1. Winding electricity heating method
Heating methods are more, such as hot oil circulation, hot air circulation, eddy current heating, kerosene vapor, etc., can be selected according to local conditions, with its director. However, when these methods are used to process the voltage transformer, it appears that the EQUIPMENT is bulky and complicated, the power capacity is large, and the power consumption is more and more. The site preparation work requires a long time and the construction is difficult.
The voltage transformer short-circuit their own high-voltage winding, low-voltage winding lights (12V) through the current heating. JCC-110-type voltage transformer winding arrangement: the outer auxiliary winding (aD, xD), the innermost high voltage winding, the middle is the low voltage winding (a, x), and the low voltage winding is in the lower most susceptible to moisture s position. Therefore, heating from the low-voltage winding is better than heating from the auxiliary winding so that the internal moisture can evaporate better.
The heating current starts at 30A, and then the temperature is converted as the low-voltage winding resistance changes the current size at any time. When the winding temperature exceeds 80 â„ƒ, the winding temperature to be controlled at 80 - 90 â„ƒ, the temperature level can be determined by the degree of moisture. Special attention should be given, do not heat up too fast, the current value of the increase or decrease is small, or the temperature will increase rapidly. It is best to test the temperature every 15 minutes.
2. Vacuum degassing heat treatment
110kV voltage transformer vacuum degassing heat treatment, the drying time is shorter. This drying process than in the oven treatment has the following advantages:
1) The processing equipment is simple and requires only 1 vacuum pump (1.1kW), 1 voltage regulator (0.5kV) and 1 line transformer (300V Â· A, 12 / 220V).
2) On-site processing, hoisting and transportation can save costs. As not lifting, but also to avoid the temporary electrical equipment near the blackout.
3) The winding itself energized and dry, windings heated evenly, good drying effect.
4) This drying method, suitable for all types of voltage transformers and current transformer drying.
3. Judgment of dry conditions
The voltage transformer drying process and the results of the judge, mainly to measure the dielectric loss angle and insulation resistance. Before the test should be wiring small casing and the wiring board clean, so as not to affect the measurement results.
A hub is the center part of a Bicycle Wheel. It consists of an axle, bearings and a hub shell. The hub shell typically has two machined metal flanges to which spokes can be attached. Hub shells can be one-piece with press-in cartridge or free bearings or, in the case of older designs, the flanges may be affixed to a separate hub shell.
Hub shell and flanges:
The hub shell is the part of the hub to which the spokes (or disc structure) attach. The hub shell of a spoked wheel generally has two flanges extending radially outward from the axle. Each flange has holes or slots to which spokes are affixed. Some wheels (like the Full Speed Ahead RD-800) have an additional flange in the center of the hub. Others (like the some from Bontrager and Zipp) do not have a noticeable flange. The spokes still attach to the edge of the hub but not through visible holes. Other wheels (like those from Velomax/Easton) have a threaded hub shell that the spokes thread into.
On traditionally-spoked wheels, flange spacing affects the lateral stiffness of the wheel, with wider being stiffer, and flange diameter effects the torsional stiffness of the wheel and the number of spoke holes that the hub can accept, with larger diameter being stiffer and accepting more holes. Asymmetrical flange diameters, tried to mitigate the adverse effects of asymmetrical spacing and dish necessary on rear wheels with many sprockets, have also been with modest benefits.
Bicycle Hub,Alloy Track Hub,Sealed Bearing Hub,Disc Brake Hub
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