[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: [TCML] NST Measurements
Hi Gary, Bart, All,
?
Back in Oct '07 I measured the Vin/Vout ratio forward and backward on a 15/30 Transco NST using an old Triplett 630-Aanalog meter, which has a 6KVAC scale. The forward ratio was 124:1 at 48.4 Vin implying 14880 Vout at 120 Vin, but the reverse ratio was only 37:1 with 120 Vin on the secondary. These results are very inconsistant.?I will have to rerun it when I get a chance, but it seems to indicate that the reverse method doesn't work well for an NST
?
Matt D.
-----Original Message-----
From: Lau, Gary <Gary.Lau@xxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Sun, 18 Jan 2009 6:54 pm
Subject: RE: [TCML] NST Measurements
Hi Bart, As often as I have dispensed the same advice to measure and feed the mains voltage into the NST secondary and measure the primary to determine the sec/pri ratio, I don't recall ever having actually done that to mine. So, I just pulled out a 15/30 and a 15/60 NST. The 15/30 measured a ratio of 153X, so assuming a 120V primary, predicts a 18.3kV secondary. The 15/60 measured a ratio of 145X, so assuming a 120V primary, predicts a 17.4kV secondary. The meter that I used is a simple Fluke DMM, not RMS. But given that the NST is going backwards, I wouldn't think that it's getting near saturation and the associated waveform weirdness. Unfortunately I don't own a HV probe that I would trust to measure it in the normal operating sense. Have you done this and gotten closer to the faceplate voltage rating? Regards, Gary Lau MA, USA > -----Original Message----- > From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On > Behalf Of bartb > Sent: Sunday, January 18, 2009 5:37 PM > To: Tesla Coil Mailing List > Subject: Re: [TCML] NST Measurements > > Hi Jeremy, > > How you perform a measurement depends largely on the equipment you have > on hand and what it is you want to identify. So my first question is > what meters do you have hand to make measurements? Obviously, a HVac > probe would be ideal, but not absolutely necessary to simply identify > rough specs. If you have say only a digital rms meter handy, hook up > 120Vac to the output side and measure voltage on the primary. This will > do fine for identifying your turns ratio (Vout/Vin). Then you can just > figure wall plug AC volts x turns ratio for the output. Current more > complicated. > > If you want to look at "more" and get to know the transformer for what > it really is, two meters are helpful. One to read current and the other > to read voltage along with a HV probe. I'm not a big fan of reverse > wiring t
he transformer to gain transformer characteristics other than > the basic turns ratio. When normal current is flowing, it will be > different from the reverse wired situation because the secondary voltage > applied is never the output volts (but some far lower voltage). If you > could, a hv probe would be needed. But at that point, you may as well > feed low voltage high current to the primary for ease of measurements. > > So again, what equipment do you have on hand? > > Bart > > Jeremy wrote: > > Ok, wait, so how exactly do you guys propose measuring NST outputs for > dummies? i have 9kV 30mA unit as well as a large unlabelled unit atm, and the > unlabelled one arcs at over half an inch so i'm guessing it's at least 15kV 60mA. I > need the measurement on the unlabelled unit. I was thinking of using a 10V input to > the NST, then further stepping down the output by 20x to be measured by a > voltmeter. Is this workable? (all components rated at 240V input) > > > > > _______________________________________________ > Tesla mailing list > Tesla@xxxxxxxxxxxxxx > http://www.pupman.com/mailman/listinfo/tesla _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla