JPS589753Y2 - Defrost control circuit - Google Patents

Description

[Detailed explanation of the invention] This invention relates to a defrosting control circuit for a refrigerator, and is a general-purpose
It has a fail-safe function by combining a 4-hour timer and an auxiliary relay.

The conventional defrost timer has a dial with one cycle every 24 hours, and the defrost start time can be set at intervals of 1 to 2 hours, and the defrost time can be set at intervals of 2 minutes, ranging from 2 to 110 minutes.

Therefore, it was possible to set a time approximately equal to the time required for defrosting.

Furthermore, since the defrosting time changes depending on the outside air temperature and temperature, there is a drawback that the defrosting time must be changed depending on the seasons.

To solve this problem, a system has been developed and is currently in use that detects the end of defrosting using a signal from a thermostat or pressure switch, and forcibly switches the contacts of the defrost timer mechanically.

That is, as shown in FIG. 1, an electromagnetic contactor 4 for compressor operation and a defrost heater 5 are connected to the cooling contact 3a and the defrost contact 3b of the changeover switch 3 by the timer motor 2 of the defrost timer 1, respectively. The defrost heater 5 is energized by the closing of the defrost end thermostat 6, and is activated by the changeover switch 3.
A solenoid coil 7 is connected in parallel to mechanically return the defrost contact 3b to the cooling contact 3a.

Also, there are currently general-purpose 24-hour timers on the market that can turn on and off at 155-minute intervals, but at 15-minute intervals, the time range (15, 30
, 45 minutes), making it unsuitable for defrosting purposes.

The present invention provides a defrost control circuit equipped with a fail-safe function that can be used as a defrost timer by combining this general-purpose 24-hour timer and an auxiliary relay.

Below, the present invention will be explained with reference to the embodiment shown in Fig. 2.1
0 is a timer, 11 is a time switch that is switched at fixed intervals by the operation of the timer motor 12, and the cooling contact 11a of the switch is an electromagnetic contactor 13 for operating the compressor, and the defrost contact 11b is a time switch for indicating the end of defrosting. An auxiliary relay 15 with a sensing thermometer 14 interposed therebetween and a first relay contact 15a of the auxiliary relay.
The defroster heaters 16 are connected in parallel.

The first relay contact 15a of the auxiliary relay 15 is connected in parallel with the defrosting end sensing thermometer 14 to perform a self-holding function, and the second relay contact 15b is connected in parallel with the cooling contact 11a of the time switch 11. There is.

Next, the operation will be explained. In the illustrated state, the time switch 11 is in contact with the cooling contact 11a, and the compressor electromagnetic contactor 13 is turned on and in a cooling operation state.

When the set pin of the timer 10 is turned on, the time switch 11 switches to the defrost contact 11b, and the defrost heater 1 is switched on.
6 is activated to change from the cooling state to the defrosting state.

When the defrosting is finished, the defrosting completion detection thermo 14 is set to 0.
becomes N, the auxiliary relay 15 operates, and the first relay contact 15
a and second relay contact 15b are both energized.

As a result, the compressor operating electromagnetic contactor 13 is turned on, the defrost heater 16 is turned off, and the auxiliary relay 15 is self-held, so that the defrosting operation is forcibly switched to the cooling operation.

Even if the defrost end detection thermo 14 turns OFF midway, the defrost contact 1 will be activated depending on the OFF time of the Sera I pin of the timer 10.
The auxiliary relay 15 is self-holding until the contact 1b switches to the cooled contact 11a.

As mentioned above, the defrost control circuit according to the present invention is assisted via a defrost end thermostat on the defrost operation side of the switching contact that switches between cooling operation and defrost operation at regular intervals due to the operation of a timer.
the first contact of the auxiliary relay is switched in series with the defrosting means or in parallel with the defrost end thermostat, and the second contact of the auxiliary relay is connected in parallel with the switching contact of the timer on the cooling operation side. Therefore, the defrost operation can be switched from the defrost operation to the cooling operation by the defrost end thermometer regardless of whether the defrost timer is in one hour, and a dedicated defrost timer can be set simply by combining an auxiliary relay with a general-purpose 24-hour timer. It is possible to provide a defrost control circuit that performs the same function as the one used.

Furthermore, since a general-purpose timer can be used, the cost is low, and the manufacturing cost can be reduced.

[Brief explanation of drawings]

FIG. 1 is a conventional defrosting control circuit diagram, and FIG. 2 is a defrosting control circuit diagram of the present invention. 10...Timer, 11...Time switch, 13...Magnetic contactor for compressor operation, 1
6...Defrost heater, 15...Auxiliary relay, 14...Defrost completion detection thermo, 15a...
...First relay contact.

Claims (1)

[Scope of utility model registration request] An auxiliary relay is connected via a defrost end thermostat to the defrosting operation side of a switching contact that switches between cooling operation and defrosting operation at fixed intervals due to the operation of a timer, and the first contact of the auxiliary relay is connected to the defrosting means. A defrost control circuit characterized in that the defrost control circuit is connected in series or in parallel with the defrost end thermometer, and the second contact of the auxiliary relay is connected in parallel to the switching contact of the timer on the cooling operation side.