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Registered Member #60240
Joined: Mon May 16 2016, 07:01PM
Location:
Posts: 304
The picture shows an electrostatic voltmeter with light pointer for a maximum of 10 kV.
My questions to all:
Please, who else has an electrostatic voltmeter in his instrument collection? Do you have some experience in dealing with voltage measurement by electrometers? Have you perhaps measured the self-capacitance and the internal resistance of your device?
Registered Member #135
Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735
I have one, a 30KV unit, but its buried and I have not measured it. The internal resistance should be tens of mega ohms, if not a hundred mega ohms.
Unfortunately, I broke my 30KVDC spellman high voltage power supply, so I don't really have anything to test with. If you get a piece of tube test equipment.. its probably better not to try to clean it and break it in the process.. ;p
Registered Member #61569
Joined: Sat Apr 15 2017, 05:12PM
Location: Germany
Posts: 28
We have several of these but they are not in use any more. If i remember right, then one was for 30kV (exactly like this one ), one for 100 kV and one for up to 400kV. The last one is almost 2.5m high and have electrodes with 1m in diameter. If you are interested i can make some pictures of these. The resistance is very high. At least it is in the range of Tera Ohms.
Registered Member #60240
Joined: Mon May 16 2016, 07:01PM
Location:
Posts: 304
Hi Flachzange
Both electrometers (Starke & Schröder) are wonderful instruments. Please, may I ask you
1. What are the experimental errors for each measurement (precision as well as accuracy) 2. What is the procedure to calibrate these instruments 3. What standards do you have available for these high voltages?
Registered Member #61569
Joined: Sat Apr 15 2017, 05:12PM
Location: Germany
Posts: 28
Hi,
to 1.) i can not say anything, since these were not used within the last 20 years or even longer. In the box of the first one might be the instructions were the uncertainty is listed. I will look it up and report if i find something. 2.) For the calibration: I would compare these to a reference divider and then check them over the entire voltage range. 3.) Our reference divider for DC is made for 100 kV with an extended (k=2) uncertainty of 2ppm (0,0002%). For up to 300 kV we have to dividers with 10ppm. And within the last two years i have build four dividers each with 400 kV (20 ppm). They can also be combined (stacked on top of each other) to measure voltages up to 1.6 MV.
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