-decompression transformer TM; from the tap coil of the auto-decompression transformer TM 60% The three-phase signal line drawn out, wherein the V phase is directly connected to the V phase of the three-phase AC motor M power supply, and the U phase and W phase are respectively connected in series with the two normally open contacts 1KM3 and 1KM2 of the first contactor 1KM On the U phase and W phase of the power supply of the three-phase AC motor M.

The motor operation mode switching control circuit also includes a motor auto-coupling decompression start instruction unit. The motor auto-coupling decompression starting indication unit includes the normally closed contact 1KA1 of the first relay 1KA, the green indicator light HG, the normally open contact 1KA2 of the first relay 1KA, the normally closed contact 2KM2 of the second contactor 2KM, and the yellow indicator The light HY, the normally open contact 2KM3 of the second contactor 2KM, the red indicator HR, the normally closed contact 1KA1 of the first relay 1KA and the green indicator HG are connected in series to the U-phase line of the power supply of the three-phase AC motor M and Between the W phase lines; the normally open contact of the first relay 1KA, the normally closed contact 2KM2 of the second contactor 2KM, and the yellow indicator light HY are connected in parallel to the normally closed contact 1KA1 of the first relay 1KA and the green indicator The two ends of the series circuit of the lamp HG; after the normally open contact 2KM3 of the second contactor 2KM is connected in series with the red indicator HR, they are connected in parallel at both ends of the series circuit of the normally closed contact 1KA1 of the first relay 1KA and the green indicator HG.

An alarm circuit is also installed in the motor auto-coupling decompression starting indicating unit, and the alarm circuit includes a resistor R and an alarm DF, and the series circuit of the resistor R and the alarm DF is connected in parallel at both ends of the yellow indicator light HY.

Fuses FU1 and FU2 are provided on the U-phase line and W-phase line of the motor operation mode switching control circuit.

In addition, a first normally closed switch 1SB, a second normally open switch 2SB, a third normally open switch 3SB, and a normally closed contact FR1 of the thermal relay FR are also provided in the motor operation mode switching control circuit. The first normally closed switch 1SB and the normally closed contact FR1 of the thermal relay FR are respectively connected in series with the U phase line and the W phase line of the power supply of the three-phase AC motor M, the third normally open switch 3SB, and the third normally open switch 3SB. The open switch 3SB is connected in parallel with both ends of the energization delay closing contact 1KT1 of the first time relay 1KT.

The utility model also includes a protection circuit. The protection circuit includes a current detection unit of a three-phase power supply, and the U-phase current detection unit includes a current transformer LHu, a first thermal relay 1FR, a current display PA1, a normally closed contact 2KA1 of a second relay 2KA, and a U-phase current transformer. LHu is set on the U-phase line of the power supply of the three-phase AC motor M, the two output terminals of the U-phase current transformer LHu, one end is directly grounded, the other end is connected in series with the first thermal relay 1FR and the current display PA1 and then grounded, the second relay The normally closed contact 2KA1 of 2KA is connected in parallel at both ends of the first thermal relay 1FR; the V-phase current detection unit includes a current transformer LHv, the second thermal relay 2FR, the normally closed contact 2KA2 of the second relay 2KA, and the V-phase current mutual inductance The transformer LHv is set on the V-phase line of the power supply of the three-phase AC motor M. The two output ends of the V-phase current transformer LHv are directly grounded, and the other end is connected in series with the second thermal relay 2FR and then grounded. The normal of the second relay 2KA The closed contact 2KA2 is connected in parallel at both ends of the second thermal relay 2FR; the W-phase current detection unit includes the current transformer LHw, the third thermal relay 3FR, the normally closed contact 2KA3 of the second relay 2KA, and the W-phase current transformer LHw is set On the W-phase line of the three-phase AC motor M power supply, the two output terminals of the W-phase current transformer LHw, one end is directly grounded, the other end is connected in series with the third thermal relay 3FR and then grounded, and the normally closed contact of the second relay 2KA 2KA3 is connected in parallel at both ends of the third thermal relay 3FR;

The working process is as follows: when the main switch QS is closed, the green indicator light HG in the starting indication circuit in the electrical control circuit of the motor auto-coupling decompression starting box is on. Close the second switch 2SB (the second normally open switch 2SB is a light touch off button, when it is pressed down, it will be connected, and it will be disconnected after it is released), the coil of the third relay 3KA is energized, and its normally open contact The connection of point 3KA1 energizes the coil of the first contactor 1KM and the coil of the second time relay 2KT, and the three linkage normally open contacts 1KM1 of the first contactor 1KM pull in, and at the same time the two contacts of the first contactor 1KM The normally open contacts 1KM2 and 1KM3 are also attracted, so that the 380V power supply is drawn out through the 60% tap of the auto-decompression transformer, and added to the motor, so that the motor starts under the decompression state. The normally open contact 1KM5 of the first contactor 1KM pulls in and connects the coil of the first relay 1KA, so that the coil of the first relay 1KA is energized, and the normally open contacts 1KA2, 1KA3, and 1KA4 of the first relay 1KA are connected. The normally closed contact 1KA1 of the first relay 1KA is opened. The pull-in of the normally open contact 1KA2 of the first relay 1KA turns on the yellow indicator light HY; the pull-in of the normally open contact 1KA3 of the first relay 1KA keeps the coil of the first relay 1KA always in the energized state; the first relay The pull-in of 1KA normally open contact 1KA4 makes the first time relay 1KT coil energized and enters the timing state.

When the first time relay 1KT reaches the setting time, the auto-coupling decompression start of the motor is completed. The specific process is: the energization of the 1KT coil of the first time relay makes the energization delay closing contact 1KT1 of the first time relay 1KT delayed to be connected, so that the coil of the second relay 2KA is energized, and the normally open contact of the second relay 2KA 2KA5 and 2KA6 are pulled in, and the normally closed contact 2KA4 of the second relay 2KA is disconnected. The normally open contact 2KA5 of the second relay 2KA is pulled in so that the coil of the second relay 2KA remains energized; and the normally closed contact 2KA4 of the second relay 2KA is disconnected, so that the coil of the first contactor 1KM is de-energized. The normally open contacts of the first contactor 1KM are all disconnected, and all the normally closed contacts of the first contactor 1KM are restored to the closed state. In this way, due to the connection of the normally closed contact 1KM6 of the first contactor 1KM, the coil of the second contactor 2KM is energized, and the three linkage normally open main contacts 2KM1 of the second contactor 2KM are connected, and the three-phase AC motor M is transferred to 380V full voltage operation. Simultaneously, the normally open contact 2KM3 of the second contactor 2KM also pulls in, turning on the red indicator light HR.

In addition, after the second normally open switch 2SB is pressed, the coil of the second time relay 2KT is energized and enters the delay timing state, and its delay value is artificially set to be greater than the delay value of the first time relay 1KT, thus maintaining After the energization delay closing contact 1KT1 of the first time relay 1KT acts first, the second time relay 2KT is also cut off because of the power supply, without delay action. But when the first time relay 1KT fails and cannot operate within the set time to make the motor run at full voltage, after the delay reaches the set value of the second time relay 2KT, the power-on delay of the second time relay 2KT is closed The contact 2KT1 acts to cause the coil of the third relay 3KA to lose power, and then cut off the coil of the first contactor 1KM, so that the normally closed contact 1KM6 of the first contactor 1KM is closed. Then, the coil of the second relay 2KA is turned on through the energization delay closing contact 2KT2 of the second time relay 2KT, so that the normally open contact 2KA6 of the second relay 2KA is closed. Since the normally closed contact 1KM6 of the first contactor 1KM and the normally open contact 2KA6 of the second relay 2KA are both closed, the coil of the second contactor 2KM is energized, and the three linkage normally open contacts of the second contactor 2KM The point 2KM1 is closed, so that the autotransformer can reliably exit within the setting time of the second time relay 2KT, and the motor is turned from the starting state to the running state.

Of course, sometimes the time-delay moving contact of the second time relay 2KT itself may not be able to pull in time. At this time, although the circuit cannot be turned into the running state in time, it can ensure that the third relay 3KA is disconnected in time, so that the automatic Coupling coil TM can be withdrawn in time and reliably. In addition, when the second relay 2KA fails, it can ensure that the first contactor 1KM is powered off and disconnected from the autotransformer in time, thus effectively preventing the autocoil TM from being burned due to long-term electrification.

Claims (5)

1. motor self-decoupling decompressioning starting box, comprise motor self-coupling decompression starting circuit, motor operational mode control switching circuit, the input of motor self-coupling decompression starting circuit is respectively applied for the power supply that connects three phase alternating current motor, the input of motor operational mode control switching circuit is used to be concatenated between the U phase and W phase of three phase alternating current motor power supply, motor operational mode control switching circuit control connection motor self-coupling decompression starting circuit, it is characterized in that: described motor operational mode control switching circuit comprises first contactor, second contactor, first relay, second relay, the 3rd relay, very first time relay, second time relay, the coil of described first contactor, the normally opened contact of the 3rd relay, the normally-closed contact series connection of second relay is between the U of three phase alternating current motor power supply phase line and W phase line, the normally opened contact of first contactor, after the coil series connection of second time relay, be connected in parallel on the two ends of first contactor coil; After the on-delay cut-off switch series connection of the coil of the 3rd relay, second time relay, and be connected in the two ends of first contactor coil and the 3rd relay normally open contact series circuit, and the also coil of the coil of the 3rd relay and second time relay is connected; The coil series connection of the normally opened contact of first contactor, first relay is between the U of three phase alternating current motor power supply phase line and W phase line, and the normally opened contact of first relay is connected in parallel on the two ends of the first contactor normally opened contact; The normally opened contact of first relay, the normally-closed contact of second contactor, the coil series connection of very first time relay is between the U of three phase alternating current motor power supply phase and W phase, the on-delay closing contact of very first time relay, after the coil series connection of second relay, and be connected in the two ends of the series circuit of the normally-closed contact of second contactor and very first time relay coil, the normally opened contact of second relay, the normally-closed contact of first contactor, after the series connection of the coil of second contactor, and be connected in the two ends of the very first time relay power timing closing switch and the second relay coil series circuit; After the parallel connection of the on-delay closing contact of second time relay, the normally opened contact of second relay, be parallel to the two ends of very first time relay power timing closing contact, three interlock normally opened contacts of described second contactor are connected on respectively on the power supply of three phase alternating current motor; Described motor self-coupling decompression starting circuit comprises first contactor, self-coupling decompression transformer, and three of first contactor interlock normally opened contacts are serially connected between the tapped coil of the power supply of three phase alternating current motor and self-coupling decompression transformer; The three-phase signal line of drawing from the centre tap of self-coupling decompression transformer, wherein the output of the V phase V that is directly connected to the power supply of three phase alternating current motor goes up mutually, U mutually and W output mutually respectively with after two normally opened contacts of first contactor are connected, the U phase that is connected to the power supply of three phase alternating current motor goes up mutually with W.

2. motor self-decoupling decompressioning starting box as claimed in claim 1, it is characterized in that: described motor operational mode control switching circuit also comprises the self-coupling decompression starting indicating member, the self-coupling decompression starting indicating member comprises the normally-closed contact of first relay, green indicating lamp, the normally opened contact of first relay, the normally-closed contact of second contactor, yellow indicator lamp, the normally opened contact of second contactor, red led, the normally-closed contact of described first relay, the green indicating lamp series connection is received between the U phase line and W phase line of three phase alternating current motor power supply, the normally opened contact of described first relay, the normally-closed contact of second contactor, after the yellow indicator lamp series connection, and be connected to the normally opened contact of first relay, the normally-closed contact of second contactor, the two ends of yellow indicator lamp series circuit, the normally opened contact of described second contactor, after the red led series connection, and be connected to the normally opened contact of first relay, the normally-closed contact of second contactor, the two ends of yellow indicator lamp series circuit.

3. motor self-decoupling decompressioning starting box as claimed in claim 2 is characterized in that: described motor motor operational mode control switching circuit also is provided with the 3rd normal open switch, and the 3rd normal open switch is connected in parallel on the two ends of very first time relay power timing closing contact.

4. as claim 1 or 2 or 3 described motor self-decoupling decompressioning starting box; it is characterized in that: described motor self-decoupling decompressioning starting box also comprises protective circuit; described protective circuit comprises U; V; W three-phase current detection unit; described U; V; the circuit of W three-phase current detection unit is identical; include current transformer; thermal relay; the normally opened contact of second relay; current transformer is arranged on the corresponding phase line; two outputs of current transformer; the direct ground connection of one end; ground connection after the other end is connected with thermal relay, the normally opened contact of second relay is connected in parallel on the two ends of thermal relay.

5. motor self-decoupling decompressioning starting box as claimed in claim 4 is characterized in that: be serially connected with Current Display on the U phase current mutual inductor circuit in the described motor self-coupling decompression starting protective circuit.

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