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Alternator Testings -at- 481 hz



Original poster: "harvey norris by way of Terry Fritz <twftesla-at-qwest-dot-net>" <harvich-at-yahoo-dot-com>

HI ALL,
concerning the possibility of running a tesla coil
from the higher frequencies of an alternator, I have
aquired some test data of late. I am hesitant to
report such data if I did not consider it accurate, so
here two or three datas are made. these are made
running an alternator at between 476 and 481 hz,
established by running a 6 1/4 pulley from nameplate
1.5 hp 1725 rpm single phase motor to alternator
pulley of 2 1/4 diameter turning 7 pole face rotor,
(Delco Remy) As others (may have noted as potential
problems),the impedance of the ferromagnetic
components gets higher than book value derivations
will deliver. In the case sample here I have merely
delivered 30 volts, 17 volts, and the non energized
field rotation that delivers a analog voltage reading
of 2.1 volts AC stator phase input. Those voltages
were sent to the unballasted primary of a 10 KVA pole
pig, being considered as the candidate for a single
phase/alternator powered tesla primary. Most simple
indications would seem that an alternator can hardly
make the power requirements of making a decent tesla
coil high voltage discharge. Nevertheless ascertaining
the possibilities of higher than input 60 hz
frequencies as application remains a little researched
territory, possibly because of the formidable
impedance requirements that ensue.

To show the deviation from what the Wavetek LCR meter
reads, to what is actually experienced at 481 hz is a
fairly simple rendition of equations. The meter reads
26 mh,or .026 H for the pole pigs unloaded primary.
Following is extracted from notes;

Ran alternator to pole pig last night,from a single
phase only with nothing else loaded on other phases.
This seems to deliver the highest voltage from a
phase, when used in solitary application and showed
unexpected results. Impedance of its open loaded
primary,(measuring only 26 mH) at 481 hz seems
extraordinarily high. A 30 volt signal conducted only
106 ma! {Let us quickly calculate how far off the book
value gives here. By Z=V/I = 30/.106 =283 ohms.(Acting
Reactance) 
By X(L)=6.28*F*L= 6.28*481*.026 = 78.5 ohms (book
value reactance.) 
Thus the acting reactance was 3.6 times higher than
expected at 481 hz. At 300 volts input from the
secondary{{Of existing 3 Phase 15.7 KVA transformer
hooked to stator outputs, shown at Messagebord} only
1.06 amps conduction from the secondary should be
expected then as a reactive current to the pole pig
primary. Now to note the increased demand on that
(3)phases primary we might expect some 22.6(this being
the recorded step up ratio of the 15.7 KVA 3 phase
transformer) times the postulated 1.06 secondary
amperage gives a whopping 24 amps draw from a single
stator phase! I dont think the alternator can deliver
that amount of amperage, not for just a second before
meltdown! Before giving up however the possibility of
a power factor correction on that primary should help
matters. The primary of the transformer can easily
conduct that amount of amperage at 60 hz operation
because of its high KVA rating, but whether the same
thing can happen at 481 hertz is dubious.} 

(return to notes) I started out using the unfused 20
amp reading range of the meter, and switched to the
fused 400 ma and lower setting to get that(pole pig
amperage) reading. Then I got the dumb idea to put a 4
inch neon across the pole pigs outputs. I turned the
variac up from zero to where about 20 volts input, the
neon brightly flashed and the circuit was dead. This
caused me no end of consternation, because it (the
meter)is doing things it shouldnt do. What happened is
that because I was running the neon load with no
output ballasting to limit the output amperage, when
the neon conduction started, it appeared more of less
as a short to the pole pig secondary. This caused a
momentary high amperage demand at the primary where I
was measuring the amperage, and evidently must have
blown the meters fuse, going past the specified 400
ma. However I should have been able to simply go back
to using the unfused higher 20 amp setting on the
meter to reenable conduction. Doing this shows nothing
but open circuit, where even that phases voltage is
non existant if measured after the amperage line
interruption of meter. I cannot afford to keep frying
meters! My true rms Radio Shack meter,(which is a
piece of shit as far as making low amperage readings
anyways) got its voltage reading ability taken away
when I accidentary increased the secondary transformer
voltage past the meters 750 V meter warning limit. I
now use a needle meter (analog?) that can go to 1000
volts AC. Anyways I have to buy some fuses today and
see what the deal on that malfunctioning meter is.
Will write later as developements insue. HDN 

Radio SHACK,also replaced this meter today, after this
unique or stupid amperage measurement. Obviously My
stupid measurement pinged the meter with an
unnacceptably high amperage, but given the high
impedances involved it shouldnt have been a 20 amp
ping! The meter in question,model 22-805 (with PC
interface!) is rated for that. Unfortunately for old
timers like myself, I am used to overating the 400 ma
limit, and if the fuse blows, I can simply replace it,
OR i could just turn to the unfused higher amperage
level and just get an slightly more inaccurate smaller
scale measurement of the amperage. Imagine my
amazement in attempting to install a fuse, because
there is none! You have an accident so simple as that
and your RS amperage meter is wiped out with no
recourse for repair, and will read infinite
resistance, immediately disabling any kind of amperage
measurement on any scale. Its funny how the meter will
tell you your invention doesnt work when you monitor
its amperage!

Back to more serious matters here at 17 volt reading
from stator eabled  a 62 ma consumption to pole pig
primary.

The spin alone of the field rotor generates 2.1 AC
volts on analog meter and 6.7 ma consumption to pole
pig primary of 26 mh -at- 481 hz. It was formerly noted
in real amperage tests from energized field that the
pole pig reactance was 3.6  times higher than
predicted by formula -at- 481 hz. Applying here to see
comparison with no energized fields in rotation to
model the comparison with the real currents: (although
both are real!)
V=2.1 Volts, I = .0067 A     Z= 2.1/.0067= 313.4 ohms.

This is again higher than the predicted value of 78
some ohms and closer to the previously recorded ACTUAL
Z of 283 ohms.

Sincerely Somewhat Certain of Calculations.., HDN




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Binary Resonant System  http://members3.boardhost-dot-com/teslafy/

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