JPH05272810A - Air blowing motor control circuit for electrical hot air blower - Google Patents

Abstract

PURPOSE:To prevent a power consumption greater than that of design specification from being increased in the case that a ceramic heater constructed by a positive characteristic thermistor has a low internal resistance under a low temperature state and cold air is sent to the ceramic heater due to the consumption of the electrical power. CONSTITUTION:A resistor 4 (for example, a resistor of 200OMEGA) is arranged in series with an air blowing motor 2 for producing hot air arranged in parallel with a ceramic heater 1 and a temperature switch 5 which is turned ON at 10 deg.C or higher, for example, is arranged in parallel with the resistor 4. Due to this fact, in the case that with the air blowing motor 2 is short-circuited by the temperature switch 5, does not influence the number of revolution of the air blowing motor 2 and in turn, if the temperature is 10 deg.C or lower the temperature switch 5 is turned OFF, the air blowing motor 2 is connected in series with the resistor 4, the motor is influenced by the resistor 4 so as to decrease the number of revolution of the air blowing motor 2, resulting in that the power consumption at the low temperature is not abnormally increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric warmer for heating by utilizing the characteristics of a positive temperature coefficient thermistor.

[0002]

2. Description of the Related Art In a conventional electric warmer, a positive temperature coefficient thermistor is used as a heating element, and since the positive temperature coefficient thermistor is made of ceramic, a heater for heating is called a ceramic heater. FIG. 3 shows a conventional example of an electric warmer using a ceramic heater. When the ceramic heater 11 and the blower motor 12 are energized, the ceramic heater 11 generates heat and the indoor air sucked into the blower becomes warm air. It is returned to the room from the hot air outlet.

Generally, one or a plurality of ceramic heaters 11 are provided in accordance with a desired capacity, and the changeover switch 14 generally switches the intensity of heat generation.

Since this type of ceramic heater has a positive characteristic, when the temperature rises due to heat generation and the temperature rises, the internal resistance increases and the amount of energization decreases, and even if the air volume of the blower applied to the ceramic heater is constant, the temperature will rise. The current flowing through the heater fluctuates depending on the height of the device, and the 1200 W specification product sometimes energized up to 1300 to 1350 W at a low temperature.

[0005]

As described above, when used at a high temperature when the room temperature is low, for example, the 1200 W specification may increase the energization amount to 1300 to 1350 W, which is usually the 12 A specification. This means that a current of 13 A or more should flow. Therefore, there are problems that the durability of the product is reduced, the breaker blows out, it cannot be used, and the electricity cost rises due to the increase in power consumption. is there.

[0006]

In order to solve the above problems, the present invention provides a resistor in series with a blower motor, a temperature switch connected in parallel with the resistor, and a temperature switch at a certain temperature or higher. When turned on, the blower motor is normally energized directly, and when the temperature is low, the temperature switch is turned off, and the rotation speed of the motor is reduced by the action of resistance, and the amount of blown air is reduced to keep the ceramic heater at a high temperature. It stabilizes the flowing current.

That is, in an electric warmer having an ON-OFF switch 3 in series in a parallel circuit of a ceramic heater 1 and a blower motor 2, a resistor 4 is provided in series with the blower motor 2 and the resistor 4 O in parallel above a certain low temperature
A temperature switch 5 for turning on is provided to control the blower motor of the electric warmer.

[0008]

[Function] The ON-OFF switch 3, which is the main switch, is turned off.
N, the electricity is ceramic heater 1 and blower motor 2
Flow to. The blower motor 2 rotates the blower fan to blow indoor air to the ceramic heater 1, and the indoor air takes away heat from the ceramic heater 1 and replaces it with warm air, thereby forming an electric warmer that blows warm air into the room. ..

The blower motor 2 is provided with a resistor 4 in series, and a temperature switch 5 is provided in parallel with the resistor 4 and the temperature switch 5 has a constant low temperature (for example, 10).
It turns off below ℃) and turns on above.
When it is OFF, the resistance 4 is applied to the blower motor 2 circuit to reduce the rotation speed of the blower motor 2, and when it is ON, the blower motor 2 is directly powered and the influence of the resistor 4 disappears. It has the effect that the rotation speed does not decrease.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an electric circuit diagram showing an embodiment of the present invention, in which 1.1a is a ceramic heater composed of a thermistor having a positive temperature characteristic, and 2 are one or a plurality of ceramic heaters connected in parallel. Blower motors 2a connected in parallel with the ceramic heaters 1a and 1a are blower fans rotated by the blower motor 2. Reference numeral 6 denotes a changeover switch connected in series to one ceramic heater 1a connected in parallel. By operating the changeover switch 6, a desired heat generation amount is selected.

Reference numeral 3 denotes an ON-OFF switch which is connected in series with a parallel circuit of the ceramic heaters 1a, ... Or the blower motor 2 and serves as a main switch. Reference numeral 4 is a resistance provided in series with the blower motor 2, and a resistance of about 20Ω is used. Reference numeral 5 is a temperature switch connected in parallel with the resistor 4. For example, when the room temperature is 10 ° C., the above is ON, the following is OF
It becomes F.

When the temperature switch 5 is OFF, the blower motor 2 is energized via the resistor 4 to lower the rotation speed of the blower motor 2. When the temperature switch 5 is turned on, the blower motor 2 is not affected by the resistor 4, and the power source is directly connected to the blower motor 2 to rotate at high speed. Reference numeral 7 is a high limit switch that senses a high temperature and turns off the electric circuit when the ceramic heaters 1a, 1a ,.

FIG. 2 is an overall constitutional view showing an embodiment of the present invention, which is provided with respective constitutions of reference numerals shown in the electric circuit diagram of FIG. 1, and 8 is a hot air outlet for warm air passing through the heater 1. , 9 are frames of the ceramic heater.

FIG. 3 shows an example of a conventional electric circuit, in which 11 and 11a are ceramic heaters composed of thermistors having positive characteristics, 12 is a blower motor provided in parallel with the heaters 11 and 11a, and 13 is Ceramic heater 11 ・ 11
a and a switch for connecting the parallel circuit of the blower motor 12 in series to turn on and off the electric circuit, 14 is a changeover switch individually provided in one heater 11a in the case of providing a plurality of heaters 11, and 15 is a heater This is a high limit switch that turns off the electric circuit by sensing high temperature when abnormal heating occurs.

[0015]

As described above, the electric warmer using the ceramic heater 1 of the present invention has the temperature switch 5 and the resistor 4 which are turned off when the room temperature becomes low (for example, 10 ° C.).
By connecting the parallel circuit of 1 to the blower motor 2 in series, it is possible to prevent the blower motor 2 from being connected in series with the resistor 4 at a low temperature to reduce the rotation speed and continuously increase the power consumption of the ceramic heater 1. It is a thing.

Therefore, it becomes possible to maintain the constant power consumption determined by the design specification, and the design specification value (for example, 12 A).
The above current does not impair the durability of the product and no extra design quality is required.

Further, since there is no unexpected power consumption, it is possible to save electricity bills and prevent accidents such as breaker flying.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a product embodying the present invention.

FIG. 3 is an electric circuit diagram showing an example of a conventional example.

[Explanation of symbols]

 1 Ceramic heater 2 Blower motor 3 ON-OFF switch 4 Resistance 5 Temperature switch

Claims (1)

[Claims] 1. An electric warmer having an ON-OFF switch 3 in series in a parallel circuit of a ceramic heater 1 and a blower motor 2 is provided with a resistor 4 in series with the blower motor 2. A blower motor control circuit for an electric warmer provided with a temperature switch 5 which is turned on in parallel at a constant low temperature or higher.