CN210780095U

CN210780095U - Manual switching circuit for multiple working voltages of complete set of electrical equipment

Info

Publication number: CN210780095U
Application number: CN201921652214.1U
Authority: CN
Inventors: 王蔚; 曹泉泉
Original assignee: Hubei Senyuan Century Electric Group Co ltd
Current assignee: Hubei Senyuan Century Electric Group Co ltd
Priority date: 2019-09-30
Filing date: 2019-09-30
Publication date: 2020-06-16
Anticipated expiration: 2029-09-30

Abstract

The utility model relates to a manual switching circuit of multiple operating voltage of complete set electrical equipment, judge return circuit and warning circuit including manual switching return circuit, voltage, the input and the three phase current of manual switching return circuit are connected, and the earthing terminal of manual switching return circuit is connected with three phase current's zero line electricity, and manual switching return circuit is connected with voltage judgement return circuit electricity, and manual switching return circuit is connected with the warning circuit electricity, and voltage judgement return circuit and warning circuit are connected with the external power source electricity respectively. The utility model discloses a switching circuit, the different voltages of access just can be realized to the simple operation in manual switching return circuit of operating personnel accessible to make the voltage judge the different voltages that the return circuit can judge the switch-on, and report to the police when the gear in manual switching return circuit is inconsistent with actual access voltage, make things convenient for relevant personnel in time to know, realize the access voltage self-adaptation to the difference, thereby reduce operating voltage switching work load, improve work efficiency, also reduce the error rate simultaneously, improve equipment's power supply stability.

Description

Manual switching circuit for multiple working voltages of complete set of electrical equipment

Technical Field

The utility model relates to an electrical equipment technical field especially relates to a manual switching circuit of multiple operating voltage of complete set electrical equipment.

Background

At present, in some special application occasions, the same electrical equipment is often required to be connected with multiple paths of different voltage grades, and when the similar application occasions are met, in order to be suitable for multiple working voltages, secondary wiring is often changed during voltage switching, a protection fixed value is reset, and even components and parts are replaced. The resulting change is labor intensive and prone to errors in the change. Particularly, in some electrical equipment in large laboratories, because the test needs to frequently switch the working voltage, if voltage switching needs to be changed greatly each time, accidents are easy to happen, and the working efficiency is very affected.

Disclosure of Invention

The utility model aims to solve the technical problem that to the not enough of above-mentioned prior art, provide a multiple operating voltage manual switching circuit of complete set electrical equipment.

The utility model provides a manual switching circuit of multiple operating voltage of complete set electrical equipment, judge return circuit and warning return circuit including manual switching return circuit, voltage, the input and the three phase current of manual switching return circuit are connected, the earthing terminal and the zero line electricity of three phase current of manual switching return circuit are connected, manual switching return circuit with voltage is judged the return circuit electricity and is connected, manual switching return circuit with the warning return circuit electricity is connected, voltage is judged return circuit and warning return circuit and is connected with the external power source electricity respectively.

The utility model has the advantages that: the utility model discloses a manual switching circuit of multiple operating voltage of complete set electrical equipment, when the access voltage that inserts complete set electrical equipment needs to change, operating personnel can just can realize the different voltages that insert through the simple operation in manual switching return circuit, thereby make the different voltages that the switch-on can be judged in the voltage judgement return circuit to report to the police when the gear in manual switching return circuit is inconsistent with actual access voltage, make things convenient for relevant personnel to in time know, realize the access voltage self-adaptation to the difference, thereby reduce operating voltage switching work load, improve work efficiency, also reduce the error rate simultaneously, improve equipment's power supply stability.

On the basis of the technical scheme, the utility model discloses can also do as follows the improvement:

further: the manual switching circuit comprises a change-over switch SA, a high-voltage transformer TVa, a high-voltage transformer TVb, a high-voltage transformer TVc, a low-voltage transformer LTVa, a low-voltage transformer LTvb, a low-voltage transformer LTVc, an overvoltage relay KV1, an overvoltage relay KV2, an intermediate relay KA1, an intermediate relay KA2, a fuse FU1, a fuse FU2, a fuse FU3, a fuse FU4, a fuse FU5, a fuse FU6, a fuse 7, a fuse FU8, a fuse FU9, a fuse FU10, a fuse FU11 and a fuse FU12, wherein the pins 2, 4 and 6 of the change-over switch SA are respectively and correspondingly and electrically connected with the phases A, B and C of a three-phase power supply, the pins 1, 3 and 5 of the change-over switch SA are respectively and electrically connected with one end of a normally open contact of the overvoltage KV1, and the high-voltage transformer TVa, the high-voltage transformer TVb and, the other end of the normally open contact of the overvoltage relay KV1 is electrically connected with one end of the first transformation ratio winding of the high-voltage transformer TVa, the high-voltage transformer TVb and the high-voltage transformer TVc through the fuse FU1, the fuse FU2 and the fuse FU3 respectively, the other end of the first transformation ratio winding of the high-voltage transformer TVa, the high-voltage transformer TVb and the high-voltage transformer TVc is grounded respectively, the 10 pin, the 12 pin and the 14 pin of the change-over switch SA are electrically connected with the A phase, the B phase and the C phase of a three-phase power supply correspondingly respectively, the 9 pin, the 11 pin and the 13 pin of the change-over switch SA are electrically connected with one end of the normally open contact of the overvoltage relay KA1 respectively, the other end of the normally open contact of the overvoltage relay KA1 is electrically connected with one end of the second transformation ratio winding of the high-voltage transformer TVa, the high-voltage transformer TVb and the high-voltage transformer TVc, the other ends of the second transformation ratio windings of the high-voltage transformer TVa, the high-voltage transformer TVb and the high-voltage transformer TVc are respectively grounded, the coil of the overvoltage relay KV1 and the coil of the overvoltage relay KV2 are electrically connected between any two phases of a three-phase power supply, one end of a normally open contact of the intermediate relay KA2 is respectively and correspondingly electrically connected with one ends of the second transformation ratio windings of the high-voltage transformer Tva, the high-voltage transformer TVb and the high-voltage transformer TVc through the fuse FU7, the fuse FU8 and the fuse FU9, the other end of the normally open contact of the intermediate relay KA2 is respectively and electrically connected with one ends of primary windings of the low-voltage transformer LTVa, the low-voltage transformer LTvb and the low-voltage transformer LTVc, the other ends of the primary windings of the low-voltage transformer LTVa, the low-voltage transformer LTVb and the low-voltage transformer LT, One ends of secondary windings of a low-voltage transformer LTVb and a low-voltage transformer LTVc are respectively and electrically connected with a zero line of a three-phase power supply, the other ends of stimulating windings of the low-voltage transformer LTVa, the low-voltage transformer LTVb and the low-voltage transformer LTVc are respectively and correspondingly and electrically connected with

pins

17, 19 and 21 of the change-over switch SA through a fuse FU10, a fuse FU11 and a fuse FU12, and

pins

18, 20 and 22 of the change-over switch SA are respectively and correspondingly and electrically connected with an A phase, a B phase and a C phase of the three-phase power supply.

The beneficial effects of the further scheme are as follows: the access gear can be adjusted through the manual switching circuit, so that the overvoltage relay KV1 and the overvoltage relay KV2 act or do not act, the self-adaption of different access voltages is realized, and meanwhile, the voltage judgment circuit can judge the different accessed voltages conveniently.

Further: the voltage judging loop comprises a time relay KT1, a time relay KT2 and a breaker QF1, a normally closed contact of an overvoltage relay KV1, a normally open contact of the overvoltage relay KV2 and a coil of the time relay KT1 are sequentially connected in series to form a first branch, a normally closed contact of an overvoltage relay KV2 is connected in series with the coil of the time relay KT2 in series to form a second branch, an electrifying delay closed contact of the time relay KT1 and a coil of an intermediate relay KA1 are connected in series to form a third branch, an electrifying delay closed contact of the time relay KT2 and a coil of the intermediate relay KA2 are connected in series to form a fourth branch, and the first branch, the second branch, the third branch and the fourth branch are connected in parallel and then connected with the breaker QF1 in series between the positive and negative poles of an external power supply.

The beneficial effects of the further scheme are as follows: the voltage judgment circuit can switch in the manual switching circuit to cause the corresponding overvoltage relay to act or keep not to act when voltage is not stopped, and different branches are conducted, so that the alarm circuit can display different indication information according to the working states of different relays.

Further: the alarm loop comprises an intermediate relay KA3, a breaker QF3 and an alarm indicator lamp HY, wherein a pin 7, a pin 15, a pin 23 and a pin 25 of the change-over switch SA are respectively and correspondingly electrically connected with a normally open contact of the overvoltage relay KV1, a normally open contact of the intermediate relay KA1, an intermediate relay KA2 and one end of an intermediate relay KA3, the normally open contact of the overvoltage relay KV1, the normally open contact of the intermediate relay KA1, the other ends of the intermediate relay KA2 and the intermediate relay KA3 are respectively and electrically connected with one end of the breaker QF3, the other end of the breaker QF3 is electrically connected with one output end of an external power supply, a pin 8, a pin 16 and a pin 24 of the change-over switch SA are respectively and electrically connected with one end of a coil of the intermediate relay KA3, the pin 26 of the change-over switch SA is electrically connected with the other end of the coil of the intermediate relay KA3, the other end of the coil of the intermediate relay KA3 is electrically connected with the other output end of the external power supply.

The beneficial effects of the further scheme are as follows: through the warning return circuit can be when change over switch SA gear is inconsistent with actual access voltage for relay KA3 loses the electricity, and pilot lamp HY switches on and lights, and reports to the police, conveniently in time notifies relevant personnel that access voltage appears unusually.

Drawings

Fig. 1 is a schematic diagram of the structure of the automatic switching loop of the present invention;

fig. 2 is a schematic diagram of the structure of the voltage judging circuit of the present invention;

fig. 3 is a schematic diagram of the alarm circuit structure of the present invention.

Detailed Description

The principles and features of the present invention are described below in conjunction with the following drawings, the examples given are only intended to illustrate the present invention and are not intended to limit the scope of the present invention.

The utility model provides a multiple operating voltage manual switching circuit of complete set of electrical equipment which characterized in that: the voltage detection circuit comprises a manual switching loop, a voltage judgment loop and an alarm loop, wherein the input end of the manual switching loop is electrically connected with a three-phase power supply, the grounding end of the manual switching loop is electrically connected with a zero line of the three-phase power supply, the manual switching loop is electrically connected with the voltage judgment loop, the manual switching loop is electrically connected with the alarm loop, and the voltage judgment loop and the alarm loop are respectively electrically connected with an external power supply. The utility model discloses a manual switching circuit of multiple operating voltage of complete set electrical equipment, when the access voltage that inserts complete set electrical equipment needs to change, operating personnel can just can realize the different voltages that insert through the simple operation in manual switching return circuit, thereby make the different voltages that the switch-on can be judged in the voltage judgement return circuit to report to the police when the gear in manual switching return circuit is inconsistent with actual access voltage, make things convenient for relevant personnel to in time know, realize the access voltage self-adaptation to the difference, thereby reduce operating voltage switching work load, improve work efficiency, also reduce the error rate simultaneously, improve equipment's power supply stability.

As shown in fig. 1, in the embodiment(s) provided in the present invention, the manual switching circuit comprises a switch SA, a high-voltage transformer TVa, a high-voltage transformer TVb, a high-voltage transformer TVc, a low-voltage transformer LTVa, a low-voltage transformer LTVb, a low-voltage transformer LTVc, an overvoltage relay KV1, an overvoltage relay KV2, an intermediate relay KA1, an intermediate relay KA2, a fuse FU1, a fuse FU2, a fuse FU3, a fuse FU4, a fuse FU5, a fuse FU6, a fuse FU7, a fuse FU8, a fuse FU9, a fuse FU10, a fuse FU11 and a fuse FU12, wherein the pins 2, 4 and 6 of the switch SA are respectively electrically connected with the corresponding phases a, B and C of the three-phase power supply, the pins 1, 3 and 5 of the switch SA are respectively electrically connected with one end of the normally open contact of the overvoltage relay KV1, and the high-voltage transformer TVa, The other ends of normally open contacts of the overvoltage relay KV1 are electrically connected with one ends of the first transformation ratio windings of the high-voltage transformer TVa, the high-voltage transformer TVb and the high-voltage transformer TVc through the fuse FU1, the fuse FU2 and the fuse FU3 respectively, the other ends of the first transformation ratio windings of the high-voltage transformer TVa, the high-voltage transformer TVb and the high-voltage transformer TVc are grounded respectively, a pin 10, a pin 12 and a pin 14 of the change-over switch SA are electrically connected with the phase A, the phase B and the phase C of a three-phase power supply correspondingly, a pin 9, a pin 11 and a pin 13 of the change-over switch SA are electrically connected with one end of a normally open contact of the relay KA1 respectively, and the other end of the normally open contact of the overvoltage relay KA1 is electrically connected with the high-voltage transformer TVa, the fuse FU4, the fuse FU5 and the fuse FU6 respectively, One ends of second transformation ratio windings of the high-voltage transformer TVb and the high-voltage transformer TVc are electrically connected, the other ends of the second transformation ratio windings of the high-voltage transformer TVa, the high-voltage transformer TVb and the high-voltage transformer TVc are respectively grounded, a coil of the overvoltage relay KV1 and a coil of the overvoltage relay KV2 are electrically connected between any two phases of a three-phase power supply, one end of a normally open contact of the intermediate relay KA2 is electrically connected with one ends of the second transformation ratio windings of the high-voltage transformer Tva, the high-voltage transformer TVb and the high-voltage transformer TVc in a one-to-one correspondence manner through the fuse FU7, the fuse FU8 and the fuse FU9, the other end of the normally open contact of the intermediate relay KA2 is electrically connected with one ends of primary windings of the low-voltage transformer LTVa, the low-voltage transformer LTVb and the low-voltage transformer LTVc, the other ends of the primary windings of the low-voltage, one ends of secondary windings of the low-voltage transformer LTVa, the low-voltage transformer LTvb and the low-voltage transformer LTVc are respectively and electrically connected with a zero line of a three-phase power supply, the other ends of stimulating windings of the low-voltage transformer LTVa, the low-voltage transformer LTVb and the low-voltage transformer LTVc are respectively and correspondingly electrically connected with

pins

17, 19 and 21 of the change-over switch SA through the fuse FU10, the fuse FU11 and the fuse FU12, and

pins

18, 20 and 22 of the change-over switch SA are respectively and correspondingly and electrically connected with a phase, a phase and a phase of the three-phase power supply.

The access gear can be adjusted through the manual switching circuit, so that the overvoltage relay KV1 and the overvoltage relay KV2 act or do not act, the self-adaption of different access voltages is realized, and meanwhile, the voltage judgment circuit can judge the different accessed voltages conveniently.

The utility model discloses in, high-voltage transformer TVa, high-voltage transformer TVb and high-voltage transformer TVc are two transformation ratio voltage transformer, and it has two transformation ratio windings, for convenient the description, with these two transformation ratio windings first transformation ratio winding and second transformation ratio winding for short respectively, the utility model discloses in, we judge the condition as voltage with the produced induced voltage of first transformation ratio winding.

The utility model discloses in, change over switch SA is used for switching over the voltage mode, can switch over between the gear of difference, and different gears switch on between corresponding different pins, and all pins all do not switch on at "stop" gear. In addition, the indicator light HY is used for lightening an alarm when the voltage gear is not consistent with the actual access voltage.

As shown in fig. 2, in one or more embodiments provided by the present invention, the voltage judging circuit includes a time relay KT1, a time relay KT2 and a circuit breaker QF1, the normally closed contact of the overvoltage relay KV1, the normally open contact of the overvoltage relay KV2 and the coil of the time relay KT1 are sequentially connected in series to form a first branch, the normally closed contact of the overvoltage relay KV2 is connected in series with the coil of the time relay KT2 to form a second branch, the electrified delay closing contact of the time relay KT1 is connected with the coil of the intermediate relay KA1 in series to form a third branch, the electrified delay closing contact of the time relay KT2 is connected with the coil of the intermediate relay KA2 in series to form a fourth branch, one contact point of the circuit breaker QF1, the first branch, the second branch, the third branch, the fourth branch and the other normally open contact of the circuit breaker QF1 are connected in series between the positive pole and the negative pole of an external power supply. Through the voltage judging circuit, different branches can be conducted after the corresponding overvoltage relay acts or keeps inactive due to the automatic switching circuit according to different access voltages, so that the alarm circuit can display different indication information according to the working states of different relays. Here, the delay ranges of the time relay KT1 and the time relay KT2 can be flexibly set according to actual needs.

As shown in fig. 3, in one or more embodiments of the present invention, the alarm circuit includes an intermediate relay KA3, a circuit breaker QF3 and an alarm indicator HY, wherein the 7, 15, 23 and 25 pins of the switch SA are electrically connected with the normally open contact of the overvoltage relay KV1, the normally open contact of the intermediate relay KA1, the normally open contact of the intermediate relay KA2 and one end of the intermediate relay KA3 respectively, the normally open contact of the overvoltage relay KV1, the normally open contact of the intermediate relay KA1, the other ends of the intermediate relay KA2 and the intermediate relay KA3 are electrically connected with one end of the circuit breaker QF3 respectively, the other end of the circuit breaker QF3 is electrically connected with an output end of an external power source, the 8, 16 and 24 pins of the switch SA are electrically connected with one end of the coil of the intermediate relay KA3 respectively, the 26 pin of the switch SA is electrically connected with the other end of the coil 3 through the alarm indicator HY, the other end of the coil of the intermediate relay KA3 is electrically connected with the other output end of the external power supply.

Through the warning return circuit can be when change over switch SA gear is inconsistent with actual access voltage for relay KA3 loses the electricity, and pilot lamp HY switches on and lights, and reports to the police, conveniently in time notifies relevant personnel that access voltage appears unusually. We will use the same equipment to connect three kinds of voltages as an example below, explain and explain the working principle of the manual switching circuit of multiple working voltages of the complete set of electrical equipment of the utility model, and the three kinds of voltages are 20kV,10kV and 3kV respectively.

In one or more embodiments of the present invention, the transformation ratios of the first transformation ratio winding and the second transformation ratio winding of the high voltage transformer TVa, the high voltage transformer TVb and the high voltage transformer TVc are respectively 20/√ 3/0.1/√ 3/0.2/√ 3 kV; the transformation ratio of the low-voltage transformer LTVa, the low-voltage transformer LTvb and the low-voltage transformer LTVc is 30/√ 3/100/√ 3V; the action threshold value of the overvoltage relay KV1 is 75V, and the action threshold value of the overvoltage relay KV2 is 22.5V.

In one or more embodiments of the present invention, the switch SA can be switched between "3 kV,10kV, 20kV, stop" 4 steps, wherein pins 1-2, 3-4, 5-6, 7-8, 25-26 are turned on at "20 kV" step; pins 9-10, 11-12, 13-14, 15-16 and 25-26 are conducted at a 10kV gear; the nodes 17-18, 19-20, 21-22, 23-24 and 25-26 are conducted in a 3kV gear.

When the voltage connected to the equipment is 20kV, the voltage of an induction line of a first transformation ratio winding (namely 20/√ 3/0.1/√ 3 winding) of the high-voltage transformer is 100V and is higher than the action threshold of the overvoltage relay KV1 and the action threshold of the overvoltage relay KV2, the overvoltage relay KV1 and the overvoltage relay KV2 both act, and the normally-open contact of the overvoltage relay KV1 is closed. At this time, if the voltage mode change-over switch is placed in a 20kV gear position, pins 1-2, 3-4, 5-6, 7-8 and 25-26 of the change-over switch SA are correspondingly switched on, and the small voltage buses YMa, YMb and YMc are connected with voltage signals. Meanwhile, the intermediate relay KA3 is powered on, the normally open contact of the intermediate relay KA3 is disconnected, and the indicator light HY loses power and does not give an alarm.

When the voltage connected to the equipment is 10kV, the voltage of an induction line of a first transformation ratio winding (namely 20/√ 3/0.1/√ 3 winding) of the high-voltage transformer is 50V, is lower than the action threshold of the overvoltage relay KV1 and higher than the action threshold of the overvoltage relay KV2, the overvoltage relay KV1 does not act, and the overvoltage relay KV2 acts. The normally open contact of the overvoltage relay KV2 is closed, so that the time relay KT1 is electrified, and after a period of time (the time can be set by oneself), the electrified delay closed contact of the time relay KT1 is closed along with the normally open contact, so that the intermediate relay KA1 is electrified, and the normally open contact of KA1 is closed. At this time, if the voltage mode change-over switch is placed in a 10kV gear position, pins 9-10, 11-12, 13-14, 15-16 and 25-26 of the change-over switch SA are correspondingly switched on, and the voltage small buses YMa, YMb and YMc are switched in voltage signals. Meanwhile, the intermediate relay KA3 is powered on, the normally open contact of the intermediate relay KA3 is disconnected, and the indicator light HY loses power and does not give an alarm.

When the voltage connected to the equipment is 3kV, the voltage of an induction line of a first transformation ratio winding (namely 20/√ 3/0.1/√ 3 winding) of the high-voltage transformer is 15V, which is lower than the action threshold of the overvoltage relay KV1 and the action threshold of the overvoltage relay KV2, and neither the overvoltage relay KV1 nor the overvoltage relay KV2 acts. The time relay KT2 is electrified, and after a period of time (the time can be set by self), the electrified delay closed contact of the KT2 is closed, so that the intermediate relay KA2 is electrified, and the normally open contact of the KA2 is closed. The voltage of the induction line of the second transformation ratio winding (namely 20/√ 3/0.2/√ 3kV winding) of the high-voltage transformer is 30V, and after the normally open contact of the intermediate relay KA2 is closed, the induction line is boosted to 100V through the low-voltage transformer LTVa, the low-voltage transformer LTVb and the low-voltage transformer LTVc. At this time, if the voltage mode change-over switch is placed in a 3kV gear position, pins 17-18, 19-20, 21-22, 23-24 and 25-26 of the change-over switch SA are correspondingly switched on, and the voltage small buses YMa, YMb and YMc are switched in voltage signals. Meanwhile, the intermediate relay KA3 is powered on, the normally open contact of the intermediate relay KA3 is disconnected, and the indicator light HY loses power and does not give an alarm.

When the working voltage of the equipment is converted, if the gear of the conversion switch SA is inconsistent with the actual access voltage, the intermediate relay KA3 loses power, the indicator lamp HY gets power, the indicator lamp is on, and an alarm is given; if the gear of the change-over switch SA is set to stop, the change-over switch SA nodes 25-26 are disconnected, the indicator light HY loses power, and the indicator light is turned off.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. The utility model provides a multiple operating voltage manual switching circuit of complete set of electrical equipment which characterized in that: the voltage detection circuit comprises a manual switching loop, a voltage judgment loop and an alarm loop, wherein the input end of the manual switching loop is electrically connected with a three-phase power supply, the grounding end of the manual switching loop is electrically connected with a zero line of the three-phase power supply, the manual switching loop is electrically connected with the voltage judgment loop, the manual switching loop is electrically connected with the alarm loop, and the voltage judgment loop and the alarm loop are respectively electrically connected with an external power supply.

2. The manual switching circuit for multiple working voltages of complete set of electric equipment according to claim 1, characterized in that: the manual switching loop comprises a change-over switch SA, a high-voltage transformer TVa, a high-voltage transformer TVb, a high-voltage transformer TVc, a low-voltage transformer LTVa, a low-voltage transformer LTvb, a low-voltage transformer LTVc, an overvoltage relay KV1, an overvoltage relay KV2, an intermediate relay KA1, an intermediate relay KA2, a fuse FU1, a fuse FU2, a fuse FU3, a fuse FU4, a fuse FU5, a fuse FU6, a fuse FU7, a fuse FU8, a fuse FU9, a fuse 96FU 37, a fuse FU11 and a fuse FU12, wherein 2 pins, 4 pins and 6 pins of the change-over switch SA are respectively and correspondingly and electrically connected with an A phase, a B phase and a C of a three-phase power supply, the high-voltage transformer TVa, the high-voltage transformer TVb and the high-voltage transformer TVc respectively comprise a first transformation ratio winding and a second transformation winding, 1 pin, 3 pin and a 5 pin, the other end of the normally open contact of the overvoltage relay KV1 is electrically connected with one end of the first transformation ratio winding of the high-voltage transformer TVa, the high-voltage transformer TVb and the high-voltage transformer TVc through the fuse FU1, the fuse FU2 and the fuse FU3 respectively, the other end of the first transformation ratio winding of the high-voltage transformer TVa, the high-voltage transformer TVb and the high-voltage transformer TVc is grounded respectively, the 10 pin, the 12 pin and the 14 pin of the change-over switch SA are electrically connected with the A phase, the B phase and the C phase of a three-phase power supply correspondingly respectively, the 9 pin, the 11 pin and the 13 pin of the change-over switch SA are electrically connected with one end of the normally open contact of the overvoltage relay KA1 respectively, the other end of the normally open contact of the overvoltage relay KA1 is electrically connected with one end of the second transformation ratio winding of the high-voltage transformer TVa, the high-voltage transformer TVb and the high-voltage transformer TVc, the other ends of the second transformation ratio windings of the high-voltage transformer TVa, the high-voltage transformer TVb and the high-voltage transformer TVc are respectively grounded, the coil of the overvoltage relay KV1 and the coil of the overvoltage relay KV2 are electrically connected between any two phases of a three-phase power supply, one end of a normally open contact of the intermediate relay KA2 is respectively and correspondingly electrically connected with one ends of the second transformation ratio windings of the high-voltage transformer Tva, the high-voltage transformer TVb and the high-voltage transformer TVc through the fuse FU7, the fuse FU8 and the fuse FU9, the other end of the normally open contact of the intermediate relay KA2 is respectively and electrically connected with one ends of primary windings of the low-voltage transformer LTVa, the low-voltage transformer LTvb and the low-voltage transformer LTVc, the other ends of the primary windings of the low-voltage transformer LTVa, the low-voltage transformer LTVb and the low-voltage transformer LT, One ends of secondary windings of a low-voltage transformer LTVb and a low-voltage transformer LTVc are respectively and electrically connected with a zero line of a three-phase power supply, the other ends of stimulating windings of the low-voltage transformer LTVa, the low-voltage transformer LTVb and the low-voltage transformer LTVc are respectively and correspondingly and electrically connected with pins 17, 19 and 21 of the change-over switch SA through a fuse FU10, a fuse FU11 and a fuse FU12, and pins 18, 20 and 22 of the change-over switch SA are respectively and correspondingly and electrically connected with an A phase, a B phase and a C phase of the three-phase power supply.

3. The manual switching circuit for multiple working voltages of complete electrical equipment according to claim 2, characterized in that: the voltage judging loop comprises a time relay KT1, a time relay KT2 and a breaker QF1, wherein a normally closed contact of the overvoltage relay KV1, a normally open contact of the overvoltage relay KV2 and a coil of the time relay KT1 are sequentially connected in series to form a first branch, a normally closed contact of the overvoltage relay KV2 is connected in series with the coil of the time relay KT2 in series to form a second branch, an electrifying delay closed contact of the time relay KT1 and a coil of an intermediate relay KA1 are connected in series to form a third branch, an electrifying delay closed contact of the time relay KT2 and a coil of the intermediate relay KA2 are connected in series to form a fourth branch, and one normally open contact, the first branch, the second branch, the third branch and the fourth branch of the breaker QF1 and the other normally open contact of the breaker QF1 are connected in series between the positive pole and the negative pole of an.

4. The manual switching circuit for multiple working voltages of complete electrical equipment according to claim 2, characterized in that: the alarm loop comprises an intermediate relay KA3, a circuit breaker QF3 and an alarm indicator lamp HY, wherein the 7 pin, the 15 pin, the 23 pin and the 25 pin of the change-over switch SA are respectively and correspondingly electrically connected with the normally open contact of the overvoltage relay KV1, the normally open contact of the intermediate relay KA1, the normally open contact of the intermediate relay KA2 and one end of the normally closed contact of the intermediate relay KA3, the normally open contact of the overvoltage relay KV1, the normally open contact of the intermediate relay KA1, the normally open contact of the intermediate relay KA2 and the other end of the normally closed contact of the intermediate relay KA3 are respectively and electrically connected with one end of the normally open contact of the circuit breaker QF3, the other end of the normally open contact of the circuit breaker QF3 is electrically connected with one output end of an external power supply, the 8 pin, the 16 pin and the 24 pin of the change-over switch SA are respectively and electrically connected with one end of the coil of the intermediate relay KA3, and the 26 pin of the change-over switch SA is electrically And the other end of the coil of the intermediate relay KA3 is electrically connected with one end of the other normally open contact of the circuit breaker QF3, and the other end of the other normally open contact of the circuit breaker QF3 is electrically connected with the other output end of the external power supply.