跳至主要内容

The Aging & Life Assessment of Oil-immersed Power Transformer

The aging mechanism of insulating material and factors influencing aging of oil-immersed power transformer are summarized,characteristics of aging mechanism in the courses of thermal aging,electrical aging,mechanical stress and multi- stress aging are concluded.

What are the Aging reasons of Oil-immersed Power Transformer?

In the long-term operation of transformer, insulation aging will be caused by electric field, moisture, temperature and mechanical force.
Oil-immersed transformer tank manufacturing
Oil-immersed transformer tank manufacturing

Oil-immersed Power Transformer Life assessment

Polymerization degree (DP) of transformer insulation material is the most accurate, reliable and effective criterion for insulation aging degree. According to the average degree of polymerization of insulated cardboard to judge the aging degree of transformer, we adopt the following criteria.
Evaluation Criteria of Average Polymerization Degree of Insulating Paper
Classified   life-level    hazard level
Average DP   < 450      < 250
1) The index of life level is that the maximum residual tensile strength of insulating paper can be withstood reaches 60% of the initial value when the external short circuit occurs; the dangerous level is that the maximum residual tensile strength reaches 15% of the initial value.
2) The criteria of DP failure probability of Japanese insulating paper fibers are as follows: 1) DP > 450, failure probability = 0; 2) 450 > DP > 250, failure probability =( 450 – DP) / 200; 3) 250 > DP, failure probability = 1.
 3) The residual life of transformer is estimated by average DP, i.e. nL/n0= (1 – r) L, where n0 is the starting value of average DP; nL is the average DP after L; L is the number of years; R is the average decline rate of DP.

Transformer Tank Cooling Wall Production line:

Automatic Corrugated Fins Wall Manufacturing Line



CORRUGATED FIN FOLDING AND WELDING MACHINES

Corrugated Fins Wall Forming Machine



corrugated fins wall making machine

Full-auto PLC Corrugated Fins Seam Welding Machine



corrugated fins wall seam welding machine

Hydraulic Decoiler



steel roll feeding machine

Corrugated Fins Wall Leak Testing Machine



corrugated fins wall leakage testing machine

Want to know more?(Marketing Title)

Phone: 008615195010186
Email: cnkylt@aliyun.com

评论

发表评论

此博客中的热门博文

CNC MACHINE BE CLASSIFIED BY SERVO CONTROL MODE

Servo control mode to classify CNC machine tool. (1) open loop control CNC machine tool The feed servo drive of this kind of machine tool is open-loop, that is, there is no detection feedback device. Generally, its driving motor is a stepping motor. The main feature of stepping motor is that every time the control circuit changes the command pulse signal, the motor will rotate a step angle, and the motor itself has self-locking ability. The drive circuit is controlled by the pulse distributor, which controls the coordinate displacement by changing the number of pulses, the displacement speed by changing the frequency of pulses, and the direction of displacement by changing the distribution sequence of pulses. Therefore, this control mode is characterized by convenient control, simple structure and low price. The command signal flow from the CNC system is unidirectional, so there is no stability problem of the control system, but because the error of the mechanical transmission...
发表评论
阅读全文

Tapping failure reasons analysis

After the first metal part be tapped, we always to check it: if pass the thread gauge inspection? The inspection result is OK, we can do mass production. If it fails, We should consider which reasons cause tapping faiulre. KYLT provide Metal Machining services for:  WEDM, EDM, DRILL, TAPPING ,  CNC LATHING ,  CNC MILLING ,  ALUMINUM / MAGNESIUM / PLASTIC RAPID PROTOTYPES MAKING . 1PCS ORDER IS ALLOWED. Aluminum CNC machined workpiece Normally, the following reasons may cause screw thread faiulre: 1) UNQUALIFIED TAP Tap is wear or bad 2) QUALIFIED DRILLING HOLE (BEFORE TAPPING) If the hole is too small, because of friction, will increase the difficulty of tapping, while tapping faster wear, and vice versa, the hole is too big, it can easily tap into, but the quality of teeth is very poor, because the diameter of teeth will become larger, relative to the screw nut bonding force is insufficient, easy to slide teeth. In M3 *0.5, the correct hole (general...
发表评论
阅读全文

SELECTION PRINCIPLE OF CUTTING PARAMETERS FOR SCREW THREAD TURNING

Because the pitch (or lead) of the thread is specified by the drawing, the key to choose the cutting parameters when  turning  the screw thread is to determine the spindle speed n and the cutting depth AP. 1) SELECTION OF SPINDLE SPEED TO DO SCREW THREAD TURNING According to the mechanism that the spindle turns 1 and the cutter feeds 1 lead when turning the thread, the feed speed of the CNC lathe is determined by the selected spindle speed. The thread lead (which is the pitch when the thread is single head thread) instructed in the thread processing program section is equivalent to the feed speed VF VF = n f (1) expressed by the feed rate f (mm / R) From Formula 1, it can be seen that the feed speed VF is proportional to the feed amount F. if the spindle speed of the machine tool is selected too high, the converted feed speed will greatly exceed the rated feed speed of the machine tool. Therefore, when selecting the rotation speed of the main shaft for turning the threa...
发表评论
阅读全文