SU1707675A1 - Electric heating control device for outdoor metal-clad switcher - Google Patents

Abstract

The invention relates to electrical engineering and can be used in complete switchgears for outdoor installation. The purpose of the invention is to increase reliability by increasing the efficiency of electrical heating. The device contains four voltage dividers, two of which consist of a constant resistor and a resistive temperature sensor of the heated apparatus. The outputs of the dividers are connected to three comparators. The outputs of the comparators through the OR element are connected to the executive body that turns on and off the heating. 1 il.

Description

The invention relates to electrical engineering, in particular to complete switchgears for outdoor installation (KRUN) b-U kB.

The purpose of the invention is to increase reliability by increasing the efficiency of electrical heating.

The drawing shows a block diagram of the proposed device.

The device contains the first voltage divider 1 consisting of series-connected constant resistor 2 with resistance RI and a resistive sensor 3 of the temperature of the heated apparatus with resistance RKP, the second voltage divider 4 consisting of series-connected constant resistor 5 with resistance R2 resistive sensor 6 of the temperature of the metal housing of the housing with resistance RM, the first

7. the second 8 and third 9 comparators, the third voltage divider 10. consisting of series-connected DC resistors 11 and 12 with resistances of CH3 and R4, respectively, the fourth voltage divider 13, consisting of series-connected DC resistors 14 and 15 with resistances RS and RG, respectively, an element OR 16 and an executive body 17.

The non-inverting inputs of the first 7, second 8, and third 9 comparators are connected to the output of the first voltage divider 1, and the inverting outputs of the second 8 and third 9 comparators are connected respectively to the outputs of the third 10 and fourth 13 voltage divider.

The outputs of the first 7 and second 8 Comparators are connected to the inputs of the element OR 16, the output of which is connected to the input of the IC (

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Complementary body 17, and the output of the third comparator 9 is connected to the strobe input of the first 7 and second 8 comparators.

The device works as follows.

Let the outside air temperature be above -20 ° C. The resistances of the resistors in dividers 1 and 4 are chosen so that

cr

Ri + Ra + RM

only if the temperature of the body of the heated apparatus Tcr is higher than the temperature of the metal case of the cabinet KRUN TMK by 3.4 ° C. If Tmc TCr, then

"R

Ri + R2 + RMK

In doing so, the voltage at the non-inverting input of the comparator 7 becomes greater than that at the inverting. The comparator 7 is switched to a logical unit, which through the element OR 16 enters the input of the actuator 17, which turns on the heating. As soon as the temperature Tcr exceeds the temperature Tmk by 3.4 ° C as a result of heating, comparator 7 switches to a logical zero and turns off the heating systems.

When the outside air temperature drops below -20 ° C, if it drops below -20 ° C, the voltage removed from the third divider 10 and the non-inverting input of the second comparator 8 coming to us becomes less than the voltage at its non-inverting input those. condition is met

R3 + R RI + RKP

In this case, the comparator 8 is switched to a logical unit, which through the element OR 16 enters the input of the actuator 17, including the heating system. As it heats up, the resistance of the resistive temperature sensor 3 decreases. In this case, the voltage on the inverting comparator 8 switches to a logical zero and turns off the heating system.

When the heaters are on, if the Tire temperature becomes higher than + 40 ° C. Then the third comparator 9 is triggered, since at its inverting input the voltage removed from the fourth divider 13 starts to exceed the voltage at the non-inverting input, i.e. condition is met

Re

R

J

Rs + Re Ri + RKP

In this case, a logical zero appears at the output of the comparator 9, arriving at the gating inputs of the first 7 and second 8 comparators, which, in turn, causes them to switch to a logical zero and

0 off the heating system. The third comparator 9 ensures the prohibition of overheating of the devices installed in the metal-clad switchgear, both during the normal operation of the first 7 and second 8 comparators, as well as when the settings of their operation are accidentally violated during operation.

Thus, the invention allows to provide the required temperature and humidity conditions in the internal volume.

0 KRUN. which increases reliability and makes heating more efficient.

Claims (1)

Claims of the Invention A device for controlling an electrical roar of apparatus of a metal cabinet of an outdoor switchgear assembly containing a dat-. The temperature of the apparatus to be heated and the actuator are distinguished so that, in order to increase reliability by increasing the efficiency of electrical heating, it is equipped with a temperature sensor of the metal cabinet body, four resistive dividers for 5 times with three comparators and an OR element. the first voltage divider is made of a series-connected constant resistor and a temperature device made by a resistive temperature sensor of the heated apparatus, the second voltage meter is made of a series-connected constant resistor and a temperature sensor of the metal cabinet body, and the non-inverting inputs of the first, second and The third comparator is connected to the output of the first voltage divider, the inverting input of the first comparator is connected to the output of the second voltage divider, and the inverter The secondary inputs of the second and third comparators are connected respectively to the outputs of the third and fourth voltage dividers, while the outputs of the first and second comparators are connected to the inputs 5 of the OR element, the output of which is connected to the input of the executive body, and the output of the third comparator is connected to the inputs of the gating of the first and second comparators. sixteen L