JPH094947A - Refrigerating device - Google Patents

Abstract

PURPOSE: To make it possible to continue the operation of a refrigerator, even if chattering occurs at an electromagnetic contactor by switching a bypass contact to a bypass circuit when the counted value of a switching signal in a predetermined time from a contactor switching detector exceeds a preset predetermined value. CONSTITUTION: The switching state of an electromagnetic contactor 4 is detected by a contactor switching detector 30. A controller 5 judges the chattering of the contactor 4 based on the counted value of a switching signal in a predetermined time from the detector 30 by the detection. When the chattering is judged, i.e., when the counted value of the switching signal exceeds a preset predetermined value, the controller 5 switches a bypass contact 35 to the bypass circuit 40 for detouring an electric contact easily causing the chattering. Thus, even if the chattering occurs at the contactor 4, the operation of a refrigerator can be continued.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus which can prevent a fatal failure of a compressor in advance and can be temporarily operated continuously within a range without any trouble.

[0002]

2. Description of the Related Art FIG. 3 is a circuit diagram showing a control circuit for a general-purpose refrigeration system. In the figure, 1 is a three-phase AC power bus, 2 is a compressor motor that serves as a load, 3 is a circuit breaker for wiring, 4 is an electromagnetic contactor, and 6 is between the power bus 1 and the compressor motor 2. The main circuit 5 having the electromagnetic contactor 4 formed to feed and cut off the electric motor 2 for the compressor is formed in an annular shape based on the control buses 5a and 5b branching from the main circuit 6 to form the electromagnetic contactor 4. It is a control circuit having a driving electromagnetic coil 4b. Reference numerals 10a and 19b are bimetal type temperature switches (for example, a discharge pipe temperature switch provided on the discharge side of the compressor),
Alternatively, it represents a mechanical contact that is opened and closed by a mechanical detection means such as a spring type or bellows type pressure switch (for example, a high-pressure pressure switch provided on the compressor discharge side). Reference numerals 20a and 20b represent electric contacts which are electrically driven and are represented by a relay contact and the like.
a or 21b via one or more sensors (eg,
Pressure sensors, temperature sensors, etc.) 22a, 22b. Further, 4b is an operation coil for operating the electromagnetic contactor 4.

Next, the operation will be described. From the electromagnetic bus 1 through the wiring breaker 3, the power source is controlled by the control buses 5a and 5b.
Is supplied to the control circuit 5. At this time, mechanical contact 1
0a, 10b and the electrical contacts 20a, 20b are all closed, the operating coil 4b is energized, thereby closing the electromagnetic contactor 4, energizing the compressor motor 2,
The compressor starts. On the other hand, the mechanical contacts 10a, 10b,
Alternatively, if at least one of the electrical contacts 20a, 20b is open, the operating coil 4b is not energized, the electromagnetic contactor 4 is opened, the compressor motor 2 is de-energized, and the compressor Stops. In addition, the controllers 21a, 2
1b compares the signals from the sensors 22a and 22b with preset values based on a prestored program, and opens and closes the electrical contacts 20a and 20b. The general-purpose control circuit that controls the refrigeration system is configured as described above, and the power supply busbar 1
If the electrical contacts 20a, 20b malfunction and chattering (high-frequency opening / closing) occurs due to noise from the sensors or the sensors 22a, 22b, or a bug in the controller 21a, 21b on the program, the motor 2 for the compressor is There was a problem in that the lubricating oil was not sufficiently supplied to the bearing (not shown) of the compressor due to repeated operation and stoppage in a short time, resulting in failure.

[0004]

Therefore, in order to solve this kind of problem, in JP-A-5-276692, an operating coil of an electromagnetic contactor is detected when chattering of a contact or an electromagnetic contactor is detected. There is disclosed a control circuit for blocking the energization of the compressor and stopping the operation of the compressor. The control circuit disclosed above is shown in FIG. In the figure,
Reference numeral 4a is an interlocking contact that interlocks with the opening and closing of the electromagnetic contactor 4, 30 is a current detector for detecting the opening and closing of the interlocking contact 4a by a current, and 31 is a control device. This control device 31
An input device 32 that receives a signal from the current detector 30, a comparison calculation unit 33 that determines chattering, and a comparison calculation unit 3
3 and an output unit 34 for opening and closing the contact 35a based on the comparison calculation result. In the control circuit of FIG. 4, when the electromagnetic contactor 4 causes chattering, the interlocking contact 4a also causes chattering. The current flowing through the interlocking contact 4a is turned on / off by this chattering.
However, this is detected by the current detector 30, the number of times of ON is counted by the input unit 32, and the result is transmitted to the comparison calculation unit 33. When the number of ON times generated within a predetermined time exceeds a predetermined value set in advance, the comparison calculation unit 33 determines that this is chattering, opens the contact 35a, and stops the operation of the compressor. It is like this. However, with the control circuit as described above, when the chattering occurs, the refrigeration system is stopped immediately to protect the compressor, so the temperature of the frozen product rises while the system is stopped. Then, there was a problem of causing quality deterioration.

The present invention has been made to solve the above problems, and even if chattering occurs in the electromagnetic contactor, the operation of the refrigerating apparatus is continued as much as possible to damage the object to be frozen. It is an object of the present invention to provide a refrigeration system capable of minimizing the above.

[0006]

In order to achieve the above-mentioned object, a refrigerating apparatus according to the present invention is formed between a power bus and a compressor electric motor to supply electric power to the compressor electric motor and turn off the electric power. A main circuit having an electromagnetic contactor, a control circuit having an electromagnetic coil formed by branching from the main circuit to drive the electromagnetic contactor, and two or more contacts connected in series with the electromagnetic coil in the control circuit and including electrical contacts And a bypass circuit that is connected in parallel to the control circuit by bypassing the electric contact, a bypass contact that is interposed between the electric contact and the electromagnetic coil and that switches the circuit connection between the bypass circuit and the control circuit, and the electromagnetic contact. The contactor open / close detector that detects the opening / closing of the switch and the switch that switches the bypass contact to the bypass circuit when the count value of the open / close signal from the contactor open / close detector exceeds the preset predetermined value. It is obtained by employing the structure formed by and a device.

Further, the bypass circuit in the structure of claim 1 is provided with an alternative contact having a function of replacing the electric contact.

Further, in the structure of claim 1 or claim 2, when the bypass contact is switched to the bypass circuit, an abnormal output portion is provided for outputting a display or alarm indicating switching. Is.

[0009]

In the refrigerating apparatus according to the present invention, first, the contactor open / close detector detects the open / closed state of the electromagnetic contactor. Then, the control device determines chattering of the electromagnetic contactor based on the count value of the opening / closing signal from the contactor opening / closing detector within a predetermined time. When it is determined that the contact is chattering, the control device switches the bypass contact to the bypass circuit that bypasses the electrical contact that relatively easily causes chattering. As a result, chattering of the electromagnetic contactor subsides, and the compressor continues operating as it is.

Further, as described above, when chattering occurs, the bypass contact is switched to the bypass circuit to interrupt the electric contact, but the function of the interrupted electric contact is replaced by the alternative contact of the bypass circuit. Be driven.

Further, when chattering occurs, when the control device switches the bypass contact to the bypass circuit, at the same time, the abnormality output section outputs a display or alarm indicating the switching. Therefore, the occurrence of chattering is notified to the outside.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. The same components as those of the general-purpose device or the conventional device shown in FIGS. 3 and 4 are designated by the same reference numerals and the description thereof will be omitted. Embodiment 1 FIG. 1 is an open circuit diagram showing a control circuit for a refrigeration system according to a first embodiment of the present invention. In the figure, 6 is a main circuit having an electromagnetic contactor 4 which is formed between a power source bus 1 and a compressor electric motor 2 and which feeds and cuts power to the compressor electric motor 2 and 5 is a control branched from the main circuit 6. The control circuit has an electromagnetic coil 4b that is formed in an annular shape based on the bus bars 5a and 5b and that drives the electromagnetic contactor 4. Further, 10a and 10b are mechanical contacts, and 20a and 20b are electrical contacts that are opened / closed by command signals from the controllers 21a and 21b of the upper operation system. There can be any number. And 40 is the control circuit 5
A bypass circuit bypassing the electrical contacts 20a and 20b and connected in parallel, 35 is the electrical contact 20b and the electromagnetic coil 4
a bypass contact interposed between the bypass circuit 40 and the control circuit 5 for switching the circuit connection between the bypass circuit 40 side and the control circuit 5 side, 4a is an interlocking contact that opens and closes in conjunction with the electromagnetic contactor 4, and 30 is an interlocking contact 4
It is a current detector that detects opening / closing of a. In this case, the configuration including the interlocking contact 4a and the current detector 30 is an example of the contactor open / close detector. Reference numeral 31 is a control device for switching the bypass contact 35 to the bypass circuit 40 side when the count value of the open / close signal from the current detector 30 exceeds a preset predetermined value. The mechanical contacts 10 a and 10 b, the electrical contacts 20 a and 20 b, and the bypass contact 35 are connected to the operating coil 4 in the control circuit 5.
It is connected in series with b.

Controllers 21a and 21b of the upper operation system
May malfunction due to its power supply noise, noise from input / output lines, program bugs, and the like, and it is well known to cause the electrical contacts 20a and 20b to chatter. On the other hand, mechanical contacts 10a, 1 in a mechanical switch such as a bimetal type or a spring or bellows type.
In 0b, such a problem is small and chattering hardly occurs.

Therefore, in this embodiment, the bypass circuit 40 that bypasses the contacts 20a and 20b where chattering easily occurs is provided, and when the electromagnetic contactor 4 causes chattering, the connection state of the bypass contact 35 is changed to the bypass circuit 4.
Switching to the 0 side, the energization of the operating coil 4b is continued. As a result, chattering of the electrical contacts 20a, 20b is avoided. The chattering of the electromagnetic contactor 4 is detected by the controller 31 as in the conventional example. When the electromagnetic contactor 4 causes chattering, the interlocking contact 4a also causes chattering in conjunction with this. Due to this chattering, the current flowing through the interlocking contact 4a is turned ON / OF.
F, but this is detected by the current detector 30, and the input unit 32
The number of times of ON is counted and transmitted to the comparison calculation unit 33. When the number of ON times generated within a certain predetermined time exceeds a predetermined value set in advance, the comparison calculation unit 33 determines that this is chattering, and cuts off the circuits on the side of the electrical contacts 20a and 20b. , The bypass contact 35 is switched to connect to the bypass circuit 40 side.

As described above, according to this embodiment, when the control device 31 determines that chattering has occurred, the bypass contact 35 is switched to the bypass circuit 40 side to continue the energization of the operating coil 4b and the electric contact. The chattering of 20a and 20b can be avoided, and the operation of the refrigeration system can be continued. That is, even when chattering occurs, a fatal failure of the compressor can be prevented, and the refrigeration system can be urgently continued to operate in order to prevent damage to the frozen product.

Since chattering often occurs temporarily, it is necessary to return the bypass contact 35 to the control circuit 5 on the side of the electric contacts 20a, 20b after a lapse of a predetermined time.
By setting the program of the comparison calculation unit 33, the refrigeration apparatus can be operated again by the control circuit 5 in the original state.

Example 2. In the above-described first embodiment, when chattering of the electromagnetic contactor 4 occurs, the circuit of the electric contacts 20a, 20b is cut off by switching the bypass contact 35, and is switched to the bypass circuit 40 side. The functions of the electrical contacts 20a, 20b are lost. However, even when chattering occurs,
You may want to maintain these features. Therefore, in order to satisfy such requirements, the following measures are taken in this embodiment. FIG. 2 is a circuit diagram showing a control circuit of a refrigeration system according to Embodiments 2 and 3 of the present invention. In the figure, 40a and 40b are provided in the bypass circuit 40,
It is an alternative contact that has the same or a partial function as the electrical contacts 20a and 20b. These alternative contacts 40a, 4
As 0b, here, a bellows type mechanical contact that opens and closes at a set pressure or a bimetal type mechanical contact that opens and closes at a set temperature is used. However, a controller with the same function as the controllers 21a and 21b and a separate system is prepared,
It is also possible to use the electrical contacts that are respectively connected to these as the alternative contacts.

As described above, according to this embodiment, when the chattering occurs, the bypass contact 35 is used as the bypass circuit 4.
Electrical contact 20 that is cut off even if it is switched to the 0 side
The functions of a and 20b can be backed up by the functions of the alternative contacts 40a and 40b. In other words, the alternative contacts 40a and 40b of the bypass circuit 40 substitute the functions of the electrical contacts 20a and 20b that are interrupted when chattering occurs, and the refrigeration system can continue operating.

Embodiment 3 FIG. In FIG. 2, reference numeral 36 is an abnormal output unit that is signal-connected to the output unit 34 of the control device 31.
Therefore, when the control device 31 switches the bypass contact 35 to the bypass circuit 40 side, the control device 31 outputs a signal related to circuit switching to the abnormality output unit 36. Then, the abnormality output unit 36
Outputs an abnormal display or alarm to the effect of switching. As described above, according to this embodiment, the occurrence of chattering can be judged at a glance from the abnormal output while continuing the operation of the refrigeration system, and the user can be promptly repaired.

[0020]

As described above, the present invention has the following effects. That is, chattering is determined based on the open / closed state of the electromagnetic contactor, and if it is determined that the chattering is occurring, the chattering of the electromagnetic contactor is switched by switching to a circuit connection that bypasses the electrical contact that is relatively prone to chattering. It is possible to prevent a fatal failure of the compressor due to the above, and to continue the operation of the compressor as much as possible, and to prevent the product to be frozen from being adversely affected.

Further, by providing the alternate contact in the bypass circuit, even if the bypass contact is switched to the bypass circuit when chattering occurs, the function of the electrical contact can be backed up by the alternate contact of the bypass circuit.

Further, at the same time that the bypass contact is switched to the bypass circuit, the abnormal output section outputs a display or an alarm indicating that the switching has occurred, so that the occurrence of chattering can be judged by the user at a glance and early repair can be performed. Can be urged to the outside.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a control circuit for a refrigeration system according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a control circuit for a refrigeration system according to Embodiments 2 and 3 of the present invention.

FIG. 3 is a circuit diagram showing a control circuit of a general-purpose refrigeration system.

FIG. 4 is a circuit diagram showing a control circuit of a conventional refrigeration system.

[Explanation of symbols]

1 power bus, 2 electric motor for compressor, 4 electromagnetic contactor,
4a interlocking contact, 4b operating coil, 5 control circuit, 6
Main circuit, 10a mechanical contact, 10b mechanical contact, 2
0a electric contact, 20b electric contact, 30 current detector, 31 control device, 32 input section, 33 comparison calculation section, 34 output section, 35 bypass contact, 36 abnormal output section, 40 bypass circuit, 40a alternative contact, 40
b Alternate contact.

Claims (3)

[Claims] 1. A main circuit having an electromagnetic contactor which is formed between a power bus and a compressor electric motor and which supplies and cuts power to and from the compressor electric motor, and the electromagnetic circuit formed by branching from the main circuit. A control circuit having an electromagnetic coil for driving a contactor, two or more contacts including an electric contact connected in series with the electromagnetic coil in the control circuit, and connected in parallel to the control circuit bypassing the electric contact. A bypass circuit, a bypass contact interposed between the electric contact and the electromagnetic coil for switching circuit connection between the bypass circuit and the control circuit, and a contactor opening / closing for detecting opening / closing of the electromagnetic contactor. A detector and a controller for switching the bypass contact to the bypass circuit when the count value of the opening / closing signal from the contactor opening / closing detector exceeds a preset predetermined value. A refrigerating apparatus comprising: 2. The bypass circuit is provided with an alternative contact having a function of replacing the electric contact.
Item 3. The refrigeration apparatus according to item 1. 3. An abnormal output unit for outputting a display or alarm indicating switching when the bypass contact is switched to the bypass circuit. The refrigeration system described.