هذا اموضوع عن هندسة الجهد العالى

إنضم
23 يونيو 2009
المشاركات
59
مجموع الإعجابات
1
النقاط
0
السلام عليكم ورحمة الله وبركاته
هذه بعض التجارب التى تحدث بمعمل الجهد العالى وللأمانة هى منقولة من موقع اخر
High Voltage Components
First of all, the HV experimenter who wants to work in the range of tens or hundreds of kilovolts is confronted with the problem that suitable parts are not readily available in electronic stores. In general, they are manufactured by specialized companies, and they are very expensive, sometimes unaffordable, when purchased new. With some luck, used parts or NOS (new old stock) parts can be acquired through junk yards, recycling facilities, surplus stores, or Ebay. Prices vary over a wide range. The following is a display of some of the various HV components I was able to procure in recent years. My experimental HV power supplies described later are based on some of these components

The first photo shows a 100:1 potential transformer (PT). Such transformers are used to monitor 11 kV AC power lines by measuring the much lower secondary voltage with a conventional voltmeter. The transformer is extremely robust and can handle considerable voltage and current overload temporarily. When using the transformer in reversed mode, it is a very nice source for high voltage (AC). Driving the secondary (now primary) coil with 150 V RMS @ 50 Hz yields a peak voltage (PV) of approx. 21 kV at the high voltage terminal (the big screw on top of the transformer). This is about the maximum voltage the transformer can handle at 50 Hz. At this point, core saturation becomes a problem. The wave form of the output voltage gets distorted, the humming noise of the core (magnetostriction) changes due to the increasing amplitude of harmonics, and, more important, the primary current increases rapidly. Since we have a line voltage of 230 V @ 50 Hz in Europe, a step-down transformer is required. Feeding the PT with 115 V AC (resulting in 16 kV PV) for several hours does not cause overheating. Potential transformers are very expensive and hard to get. I was lucky to find three of the same type at a local junk yard (dirt-cheap). They were brand-new, and each one of them was still in a sealed box! This gives me the chance to build a three-phase HV power supply some day. PTs are much more powerful than neon sign transformers or oil burner ignition transformers often used by HV experimenters.

clip_image001.jpg



100:1 Potential Transformer (Manufacturer: ABB)


This is a 200:1 potential transformer, the biggest and heaviest (31 kg) piece of my small collection (I have two of them now). It is designed to monitor 20 kV power lines. The HV coil can be driven to more than 30 kV RMS (>40 kV peak voltage) without problems.




200:1 Potential Transformer (Manufacturer: VEB Transformatoren- und Röntgenwerk Walter Matern, former GDR)

clip_image003.jpg


Here is another 100:1 potential transformer. In contrast to the above transformers, this one has a floating high-voltage coil. Therefore, it can be used in combination with a full-wave rectifier bridge.

clip_image001.jpg


100:1 Potential Transformer (Manufacturer: Ritz, Germany)



After some research, I found a supplier of new, commercial grade HV capacitors. I use two types, 50 nF / 20 kV DC and 22 nF / 40 kV DC (see below). These are well suited to the peak voltage of my smaller transformers (approx. 20 kV) since in a Cockroft-Walton circuit, the first capacitor is charged to the peak voltage of the transformer and all following capacitors to twice the peak voltage.




 

مواضيع مماثلة

saad_srs

عضو جديد
إنضم
9 أكتوبر 2010
المشاركات
1,125
مجموع الإعجابات
140
النقاط
0
مشكوررررررررررررررررررر
جعله الله في ميزان حسناتك
 
أعلى