JP3694361B2 - Maintenance electric motor drying furnace and drying method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drying furnace and a drying method for a maintenance electric motor.
[0002]
[Prior art]
An electric motor (mill motor) that drives a steel rolling mill or the like becomes large in weight by 10 t or more (output by 1000 KW or more). In such an electric motor, since the deterioration of the insulator progresses with the lapse of time of operation of the rolling mill, the timing of the insulation improvement countermeasure construction is determined by diagnosis, and the insulation improvement countermeasure construction is performed based on this determination. In this construction, first, the rotor of the electric motor is removed and divided into two parts, each of which is sprayed with steam to clean and remove oil stains, dust, brush powder, etc. on the insulator and then dry. Thereafter, as an insulation treatment, for example, varnish is sprayed and applied to the insulator, and then dried to complete the insulation improvement work.
[0003]
[Problems to be solved by the invention]
For such drying after cleaning, the electric motor after cleaning is generally inserted into a simple assembly furnace at a maintenance site, hot air is blown and dried under normal pressure, and varies slightly depending on the size of the electric motor. , Need more than 48 hours. Similarly, in the drying after spraying the varnish to the insulating material as the insulating treatment, it is dried by heating under normal pressure as described above. For this reason, drying takes a long time, maintenance work takes a long time, and the rolling mill downtime also lasts for a long time, resulting in a decrease in the productivity of steel rolling. In addition, if the drying time is prolonged, it will be exposed to heating for a long time, the insulation of the motor that has been maintained will be thermally deteriorated, the degree of insulation recovery will be reduced, the life extension effect will not be improved so much, and the maintenance interval of the motor will be increased. Short cycle. Therefore, there are problems such as lowering the operating rate of the rolling mill and increasing maintenance costs.
The present invention has been made in order to advantageously solve such problems, and a drying furnace that can quickly solve the problems as described above by drying quickly when the motor is dried after washing and insulation treatment. And an object of the present invention is to provide a drying method.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the maintenance electric motor drying furnace of the present invention has a moving rail of a maintenance electric motor carriage in the vacuum drying furnace, and a lower part and a side of the maintenance electric motor carriage loading position of the vacuum drying furnace. with arranging a heater section, upwardly disposed a blower tube in air at room temperature to just below the maintenance motor conveyance carriage loading position lower heater, to heat the developed electric motor as hot air of the vacuum evaporation temperature by a heater, hot air in the furnace It is characterized by having a structure in which the flow is convected and diffused from the upper exhaust valve . The maintenance motor drying method of the present invention is characterized in that the motor that has been cleaned or insulated is heated to the vacuum evaporation temperature inside the drying furnace according to claim 1 and then evaporated and dried in a vacuum state. It is.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
As the above-mentioned heater, for example, a heater panel is heated by electricity, steam or the like, and heated by contacting with an electric motor on a carriage as hot air by contact with air blowing (air etc.) from a blower tube. This heating temperature is for heating to the vacuum evaporation temperature. For example, when the surface temperature of the electric motor reaches 40 to 60 ° C., the inside of the furnace is evacuated to about 5 tr. Moisture can be quickly and reliably evaporated and dried, and if the degree of vacuum is further reduced, the surface temperature of the electric motor can be evaporated and dried. In addition, for example, when the varnish applied to the insulating material is dried after the cleaning, the air can be quickly dried by drying in the same manner. When the electric motor temperature reaches about 60 ° C. after the drying, the air is blown by the heater. Cooling can be performed more quickly by stopping the heating, switching to normal temperature air blowing, and air cooling.
In such blast heating into the furnace, the temperature difference between the upper and lower positions of the electric motor can be kept within 5 ° C by convection of the hot air flow in the furnace, and the quality of the electric insulator is prevented from being deteriorated. It is possible to dry while reliably preventing the decrease.
[0006]
As described above, when drying after the insulation treatment, a part of the varnish is melted and dropped by heating, so it is preferable to provide a molten dropping liquid receiving pan directly under the carriage to prevent scattering into the furnace. By providing it in a staggered manner in the inner width direction, it is possible to receive the dripping liquid reliably without hindering convection ventilation.
[0007]
【Example】
Example 1
Next, the Example of this invention drying furnace is given.
1 and 2, a rail 2 communicating from the outside is laid in a vacuum drying furnace 1, and a maintenance electric motor carriage 4 loaded with a motor 3 after cleaning or insulation treatment to be dried on the rail 2 is externally mounted. Then, room temperature air is blown into the furnace 1 from the blower pipe 5 disposed at the lower part of the carry-in position of the maintenance motor transport carriage 4, and is moved to the lower part and the side part of the maintenance motor transport carriage 4. Heating is performed by the heaters 6, 6 a, 6 b arranged to contact and heat the electric motor 3 on the maintenance electric motor transport carriage 4 as hot air, and convection in the furnace 1 is diffused from the upper exhaust valve 7. In this way, the electric motor 3 is heated to the vacuum evaporation temperature, and then the ejector (not shown) is operated to reduce the boiling point by evacuating the furnace 1 to remove the water after washing or the varnish solvent after the insulation treatment. It is removed by evaporation. In the figure, reference numeral 8 denotes a molten dropping liquid receiving pan.
[0008]
Next, the lid hanging mechanism before and after the vacuum drying furnace will be described.
In FIG. 3, a lid 10 is disposed on a movable carriage (electric carriage) 12 via a holding frame 11, and the movable carriage 12 is coupled to a rail carriage 13 via a coupling mechanism. This coupling mechanism is composed of a spring 14 having a buffer absorption function and a spline 15 having an expansion / contraction function. When the lid 10 closes the maintenance motor transport carriage entrance before and after the vacuum drying furnace 1, the movable carriage 12 is moved by the positioning stopper 16. By moving to the position where the rail carriage 13 stops, the lid 10 of the vacuum drying furnace 1 is reached and the lid is hung. In addition, when opening the lid of the maintenance motor transport carriage entrance before and after the vacuum drying furnace 1 in order to load and unload the maintenance motor transport carriage, the spline 15 contracts by moving the movable carriage 12 to the position of the positioning stopper 16. Then, the lid 10 is moved from the position of the vacuum drying furnace 1. The maintenance electric motor carriage is moved into and out of the vacuum drying furnace 1 by removing the positioning stopper 16 and moving the movable carriage 12 so that the rail 2a of the rail carriage 13 is connected to the rail laid in the vacuum drying furnace 1. Move the transport cart. In this way, in the lid 10 of the vacuum drying furnace 1 and the like, as described above, the connection between the movable carriage 12 and the rail carriage 13 is performed in the direction perpendicular to the vacuum drying furnace 1 by the connecting mechanism having the expansion / contraction function (spline 15). The lid can be opened and closed in a narrow space, and the layout at the work site can be made compact, which is extremely effective.
[0009]
Example 2
Next, examples of the drying method of the present invention will be given together with comparative examples.
An electric motor weight of 30 t (rotor removal) is placed in a vacuum drying furnace (length 5 m, diameter 5 m), then room temperature air is blown upward from the furnace bottom by 15 Nm ³ / min, and hot air (110 ° C.) is heated by a heater in the furnace. ), And after 2.5 hours, when the motor surface temperature reached 58 ° C., the inside of the furnace was kept at a vacuum of 5 tr and after 1.0 hour, drying was stopped. At this time, the surface temperature difference between the upper and lower positions of the motor could be heated and dried almost uniformly at 3 ° C.
[0010]
After the insulation treatment by spraying and applying the liquid varnish generally used for the insulator of the electric motor cooled and dried after washing as described above, it is charged into the vacuum drying furnace as described above and blown at 15 Nm ³ / min. After 4.0 hours of contact with the motor in the form of hot air (110 ° C) with the internal heater and convection, when the motor surface temperature reaches 100 ° C, the furnace is maintained at a vacuum of 5 tr Stopped drying. At this time, the surface temperature difference between the upper and lower positions of the motor could be heated and dried almost uniformly at 3 ° C. Further, when the insulation resistance was measured, 1000 MΩ or more and no thermal deterioration of the motor insulator was observed.
[0011]
Comparative Example An electric motor similar to that in Example 2 was charged into an atmospheric drying furnace, the inside of the furnace was heated to 110 ° C. (non-flow heating), and after 8.0 hours, the electric motor surface temperature reached 90 ° C. After the time, it was heated at the same temperature to finish drying. At this time, the temperature difference between the upper and lower positions of the motor reached 20 ° C. After insulation treatment by spraying and applying varnish to the insulator of the motor cooled and dried in this way, the furnace was charged into a drying furnace and heated to 110 ° C. under normal pressure, and after 36 hours had elapsed, drying was stopped. . At this time, the surface temperature difference between the upper and lower positions of the motor reached 20 ° C. Further, when the insulation resistance was measured, the insulation recovery was as low as 200 MΩ, and uneven varnish curing was also observed.
[0012]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the washing | cleaning of an electric motor or the drying after an insulation process can be performed rapidly, the stop period of a rolling mill etc. can be shortened, an operation rate can be improved, and productivity can be improved. In addition, since the drying time can be remarkably shortened, it is possible to prevent thermal deterioration of the motor insulator, and to obtain excellent effects such as maintenance of the motor while avoiding a decrease in function of the motor.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of the present invention.
FIG. 2 is a side view of an essential part showing an embodiment of the present invention.
FIG. 3 is a side view showing a lid opening / closing mechanism of a drying furnace.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vacuum drying furnace 2 Maintenance motor conveyance trolley carriage rail 4 Maintenance motor conveyance trolley 5 Blower 6 Heater 6a Heater 6b Heater 8 Melting dripping liquid receiving pan

Claims (2)

A moving rail of the maintenance motor transport carriage is laid in the vacuum drying furnace, heaters are arranged at the lower part and side of the maintenance motor transport carriage carrying position of the vacuum drying furnace, and directly below the lower heater of the maintenance motor transport carriage delivery position. It features a structure in which a normal temperature air blast pipe is arranged upwards, the maintenance motor is heated as hot air at a vacuum evaporation temperature by a heater , and the hot air flow is convected in the furnace and then diffused from the upper exhaust valve. Maintenance electric motor drying furnace.   A method for drying a maintenance motor, comprising: heating the cleaned or insulated motor to a vacuum evaporation temperature inside the drying furnace according to claim 1;

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