CN210667397U

CN210667397U - Three-phase motor start-stop control fault demonstration circuit

Info

Publication number: CN210667397U
Application number: CN201920804762.5U
Authority: CN
Inventors: 胡帆
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-05-30
Filing date: 2019-05-30
Publication date: 2020-06-02
Anticipated expiration: 2029-05-30

Abstract

The utility model relates to a three-phase motor opens and stops control fault demonstration circuit, including isolator, first contactor main contact and coil, coupling circuit, stop button, the auxiliary contact of start button and first contactor, three phase current's power end is respectively through isolator, first contactor main contact connects to three phase motor's power end, three phase current's wherein double-phase power end connects to coupling circuit's input through isolator, coupling circuit's output one end is through start button, stop button and first contactor coil connect to coupling circuit's the output other end, the auxiliary contact who has first contactor at start button's both ends parallel connection, still include the third switch, the third switch is established ties on coupling circuit's output circuit. On original open and stop control circuit basis, between start button and stop button, increase three switch and the supplementary normally closed contact of a contactor, can demonstrate three kinds of common faults that three-phase motor opened and stop control circuit, have the simple and practical characteristics of circuit.

Description

Three-phase motor start-stop control fault demonstration circuit

Technical Field

The utility model belongs to the electron field especially relates to a three-phase motor opens and stops control circuit.

Background

As shown in fig. 1, the three-phase motor start-stop control circuit has the following working principle: after the isolating switch QS is switched on and power is supplied, the control loop is electrified. When the starting button QA is pressed down, the contactor coil KM is electrified, the first contactor auxiliary contact KM-2 is closed and self-protected, and the contactor main contact KM-1 is closed, the motor starts to operate. If the stop button TA is pressed during the operation, the motor stops operating. If the motor is overheated in operation, the thermal relay FR acts and the motor stops running.

During the assembling and debugging process, the following three common faults can occur:

the first type of failure is a failed start. Namely, after the QS switch is switched on, the QA is pressed, and the motor cannot be started. One of the causes of the failure is a broken control loop.

The second fault is that the power-on self-starting is carried out and the motor is out of control. After the isolating switch QS is switched on, the start button QA is not pressed, the motor starts to operate, the stop button TA is pressed, the motor cannot stop, and the contactor is always in a frequent action state that the contactor is powered on and is immediately disconnected and then powered on unless the stop button TA is pressed all the time, and finally the motor can be stopped only by switching off and powering off the isolating switch QS. The failure reason is that the self-protection contact is supposed to be a normally open contact, but is connected to form a normally closed contact.

The third fault is a start-up jog. That is, after the isolating switch QS is switched on, the motor can only be operated by pressing the start button QA all the time, and once the start button QA is released, the motor stops. The failure cause is the disconnection of the self-protection loop.

The three reasons for the occurrence of the fault relate to the line, the device and the connection relationship of the two. It is easy for beginners to confuse. If a three-phase motor start-stop control circuit fault demonstration device is provided, the three common fault phenomena are represented, and therefore beginners can master the basic principle of motor start-stop control and the common fault investigation.

Disclosure of Invention

An object of the utility model is to provide a three-phase motor opens and stops control fault demonstration circuit can demonstrate three-phase motor and open at least one common fault who stops control circuit, has the simple and practical characteristics of circuit.

The utility model adopts the following technical scheme:

the three-phase motor start-stop control fault demonstration circuit comprises an isolating switch, a first contactor main contact and a coil, a coupling circuit, a stop button, a start button and an auxiliary contact of a first contactor, wherein the power supply end of a three-phase power supply is connected to the power supply end of the three-phase motor through the isolating switch and the first contactor main contact respectively, the two-phase power supply end of the three-phase power supply is connected to the input end of the coupling circuit through the isolating switch, the output end of the coupling circuit is connected to the other end of the output end of the coupling circuit through the start button, the stop button and the first contactor coil, the auxiliary contact of the first contactor is connected to two ends of the start button in parallel, and the three-phase motor start-stop control fault demonstration circuit.

The three-phase motor start-stop control fault demonstration circuit further comprises a first switch, the first switch is connected with the auxiliary contact of the first contactor in series, and the first switch and the auxiliary contact of the first contactor which are connected in series are connected to two ends of the start button in parallel.

The three-phase motor start-stop control fault demonstration circuit further comprises a second switch and a third contactor normally closed contact, the second switch is connected with the third contactor normally closed contact in series, and the second switch and the third contactor normally closed contact which are connected in series are connected at two ends of the starting button in parallel.

The three-phase motor start-stop control fault demonstration circuit further comprises a thermal relay, and the thermal relay is connected in series with an output loop of the coupling circuit.

The coupling circuit includes a transformer.

It can be known from the above description of the present invention, compared with the prior art, the beneficial effects of the present invention are:

the utility model discloses owing to adopt above-mentioned scheme original open stop control circuit basis, start button and stop button between, increase the third switch with, can demonstrate three phase motor and open at least one kind common trouble of starting and stopping control circuit, have the simple and practical characteristics of circuit.

Drawings

FIG. 1 is a schematic diagram of a prior art circuit;

fig. 2 is a schematic circuit diagram according to an embodiment of the present invention.

Detailed Description

In order to make the principle and advantages of the present invention become clearer, the following description will proceed with further detailed description in conjunction with the accompanying drawings and specific embodiments. In the present embodiment, the specific embodiments described are only for explaining the present invention, and are not used to limit the present invention.

Example one

As shown in fig. 2, the three-phase motor start-stop control fault demonstration circuit comprises an isolating switch QS, a first contactor main contact point KM-1, a coil KM, a coupling circuit, a stop button TA, a start button QA and a first contactor auxiliary contact point KM-2. The coupling circuit includes a transformer T. An isolating switch QS is connected to the power supply end of a three-phase motor through a first contactor main contact KM-1, the input end of a transformer T is connected to the output end of the three-phase power supply, one end of the output end of the transformer T is connected to the other end of the output end of the transformer T through a start button QA, a stop button TA and a first contactor coil KM, an auxiliary contact KM-2 of the first contactor is connected in parallel with the two ends of the start button QA, the isolating switch further comprises a first switch K1, a second switch K2, a third switch K3 and a third contactor normally closed contact KM-3, the first switch K1 is connected in series with the auxiliary contact KM-2 of the first contactor, the first switch K1 and the auxiliary contact KM-2 of the first contactor are connected in parallel with the two ends of the start button QA, the second switch K2 and the third contactor normally closed contact KM-3 are connected in series, and the second switch K2 and the third contactor contact KM-3, the third switch K3 is connected in series with the output loop of the transformer T. The transformer T also comprises a thermal relay FR, and the thermal relay FR is connected in series on an output loop of the transformer T.

The basic principle is as follows:

as shown in FIG. 2, switches K1, K2, K3 and a contactor auxiliary normally closed contact KM-3 are added.

Wherein the first switch K1 controls the auxiliary contact (self-protection contact) KM-2 of the first contactor; the second switch K2 controls an auxiliary normally closed contact KM-3 of the third contactor; the third switch K3 controls the loop to be broken.

If the normal start-stop control of the motor is realized, the first switch K1 is closed, the second switch K2 is opened, and the third switch K3 is closed. Fig. 2 functions identically to fig. 1.

If the first fault is simulated, the first switch K1 is closed, the second switch K2 is opened, and the third switch K3 is opened. I.e. by the third switch K3 being open to demonstrate a control loop disconnection.

If a second fault is simulated, the first switch K1 is opened, the second switch K2 is closed, and the third switch K3 is closed. This places the activation button QA in parallel with the normally closed contacts.

If a third fault is simulated, the first switch K1 is opened, the second switch K2 is opened, and the third switch K3 is closed. I.e. the start button QA has no self-holding loop.

It is right to have used specific individual example above the utility model discloses expound, only be used for helping to understand the utility model discloses, not be used for the restriction the utility model discloses. To the technical field of the utility model technical personnel, the foundation the utility model discloses an idea can also be made a plurality of simple deductions, warp or replacement.

Claims

1. Three-phase motor opens and stops control fault demonstration circuit, including isolator, first contactor main contact and coil, coupling circuit, stop button, the auxiliary contact of start button and first contactor, three phase current's power end is respectively through isolator, first contactor main contact connects to three-phase motor's power end, three phase current's wherein two-phase power end connects to coupling circuit's input through isolator, coupling circuit's output one end is through start button, stop button and first contactor coil connect to coupling circuit's the output other end, the auxiliary contact that has first contactor at start button's both ends parallel connection, its characterized in that: and the third switch is connected in series on the output loop of the coupling circuit.

2. The three-phase motor start-stop control fault demonstration circuit of claim 1, characterized in that: the starting button further comprises a first switch, the first switch is connected with the auxiliary contact of the first contactor in series, and the first switch and the auxiliary contact of the first contactor which are connected in series are connected to two ends of the starting button in parallel.

3. The three-phase motor start-stop control fault demonstration circuit of claim 2, characterized in that: the starting button is characterized by further comprising a second switch and a third contactor normally-closed contact, wherein the second switch is connected with the third contactor normally-closed contact in series, and the second switch and the third contactor normally-closed contact which are connected in series are connected with the two ends of the starting button in parallel.

4. The three-phase motor start-stop control fault demonstration circuit of claim 3, characterized in that: the thermal relay is connected in series with an output loop of the coupling circuit.

5. The three-phase motor start-stop control fault demonstration circuit of claim 4, wherein: the coupling circuit includes a transformer.