JPH056833A - Drying method of winding body - Google Patents

Abstract

PURPOSE:To provide the drying method, of a winding body, wherein the winding body can be dried in a short time and with good efficiency. CONSTITUTION:The inside of a drying furnace 1 is made vacuum by using a vacuum evacuation device 3; a winding 5 in a winding body 7 is connected to a DC power supply 11; the winding 5 is self-heated; the temperature of the winding body 7 is raised. Moisture which has been discharged from the winding body 7 due to the temperature rise is collected by using the vacuum evacuation device 3. The temperature of the winding body 7 is adjusted by using a temperature regulator 8 on the basis of the temperature which has been detected by using a thermocouple 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a winding body drying method for heating a winding body in a vacuum to dry it.

[0002]

2. Description of the Related Art Drying of a winding body used in an electric device, which is obtained by insulating a winding with an insulator, is conventionally performed by the method shown in FIG. The inside of the drying furnace 1 is made airtight, the vacuum exhaust device 3 is connected to the drying furnace 1 via the valve 2, and the heater 4 is provided inside the drying furnace 1.
The winding body 7 including the winding wire 5 and the insulator 6 is put into the drying furnace 1, the inside of the drying furnace 1 is evacuated by the vacuum exhaust device 3, and a current is passed through the heater 4 so that the inside of the drying furnace 1 is cooled. The temperature is raised to evaporate the water contained in the winding body 7 into the drying furnace 1, and the water is collected by the vacuum exhaust device 3.
In the figure, 8 is a temperature controller, 9 is a power controller, and 10 is a power controller.
Is the power supply.

[0003]

However, there are the following problems. Since the temperature rise inside the drying furnace depends on indirect heat transfer such as heat conduction and heat radiation, the heat exchange efficiency is improved despite various measures to increase the heat efficiency such as vapor phase drying. Low. Therefore, it takes time to raise the temperature in the furnace,
Moreover, much heating energy is wasted. On the other hand, a heater having a large heat capacity is required for drying in a short time.

Further, since the winding bodies of different sizes are dried in a single drying oven, a larger drying oven is required, and the smaller the volume of the winding body, the lower the thermal efficiency.

Therefore, an object of the present invention is to provide a method for drying a winding body which solves the above problems.

[0006]

The structure of the present invention for achieving the above object is to generate heat in the winding itself by passing a direct current through the winding itself constituting the winding body. It is characterized in that the winding body is dried by evaporating body water.

[0007]

[Operation] Since the winding itself generates heat to heat the winding of the winding body, the efficiency for heating the winding body is high,
The winding body can be dried in a short time.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. Since the present embodiment is an improvement of a part of the conventional winding body drying method, the same parts as those of the prior art will be designated by the same reference numerals, and the description thereof will be omitted.

FIG. 1 shows the construction of a drying oven or the like for carrying out the method for drying a winding body according to the present invention. In the figure, 11 is a DC power supply and 12 is a thermocouple. Next, a method of drying the winding body will be described. First, the winding body 7 is put into the drying furnace 1, the inside of the drying furnace 1 is evacuated by the vacuum exhaust device 3, the winding 5 is connected to the DC power source 11, and a current is passed through the winding 5. Make 5 self-heating. The DC power supply is used to heat the winding body 7 because the AC power supply may cause partial heating due to the influence of eddy current or the like. Since the winding body 7 exists in a vacuum, the electric power for heating the winding body 7 can be small.

2A and 2B show the temperature distribution of the winding body 7 when a DC current is passed through the winding 5 in a vacuum. Figure 2
(B) in (b) is the temperature distribution in the height direction along the line indicated by A in FIG. 2 (a), and similarly (b) is in the height direction along the line indicated by B. Is the temperature distribution of. As can be seen from this figure, the temperature distribution of the winding body 7 can be considered to be substantially uniform. Therefore, as shown in FIG. 1, the temperature of the winding body 7 is detected by the thermocouple 12 attached to the lead portion of the winding 5 having no insulating coating.

The temperature of the winding body 7 is adjusted by controlling the DC power supply 11 to be turned on and off by the temperature controller 8 based on the detected value of the thermocouple 12. As the temperature, for example, the temperature of the winding body 7 is set in the range of 95 ° C. to 105 ° C. as shown in FIG. The temperature relays 1, 2, 3 are 95 ° C, 105 ° C, 120
When the temperature is above ℃, it will turn on and the DC power supply 11 will have the temperature relay 1 turned off.
When it becomes FF, it becomes ON, and when the temperature relay 2 becomes ON, it becomes OFF. (C) in FIG. 3 is a graph in which time is plotted on the horizontal axis and temperature is plotted on the vertical axis. If each relay is normal, PQR and PQR will be continuous, but if the temperature relay 2 has failed. In case of temperature relay 2 at the point Q on the right side of the graph
Is not turned on, and then the temperature of the winding body 7 reaches 120 ° C., the temperature relay 3 is turned on, and the DC power supply 11
And, all the power supplies of the temperature controller 8 are turned off and the heating is stopped (the part surrounded by the broken line).

The moisture discharged from the winding body 7 due to the temperature rise of the winding 5 itself is recovered by the vacuum exhaust device 3.

[0013]

As can be seen from the above description, the method for drying a winding body according to the present invention has the following effects. Since a current is passed through the winding itself to generate heat, the winding body can be heated in a short time. Moreover, since unnecessary substances are not heated, they can be uniformly heated with a small amount of electric power, and there is no waste of heating energy. Since a heater is not required, it is possible to dry using a tank or the like that houses the winding body without a drying oven.
By controlling the temperature of the winding while detecting the temperature of the winding itself, proper drying is possible regardless of the size of the winding body.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a method for drying a winding body according to the present invention.

2A and 2B relate to a temperature distribution of a winding body, FIG. 2A is an explanatory view showing a temperature detection unit, and FIG. 2B is a graph showing the temperature distribution.

FIG. 3 is an explanatory diagram for temperature control according to the present invention.

FIG. 4 is an explanatory view showing a conventional winding body drying method.

[Explanation of symbols]

 1 ... Drying furnace 2 ... Vacuum exhaust device 5 ... Winding 6 ... Insulator 7 ... Winding body 11 ... DC power supply

Claims (1)

Claim: What is claimed is: 1. A method of drying a winding body in which a winding body made by insulating a winding with an insulator is heated in a vacuum to dry the winding body, and a direct current is passed through the winding. A method for drying a winding body, which comprises heating and winding the winding body with heat generated by itself.