JPS6013246Y2 - blower device - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an improvement of a blower with a built-in electric motor used, for example, in a dryer.

[Technical background of the invention and its problems] Conventionally, hot air in a dryer that uses combustion heat is obtained by applying air from a blower to the furnace.

Dryers are generally used for multiple purposes, so some blowers can carry a wide range of loads.

There is no problem with an external drive type, but with a blower with a built-in electric motor, the drive motor is cooled by the blower's own air, so a blower with the characteristics shown in Figure 6 has a low flow rate and is difficult to load. The drawback is that the current increases and overheating occurs.

Furthermore, when the power supply voltage changes, there is a risk of overheating in each blower load, that is, in the cooling air volume.

Generally, the load of the blower can be protected by detecting the pressure, but the only way to protect the motor temperature from rising in relation to the voltage of the drive motor, that is, the power supply voltage, is to use a temperature sensor built into the motor.

[Purpose of invention]

This invention was developed in consideration of the above circumstances,
The purpose is to provide a blower device that can reliably protect the motor at its operating limits against voltage drop to the motor and static pressure of the blower.

[Summary of the idea]

In order to achieve the above object, the present invention provides a blower with a built-in motor that is driven by a drive motor supplied with power from a power source and cools the drive motor by its own air blowing. an overcurrent relay element that trips the main circuit of the drive motor in response to an increase in current due to a voltage drop; and an overcurrent relay element that is displaced in response to a change in the blowing pressure of the blower to facilitate tripping of the overcurrent relay element. It is characterized by comprising a protection relay made of a pressure change relay element.

[Example of idea]

Hereinafter, an embodiment of the present invention shown in the drawings will be described.

FIG. 1 shows an example of a configuration in which a blower device according to the present invention is applied to a dryer.

In the figure, a dryer 1 cools a drive motor 3 by blowing air as shown by the arrow from a blower 2, and passes it through a furnace 4 having a heat source such as a burner 4, where it becomes hot air and blows hot air over the objects to be dried on a drying platform 6. It is designed to dry.

FIG. 2 shows an example of the configuration of the protection relay in the blower device, in which the same parts as in FIG. 1 are denoted by the same reference numerals.

In the figure, a blower 2 detected by a pressure sensor (not shown)
The protection relay 8 detects the air blowing pressure via the pressure detection cable 7.
At the same time, a power supply voltage detected by a voltage sensor (not shown) is also introduced to the protection relay 8 via the power cable 9, so that the protection relay 8 protects the drive motor 3.

That is, the protection relay 8 is actually connected to the main circuit of the drive motor 3 via the power switch MC as shown in FIG. 3, thereby tripping the main circuit of the drive motor 3 when protection is necessary. and configured to protect it.

FIG. 4 shows an example of the structure of the protection relay 8.

In other words, this protective relay 8 includes an overcurrent relay element 10 that trips the main circuit of the drive motor 3 in response to an increase in current due to a voltage drop in the power supply, and an overcurrent relay element 10 that trips the main circuit of the drive motor 3 in response to a change in the blowing pressure of the blower 2. The above-mentioned overcurrent relay element 10
The pressure change relay element 11 that promotes the tripping operation is prevented.

Here, the overcurrent relay element 10 is, for example, a bimetal type thermal relay element that moves a bimetal movable piece upward in the figure to trip the main circuit of the drive motor 3 due to a temperature rise caused by an increase in current due to a voltage drop in the power supply. A relay is used, and the pressure change relay element 11 is, for example, a plunger that is displaced upward in the drawing in response to changes in the blowing pressure of the blower 2 to increase the movement change of the bimetal movable piece, that is, to promote tripping operation. ing.

In other words, this protective relay 8 combines an overcurrent relay element 10 and a pressure change relay element 11, and as shown in FIG. It is configured to also provide current protection.

Now, in the flow rate Q1 pressure H characteristics of the blower 2 shown in FIG. 6, the resistance load curve changes from R□ to R2 depending on the drying state of the object to be loaded or the object itself.

That is, the cooling flow rate of the drive motor 3 changes and the load current also changes, and these conditions are also influenced by the increase in current when the voltage of the power supply drops.

Therefore, as described above, the protection relay 8 is composed of the overcurrent relay element 10 and the pressure change element 11, which detect the change in the blowing pressure of the blower 2 and the voltage drop of the power supply, and respond accordingly.
By providing this in the main circuit of the drive motor 3, it is possible not only to reliably prevent burnout of the drive motor 3 due to overheating, but also to ensure the appropriateness of the load on the drying platform 6.
It is possible to automatically stop the vehicle due to a change in the load during operation, take precautions against a voltage drop in the power supply, and rationally use and protect the drive motor 3 for this purpose.

[Effect of idea]

As explained above, according to the present invention, in a blower with a built-in motor, which is driven by a drive motor supplied with power from a power source and cools the drive motor by its own air blowing, an overcurrent relay element that trips the main circuit of the drive motor in response to an increase in current due to a voltage drop; and an overcurrent relay element that displaces in response to changes in the blowing pressure of the blower to facilitate the tripping operation of the overcurrent relay element. The blower is equipped with a protective relay consisting of a pressure change relay element, so the blower is highly reliable and can reliably protect the motor at its operating limits against voltage drops to the motor and static pressure of the blower. Equipment can be provided.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing an embodiment of the present invention, Fig. 2 is a configuration diagram showing a protection relay in the same embodiment, Fig. 3 is a circuit diagram showing an actual connection configuration of the protection relay, and Fig. 4 Figure 5 shows the usage limit curve for protecting the drive motor of the blower, and Figure 6 shows the characteristics and load characteristics of the blower. . 1...Dryer, 2...Blower, 3...
...Drive motor, 4...Burner, 5...
...Furnace, 6...Drying platform, 7...
・Pressure detection cable, 8...Protection relay, 9.
...Power cable, 10...Overcurrent relay element, 11...Pressure change element.

Claims (1)

[Scope of utility model registration request] Driven by a drive motor supplied with power from a power source,
and an overcurrent relay element that trips a main circuit of the drive motor in response to an increase in current due to a voltage drop in the power supply, in a blower with a built-in motor that cools the drive motor by its own air blowing; A blower device comprising a protection relay comprising a pressure change relay element that is displaced in response to a change in the air blowing pressure of the blower to promote tripping of the overcurrent relay element.