Electronics > Projects, Designs, and Technical Stuff
Open HV Probe 40kV
<< < (19/26) > >>
joeqsmith:
DC 0.00mA @ 1kV.
AC @50Hz 1kV 0.00mA
AC @1kHz 1kV 0.24mA


You lost me.   The meter's switch is set to  A/mA and the leads are connected to the Volts input. 

If I assume that everything was setup correctly when you took the actual measurements,  with the 1KHz@1KV signal,  if you just removed the red wire from the probe body as shown and let it rest on the wooden stool, does the current drop?

I made some posts about testing some capacitors for leakage.  One problem I ran into was how much my test jig would leak (the colored boots).  Ended up floating them from the case with some Teflon.  With you working in the 40KV level, I assume you are going to have some head room.  Maybe double that?   You may find that the materials cause an error in your measurements. 
https://www.eevblog.com/forum/testgear/using-low-voltage-levels-to-test-hv-capacitors-leakage-current/25/
beanflying:
 :palm: oops brain fart due to being in a rush grabbed the meter off the bench and forgot to swap. Tomorrow job I will have some free time and do it properly  ::)
joeqsmith:
This makes more sense.  Look forward to the actual numbers.  At 1KV, I am expecting the 121GW not to detect any thing but you never know.
kony:
Someone notify the Darwin awards commission, they might get a special serial entry brought you by the open source community (TM).

No, NO, and FUCK NO to the material and manufacturing selection for the insulator of the probe. Having dealt with reliability of manufacturing processes of 20kV PSU assemblies in the past, I am very painfully aware of how deep the rabbit hole goes to even start thinking about passing the design for production after several iterations of debug and validation of BOTH the design and manufacturing process. And you are attempting to get this out in a way such everyone can wing it with the leftovers just lying around? Gotta be shittin me! I am sorry, but I am not sorry for my languague, it is fully apropraite for the magnitude of the possible consequences this can have.

OP, do you have a single fucking clue about the E field distribution on the probe insulation, what air pocket inclusion or surface defect or grit contamination will do to it? Sensitivtity to moisture, long term stability of the plastic (selection of which you, BTW, have absolutely zero control over)? Corona resistance of the material should partial discharge occur - and what certanity is there it won't avelanche in the degradation? How about air gaps in the insulation to the center isntalled divider or elsewhere - do you at least understand what relative permitivity discontuinuity implies for local electric field magnitude?

Can you imagine the consequences of some poor bastard using such thing handheld on hard power supply?
beanflying:
Moving right along to some actual practical testing and data. Two Coffees this morning after a 4.30am Possum Roof visit  |O, wiped the seat and Neon Transformer over with IPA, probe as per yesterday uncleaned etc. 121GW plugged into the mA jack and had the correct range selected  :palm:

** I do have an issue with the Valhalla it seems on the 1kHz range it is clearly spraying noise as I was getting a current reading with the 121GW unconnected as per the pics below.

Feeling a little brave for the inner smoke on the 121GW I broke out the Neon Transformer to raise the stakes a little. 6+kV to Ground and 0.0000 mA so I am feeling happier about where I am heading. Forgot to take any snaps of in on the Fluke but Zero @ 1kV DC.

Photos remind me I must clean up and repaint the outside of the Neon.
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod