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Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
I can run a Magnifier indoors with everything refered to mains earth except the secondary, both wires go outside to EARTH and Resonator base. Seems ok so far, but then I don't use high power !
Registered Member #135
Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735
I'm running about 720-750W depending on total draw. I'm using a counterpoise of roughly 2' square lying on the concrete, EMI mains filter, and then to variac. Sometimes when I don't wear my anti-stat band I can get some nasty shocks to case grounds because my body acts like an antenna (remember this). Anyway, my scope is fine in the garage about 20' from the coil, it is grounded. My generator though, which I was using to control a SSR for the rotary gap had some issues. At low input to the coil I was getting some back-feeding which changed the output frequency and duty so I discontinued doing that immediately and rigged my old flyback driver to pulse the SSR.
So what's the big deal, well, anti-stat bands do work to eliminate nasty 1KV+ surprises, but what I want to say is that when I drive my flybacks (HF pratically a Tesla Coil or DRSSTC) I get much worse shocks when I'm fooling around, and its only 36W!!!!!!! I am pointing out that if you're using a solid state device spitting out HF HV, FROM WHAT I OBSERVE, it interferes with equipment more. I have had some surprise shocks from cases at full 720-750W but they weren't nearly as painful or large compared to my little flyback driver.
Registered Member #127
Joined: Fri Feb 10 2006, 03:36PM
Location: Cincinnati, OH - USA
Posts: 44
On the mention of an EMI filter for the mains line, does anybody have a suggestion on brands, suppliers, or specifications? The only thing I can figure I probably want is 15A since I plan on eventually adding a second NST. Any good resources to compare these things?
I didn't get to test out my new ground setup last night. By the time I got everything gathered it was getting too late (I am sure my neighbors love me). Also I discovered I either have a knack for finding large rocks 2.5' underground or my entire apartment complex is built on a giant slab of concrete. Still looking for a place to drive a grounding rod.
Registered Member #135
Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735
Oh...forgot to mention about the EMI filters. I was reading a webpage where the EMI filter was connected backwards. The guy thought the load was the source. Anyway, since he connected his counterpoise ground to the ground prong on the case it send horrendous RF currents into the network, destroying it. So remember line means line and load means transformer side.
What I have done, since I only had one ground pin, is solder a ground pin to the load side and connect that to the case of the transformer. When I get everything worked out and finialized, that ground pin will connect to the case of the transformer, strike rail and midpoint of the HV filter (if I see necessary, at the moment its not). It will not however, connect to the counterpoise. I might connect an ammeter between the two to see what I get.
Registered Member #127
Joined: Fri Feb 10 2006, 03:36PM
Location: Cincinnati, OH - USA
Posts: 44
Hazmatt_(The Underdog) wrote ...
Oh...forgot to mention about the EMI filters. I was reading a webpage where the EMI filter was connected backwards. The guy thought the load was the source.
I read the same page. Luckily I've been around ordinary electronics enough to have most of the basic priciples down. This is my first foray into the HV world and one thing I gathered from all my reading online is: forget most of the rules. So far this is holding true. Hopefully tonight will go better than last and I can put some of these suggestions into practice (and annoy my neighbors at the same time).
Oh, and I just ordered a 20A EMI filter from Mouser. Thanks again everybody for all the input.
Registered Member #127
Joined: Fri Feb 10 2006, 03:36PM
Location: Cincinnati, OH - USA
Posts: 44
ForceLabs wrote ...
I got 2 240V 20A EMI filters from Corcom for free......
Did you get them in a way that could be duplicated by the rest of us? Or were they a find?
I just got finished packing up my coil for tonight. I still have an Internet connection so it looks like something I changed worked. Though I am running a Realtek 8139 based card now instead of an Intel Pro100S. It may be less sensitive. What I did tonight:
Found a spot to drive a 2.5' copper ground stake.
Changed secondary ground from rigged connectors to wire pinched between washers on a mounted brass stud.
Changed secondary ground cable from 12ga stranded THHN to 6ga stranded THHN (using ring connector to stud mentioned above). Length is still 10'.
Added earth ground connection to my NST.
Wrapped NST mains cord twice through ferrite toroid (may be trivial, but I figured it couldn't hurt).
So far I haven't found anything that died and I actually got bigger breakouts. Thanks again to everybody for all the input.
Registered Member #158
Joined: Sun Feb 12 2006, 09:53PM
Location: Central Ohio
Posts: 282
Hazmatt_(The Underdog) wrote ...
Oh...forgot to mention about the EMI filters. I was reading a webpage where the EMI filter was connected backwards. The guy thought the load was the source. Anyway, since he connected his counterpoise ground to the ground prong on the case it send horrendous RF currents into the network, destroying it. So remember line means line and load means transformer side.
I wondered about this since I purchased a large emi filter from mendelsons, it was like 240v/30amp or something... only like $5. But those filters are designed to keep noisey line current from comming into a sensitive device arent they? In which case our goal would be to keep the noise inside our device and prevent from backfeeding into the mains... so shouldnt it be hooked up in reverse?
FWIW the video clips of my larger coil 'quantum 2' on my website are on a 3rd floor apartment gorunded to mains. About 4' sparks. I used the main grnd often enough that I broke off the round ground prong from and extension cord and soldered it to my ground wire so it was easy to slip in and out when I setup my coils. I did unplug everything electronic from all outlest though... hope I didnt fry anything from the neighbors
Registered Member #135
Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735
I was playing with my coil tonight, with the filter, and my dad was freaking out a little as he saw the triac controlled light dimmer act crazy when I was running. I guess I can't keep it a secret after all.
I like the ferrite idea, even though there are already ferrites in the line filter.
You really need to connect the line filter properly because its designed to clamp surges on the load side, not the line side.
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Earth Ground for Apartment Dwellers
Luckily I've been around ordinary electronics enough to have most of the basic priciples down. This is my first foray into the HV world and one thing I gathered from all my reading online is: forget most of the rules. 
So far this is holding true. Hopefully tonight will go better than last and I can put some of these suggestions into practice (and annoy my neighbors at the same time).
