JPH0282070A - Refrigerating cycle testing method - Google Patents

Abstract

PURPOSE:To reduce time required for low voltage starting test and cooling performance test and practice both the two tests smoothly and definitely by using a variable frequency power source for a low voltage starting test power source and raising an output frequency for said low voltage starting test and cooling performance test prior to an attempt to change over the power source to the cooling performance test power source. CONSTITUTION:A low voltage starting test power source 7 comprises an inverter device for variable frequency/variable voltage. A cooling performance test power source 9 is available from a commercial power source boosted by a transformer. The low voltage starting test is carried out prior to the cooling performance test. The power supply is momentarily cut off for a short time when a relay 8 of both the tests is changed over. However, a sufficient amount of rotation energy is stored in a rotary system by a high frequency operation directly before the power supply is changed over. Therefore, this stored rotation energy can get over the loss of a drive torque induced by the cut off power supply, and carry out smooth operation based on the power source 9 for the cooling performance test with halting a compressor motor 6. Therefore, it is not necessary to install relatively long standby time during the change over time between both the tests.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Application Field) The present invention relates to a method for testing a refrigeration cycle suitable for testing a refrigeration cycle used in a refrigerator or the like on a production line.

(Prior Art) Conventionally, for example, when manufacturing a refrigerator, the refrigeration cycle used in the refrigerator is tested at the final stage of the refrigeration cycle assembly line. The test includes a cooling performance test in which the compressor motor for the refrigeration cycle is operated at the rated input voltage to test its basic cooling characteristics, and a low voltage below the rated input voltage is applied to the compressor motor. It includes a low voltage start-up test that tests the start-up characteristics of the compressor motor. In this case, conventionally, the cooling performance test and low voltage startup test are conducted separately, and specifically,
After the refrigeration cycle is assembled, it is operated to perform a performance test, and then the refrigeration cycle is stopped and a low voltage startup test is conducted.

(Problem to be solved by the invention) However, in the above conventional method, after the cooling performance test is completed,
The low voltage startup test can only be performed after the compressor motor has been stopped and the refrigerator has been left on the inspection line for a relatively long time (for example, about 20 minutes). This is because in order to accurately evaluate the starting characteristics of a compressor motor, it is necessary to perform a low-voltage starting test under conditions where the internal pressure of the refrigeration cycle is balanced. This is because it is necessary to wait until the gas pressure stabilizes. For this reason, in the conventional method, the inspection line must be made quite long, which becomes an obstacle to the effective use of space within the factory, and also causes a large number of refrigerators waiting to be tested on the inspection line, which reduces productivity. This was causing deterioration.

In order to deal with this, contrary to the conventional method, a low voltage startup test is first performed, followed by a cooling performance test in which the balance/imbalance of the internal pressure of the refrigeration cycle at the time of startup is not a problem. can also be considered. However, with this method, the drive torque of the compressor motor is quite small during the low-voltage start-up test, so the compressor motor will stop due to a momentary power outage when switching from the power supply for the low-voltage start-up test to the power supply for the cooling performance test. As a result, a smooth transition to the cooling performance test may not be possible.

The present invention has been made in view of the above circumstances, and its purpose is to shorten the time required to conduct both the low voltage start-up test and the cooling performance test17, thereby shortening the line length required for the test. Moreover, it is an object of the present invention to provide a refrigeration cycle testing method that can smoothly and reliably execute both tests.

[Structure of the Invention] (Means for Solving the Problems) The refrigeration cycle testing method according to the present invention switches the power supply after performing a low voltage startup test to continue the cooling performance test, and also performs a low voltage startup test. A variable frequency power supply is used as the test power supply, and the output frequency of the low voltage startup test power supply is increased immediately before switching to the cooling performance test power supply.

(Function) Since a low voltage startup test is first performed, the refrigerant gas pressure within the refrigeration cycle is stable at the start of the test, and the startup characteristics can be appropriately evaluated. In addition, since we continue to conduct cooling performance tests after low-voltage start-up tests in which the balance or imbalance of the internal pressure of the refrigeration cycle at startup is not a problem, it is possible to start cooling performance tests immediately after low-voltage start-up tests. This reduces the time required to complete both tests.

Moreover, since a variable frequency power supply is used as the power supply for low voltage startup tests, and the output frequency of the power supply for low voltage startup tests is increased immediately before switching the power supply, the rotational speed of the compressor motor As a result, even if there is a drop in torque due to a momentary power outage that inevitably occurs when switching the power source, the flywheel effect can overcome this.

(Example) FIG. 3 shows a schematic plan view of a manufacturing line for refrigerators, for example. In the figure, reference numeral 1 denotes a refrigeration cycle assembly line, which consists of a slat conveyor that moves in the direction of the arrow in the figure, and includes the assembly of the refrigerator body 2 and the assembly of the refrigeration cycle to the refrigerator body 2 on this conveyor. An assembly process is performed. Particularly in this case, at the final stage of the assembly process, a process of filling the refrigerant gas into the refrigeration cycle is performed to complete the refrigeration cycle. Reference numeral 3 denotes a first inspection line that inspects the refrigerator bodies 2 while conveying them after passing through the assembly line 1. This consists of a slat conveyor that moves in the direction of the arrow in the figure. A start-up test and a cooling performance test are performed in sequence. After passing through each of the above tests, the refrigerator body 2 was subjected to a final assembly process and a shipping inspection process on a final assembly line (not shown) and on a second inspection line 4 moving in the direction of the arrow in the figure. Afterwards, it is shipped via the packaging and shipping line 5. Note that the first and second inspection lines 3 and 4 are installed in a constant temperature atmosphere.

Now, in the low voltage starting test conducted on the first inspection line 3, the low voltage starting test power supply is applied to the compressor motor 6 (shown in FIG. 2) for the refrigeration cycle provided in the refrigerator body 2. By applying a low voltage below the rated input terminal to the compressor motor 7, the starting characteristics of the compressor motor 6 are tested. For example, if the rated input terminal of the refrigerator is 220V, 150 to 170V (50
When the input voltage of H7) is applied, it is determined whether the compressor motor starts normally or not.

In addition, the cooling performance test, which is also conducted on the first inspection line 3, connects the compressor motor 6 to the cooling performance test power supply 9 by switching the relay 8, and operates at the rated input terminal 220V (60Hz). It is used to test various characteristics of the refrigeration cycle. In this embodiment, the low voltage startup test power supply 7 has 1.
It is composed of a variable voltage inverter device, and the cooling performance test power source 9 is obtained by boosting the voltage from a commercial power source using a transformer.

Therefore, in this embodiment, the above-mentioned low voltage start-up test is conducted prior to the cooling performance test, and is started when a predetermined period of time has elapsed after the refrigerant gas was filled into the refrigeration cycle. (time 1+ in Figure 1)
). Of course, the compressor motor 6 is not operated before the low voltage startup test is started. Therefore, the refrigerant gas pressure in the refrigeration cycle does not become significantly unbalanced as it does immediately after the compressor motor 6 stops, and is in a stable state, making it possible to appropriately evaluate the startup characteristics of the refrigeration cycle. be. Note that the temperature of the refrigeration cycle at this time is not the temperature of the first inspection line 3, but is adjusted to the temperature of the assembly line 1. Therefore, the voltage applied to the compressor motor 6 is adjusted based on the difference between the temperature of the assembly line 1 (that is, the actual temperature of the refrigeration cycle) and the temperature for performing the legal low voltage start-up test. There is.

Now, when the test ends after 5 to 15 seconds have passed from the start of the low voltage startup test (time tz in Figure 1), the output voltage of the low voltage startup test power supply 7 is increased to, for example, 240V, and this When time t is reached after 1 second elapses, for example, from 02 to 1 second, the output frequency of the low voltage starting test power supply 7 is increased to, for example, 70H2. This increases the rotational speed of the compressor motor 6 and accumulates a large amount of rotational energy. When this state reaches time t after reading for about 1 to 5 seconds, the relay 8 is activated and the power source for the compressor motor 6 or the power source for the low-voltage start-up test is switched from the power source 7 for the cooling performance test to the power source 9 for the cooling performance test. The motor 4 is operated at a rated voltage and frequency of 220V and 60H2. However, at the moment when the relay 8 switches, it takes a short time (several liters).
The power supply is cut off for 15 to several tens of seconds). However, since sufficient rotational energy is stored in the rotating system due to the high-frequency operation immediately before switching between the 7 and 7 power sources, the flywheel effect can overcome the loss of drive torque due to power cutoff, and the compressor motor 6 stops. The cooling performance test power supply 9 can be operated smoothly without any trouble.

According to this embodiment described above, a low voltage startup test is first performed with the internal pressure of the refrigeration cycle balanced, and then a cooling performance test is performed in which the balance/unbalance of the internal pressure of the refrigeration cycle is not a problem. This eliminates the need for a relatively long waiting period between the two tests.
A cooling performance test can be performed immediately after the low voltage start-up test is completed. As a result, the time required to complete both tests can be shortened, and the line length for inspection can be shortened by that amount, which in turn leads to more effective use of space within the factory and improved productivity. be able to. Furthermore, in this case, since the low voltage startup test is conducted while the internal pressure of the refrigeration cycle is decreasing, it goes without saying that the startup characteristics can be evaluated appropriately and accurately. Moreover, before switching from the low-voltage start-up test power supply 7 to the cooling performance test power supply 9 in order to proceed to the cooling performance test, the output frequency of the low-voltage start-up test power supply 7 was increased, so that Momentary power outages can be overcome by the flywheel effect, allowing a smooth transition from low voltage startup tests to cooling performance tests. In addition, in this example, especially low? Before increasing the output frequency of the Ii pressure startup test power supply 7 from 50H7 to 70H2, the output voltage is increased, thereby preventing the compressor motor 6 from stalling due to a sudden increase in slip when changing the frequency. can do. However, depending on the capacity of the compressor motor, it is not necessarily necessary to increase the output voltage in advance as described above, and the output voltage may be increased in conjunction with frequency switching. Further, the frequency does not necessarily have to be switched all at once, but may be increased stepwise in steps of 5H2, for example from 50H7 to 70H2.This is effective in preventing the above-mentioned stall situation.

In addition, the present invention is not limited to the embodiments described above and shown in the drawings, and can be applied, for example, to testing not only refrigeration cycles for refrigerators but also refrigeration cycles for air conditioners, within the scope of the invention. It can be implemented with various modifications.

[Effects of the Invention] As is clear from the above explanation, according to the present invention,
After performing the low-voltage start-up test, we switched the power supply and continued the cooling performance test.We also increased the output frequency of the low-voltage start-up test power supply immediately before switching the power supply, so both tests This has the excellent effect of shortening the time required to perform the test, and making use of the flywheel effect to smoothly and reliably transition from the low voltage startup test to the cooling performance test.

[Brief explanation of the drawing]

The drawings are for explaining one embodiment of the present invention.
The figure is a waveform diagram showing the voltage and frequency applied to the compressor motor, Figure 2 is a block diagram showing the electric circuit for low voltage start-up tests and cooling performance tests, and Figure 3 is a schematic diagram of the production line. In the figure, 1 is the assembly line, 2 is the refrigerator body, 3 is the first inspection line, 4 is the second inspection line, 6 is the compressor motor, 7 is the power supply for low voltage startup test, and 8 is the relay 9 is a power supply for cooling test, and 10 is a relay drive circuit. U Fig. 2 Fig. 1

Claims (1)

[Claims] 1. A cooling performance test in which the compressor motor for the refrigeration cycle is operated at the rated input voltage to test various characteristics of the refrigeration cycle, and the compressor motor is started by applying a low voltage below the rated input voltage to the compressor motor. When conducting a low voltage starting test to test the characteristics, the power supply is switched after the low voltage starting test and the cooling performance test is continued.
Using a variable frequency power supply as the power supply for the low voltage startup test,
A method for testing a refrigeration cycle, characterized in that immediately before switching to a power source for cooling performance testing, the output frequency of the power source for low voltage startup testing is increased.