JPH0247420Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a control device for a fan motor, particularly a control device for a fan motor for an air-cooled condenser in a refrigerator such as an ice maker or an air conditioner.

Generally, when the temperature of the outside air to which an air-cooled condenser is exposed changes beyond a predetermined design value, the motor rotation speed of the heat dissipation fan installed near the air-cooled condenser must change accordingly. If so, the condenser temperature fluctuates, making it impossible to maintain the desired condenser outlet temperature.

In order to eliminate this inconvenience, the special public
In Publication No. 37539 and Japanese Utility Model Publication No. 48-43746, the rotation speed of the fan motor is lowered at low temperatures where a small cooling capacity is required, and the rotation speed of the fan motor is increased at high temperatures requiring a large cooling capacity to achieve the desired condenser. Measures are taken to maintain outlet temperature. In particular, the former Japanese Patent Publication No. 48-37539 discloses a phase control circuit as a specific means for controlling the fan motor.

However, in a fan motor control device using such a conventional phase control method, the torque at low speed rotation at low temperatures is small as described above, resulting in unstable and uneven rotation, and continuously variable speed control is difficult. Although it is possible, it has the disadvantage that a starting compensation circuit must be added. Moreover, when the rotational speed decreases, control becomes difficult, and it is necessary to adjust variations in temperature sensing elements such as thermistors.

In view of the shortcomings of the prior art, the present applicant filed Utility Application No. 127678/1983 (control device for fan motor).
We have provided an improved idea. That is, this improved idea corresponds to the broken line block A in FIG. and is connected. On the other hand, commercial power supply 1 is a transformer
It is also connected in parallel to the primary winding of the TR, and the transformer
The secondary winding of the TR is divided into two parts, one of which is connected to the rectified power supply 3 and the other to the synchronous pulse generator. The synchronous pulse generator 4 is connected to a frequency divider 5 (means described later are inserted in FIG. 1 for improvements in the present invention), and the frequency divider 5 is connected to an amplifier 6. The amplifier 6 is connected to a control (trigger) terminal of the bidirectional conduction switch element 2. Incidentally, both the frequency divider 5 and the amplifier 6 are supplied with DC power from the rectifier power supply 3, and a temperature sensing element (for example, a thermistor) TH is connected in parallel to the bidirectional conduction switch element 2.

The invention of the present applicant's earlier application shown in Block A is such that a synchronizing pulse generator 4 that generates one synchronizing pulse every half cycle of the commercial power supply 1 is connected to a frequency divider 5. The synchronizing pulse is frequency-divided (in this case, by an odd number, for example, 1/5) into a waveform, which triggers the bidirectional conduction switch element 2 via the amplifier 6. Therefore, the fan motor
The frequency of the voltage applied to the FM is an odd-numbered fraction of the frequency of the commercial power source 1, and since the fan motor FM is an induction motor, the impedance decreases, the current increases, and the torque increases.

When the outside air temperature (ambient temperature) exceeds a predetermined temperature, the temperature sensing element TH closes, shorts the bidirectional conduction switch element 2, disables it, and controls the fan motor to rotate at high speed at the commercial frequency. There is.

Generally, in an ice maker, etc. that includes an air-cooled condenser and a fan motor for cooling the air-cooled condenser, and performs ice-making operation and de-icing operation repeatedly, the fan motor is turned on in the early stages of ice-making operation to increase the cooling capacity. It is preferable to strongly cool the condenser by controlling the rotation speed of the motor to be high. Also, in the latter stages of ice-making operation when ice has been formed, the condenser temperature becomes low, so the rotation speed of the fan motor is increased. It has been found that it is preferable to perform control such that the temperature is lowered. Also, from the perspective of deicing operation, which removes the generated ice, this deicing operation is performed by bypassing the high temperature refrigerant from the compressor and passing it through the cooler, so the discharge temperature of the compressor It is preferable that the rotation speed of the fan motor be high, and therefore, it is preferable that the rotation speed of the fan motor be low in the latter half of the ice-making operation.

Considering the ideal operating characteristics of an ice maker, etc., and considering the fan motor control device shown in broken line block A in Fig. 1, the condenser temperature is high at the beginning of ice making operation, so for example, The temperature sensing element TH installed in the air-cooled condenser senses the relatively high ambient temperature and closes, causing the fan motor to rotate at full speed. The temperature element TH senses a relatively low ambient temperature and opens, thereby causing the fan motor to rotate at a low speed. Thus, the circuit of block A in Figure 1 is designed to provide ideal operating characteristics. It turns out that this is preferable. It can also be seen that the circuit of block A in FIG. 1 is suitable for deicing operation as well, since the high temperature refrigerant is directly bypassed from the compressor to the cooler after deicing operation begins.

However, regardless of the operating status of the condenser, if the outside air temperature (ambient temperature) itself is comparable to or lower than the temperature during the latter stages of ice-making operation, the temperature sensing element TH will not sense the low outside air temperature. It will remain open from the beginning. In this way, when the outside air temperature is low, the fan motor FM always rotates at a low speed, and especially when ice making starts, the compressor load increases and the condenser outlet temperature rises, so that the specified cooling capacity is not achieved. This caused problems with the durability of the cooling system itself.

The present invention maintains the above-mentioned advantages of the prior invention and further solves the problem at the start of ice making. A control device for a fan motor is provided, which allows the fan to rotate at full speed for a certain period of time, and then maintains an operating state commensurate with the ambient temperature.
This is accomplished using one timer.

The present invention uses a timer (for example, an IC timer) 7 in addition to the earlier invention regarding block A in FIG.
The output signal of the timer 7 and the pulse from the frequency divider 5 are supplied to the amplifier 6 via the OR gate 8 to trigger the bidirectional conduction switch element 2. The operation of the timer 7 is started by an ice making start signal (usually generated when the power is turned on or when the water tray of the ice maker returns to a predetermined position after deicing is completed).

To explain the operation of the fan motor control device of the present invention shown in FIG. It is sending a pulse. On the other hand, since the timer activated by the ice-making start signal is designed to generate a logic "1" signal for a predetermined period of time (approximately 6 to 7 minutes), the bidirectional conduction switch element 2 is activated during this predetermined period of time. Since conduction continues, the frequency-divided pulse is disabled and the fan motor FM rotates at high speed at the commercial frequency.

After the predetermined period of time has elapsed, the output of timer 7 becomes logic "0", and the divided pulse now triggers the bidirectional conduction switch element at the divided lower frequency, causing low speed rotation as described above. It is done. Further, when the ambient temperature reaches a predetermined value or higher, the temperature sensing element TH closes to short-circuit the bidirectional conduction switch element 2, causing the fan motor FM to rotate at high speed.

Incidentally, the timer 7 is reset by a predetermined reset signal when an ice making timer (not shown) has elapsed for a predetermined time.

FIG. 2 shows the characteristics (A) of the condenser outlet temperature and ice making time of the fan motor control device of the present invention and the characteristics (B) of the invention of the prior application.

As described above, and as is clear from the graph of FIG. 2, according to the fan motor control device of the present invention, by rotating the fan motor at high speed for a predetermined period of time from the start of ice making, the compressor at the start of ice making can be It is possible to suppress an increase in load and lower the condenser outlet temperature, and also to suppress power consumption, which is advantageous in terms of energy saving. (For example, in about 7 to 8 minutes after starting ice making, the configuration devised by the earlier application produces 316W,
According to the configuration of the present invention, a power consumption value of 286W has been experimentally obtained. ) This means that even if the condenser (not shown) is clogged, a steady condenser temperature and pressure can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram of a fan motor control device according to the present invention, and FIG. 2 is a graph showing the condenser outlet temperature vs. ice making time characteristics according to the present invention and the prior invention. 1... Commercial power supply, 2... Bidirectional conduction switch element, 4... Synchronous pulse generator, 5... Frequency divider, 6
...Amplifier, 7...Timer, 8...Or gate.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In an operation control system for an ice maker that alternately performs ice-making operation and de-icing operation, including an air-cooled condenser and a fan motor for cooling the air-cooled condenser, a bidirectional conduction switch element connected in series with the fan motor and connected between both ends of a commercial power source together with the fan motor; a synchronous pulse generator that generates one synchronous pulse every half cycle; a frequency divider connected to the synchronous pulse generator that divides the period of the synchronous pulse; a timer that receives an ice-making start signal and generates a logic "1" signal for a predetermined period of time after receiving the ice-making start signal; and a timer that is connected in parallel with the bidirectional conduction switch element and closes when the ambient temperature is above a predetermined temperature. a temperature sensing element that short-circuits the bidirectional conduction switch element; an OR gate that inputs signals from the frequency divider and the timer and outputs them to a control terminal of the bidirectional conduction switch element via an amplifier; A fan motor control device comprising: (2) The control device for a fan motor according to claim 1, wherein the temperature sensing element is a thermistor, and the thermistor is installed in the air-cooled condenser to detect the ambient temperature. (3) The control device for a fan motor according to claim 1 or 2, wherein the bidirectional conduction switch element is a triax.