Stefan thanks for your observations.
The reactor is wound around a 50 kva 3 fase core with the middle leg
removed. and cut in halve to introduce two air gaps. it has 10 sections on
both legs with 2.5^2 mmm and 200 turns, so about 2000 turns. i lost the
calculations, but it was the most challeging part to calculate. it will
not saturate.
I'm well aware of the 10 amp charging current.
i choose a large primairy capacitance to compensate for the relatively low
32 kv end voltage. i think that's pretty high anyway.
The coil should work nicely at 200 bps and anything above should be a bonus.
I added a new post with a hopefully working link to a picture of the coil.
> Maybe you have some saturating issues with your charging reactor, is it
> designed properly to handle the massive charging current without
> saturation?
> Taking your numbers, that gives a maximum power of 143kW @ 700bps and
> therefore a charging reactor inductance of only 518mH. The RMS charging
> current through the choke is 9,9Amps. Designing such an inductor is a
> challenging task, also needs some thick wire to handle 10Amps of charging
> current.
>
> Another "problem" I see in your supply transformer, with only 10kV it
> leads
> to big currents, primary capacitance and much to high break rates in the
> whole system, for processing the desired power of 150kW. For such a big
> system it would be better to use an AC supply voltage in the range of at
> least 15 or better 20kV. Your 80kV caps wouln't have any problems with
> that.
> Regarding maximum break rate, different coilers also reported, that there
> is
> no big improvement in performance above the 400bps level.
> Regarding spark gap, in my opinion it is better, to not exceed 400-450bps,
> but therefore using other tricks to achive a good dwell time and gap
> opening
> speed. By the way, when using more than 4 series gaps in the rotary, it
> also
> becomes a problem to "ingnite" the charging system, when using only 10kV
> AC
> (~14kV DC).
>
> Regards,
> Stefan
>
> ----- Original Message -----
> From: <vam@xxxxxxxxx>
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Sent: Friday, January 02, 2015 9:43 AM
> Subject: Re: [TCML] Need some advice on 150kva sgtc
>
>
>> Hi Carlos.
>>
>> The streamer length increases significantly from 100-200 bps. 200-600
>> there is only a slight increase, probably ads only 50-70 cm to the
>> streamer length.
>> The 2.2kw sparkgap motor can't get the disc to spin over 700 bps.
>> The 125 amp fuses can only take 700 bps for a short while before they
>> pop.
>> The coil jumps to two steady streamers at this power level.
>> We had primairy to secondairy flash over at 700 bps, so the coil is in
>> repair now. This led me to believe that the coupling is already too
>> high.
>> It's .2 acoording to javatc. Playing around with the coupling is not so
>> easy with a 250 kilo secondairy and topload. We think about installing a
>> carjack or something like that.
>> The sparkgap quenches at second notch with airstreamers and firstnotch
>> in
>> ground strikes.
>> Highering the coil will probably help some because it easily finds it's
>> way to the floor. We might ad a smaller topload so we can higher the
>> main
>> topload.
>>
>>> It would be intersting to see how arc length would improve if you lift
>>> the coil up a bit off the ground, and increase the BPS rate.
>>> Coupling is also pretty important on big coils...
>>> Have you experimented with increasing the coupling at all?
>>>
>>> Carlos
>>>
>>> On 2015-01-02 08:13, vam@xxxxxxxxx wrote:
>>>> You got my message spot on Carlos.
>>>> The coil produces constant streamers about 20- 23 feet, or 6 - 7
>>>> meters.
>>>> It's very impressive. But i did make a coil with 1 m winding length
>>>> before, producing 3 meter sparks at 20 kw.
>>>> so i expected around 10 meters with this set up. but 7 seems the max.
>>>>
>>>>> Big machines like this are typically less efficient than there
>>>>> smaller
>>>>> brothers and sisters.
>>>>> I have not taken the time to run the numbers on the info you
>>>>> provided,
>>>>> but if the system is well balanced and in tune and pulling 40kva, I
>>>>> would expect to see 20-25 foot long arcs at minimum.
>>>>> The height of the coil will also be a limiting factor to some
>>>>> degree...
>>>>>
>>>>> I assume from your question that you are not happy with the
>>>>> performance
>>>>> or it did not meet your expectations?
>>>>>
>>>>> Kind regards,
>>>>>
>>>>> carlos
>>>>>
>>>>> On 2015-01-02 06:03, vam@xxxxxxxxx wrote:
>>>>>> Me and some friends built this coil. It's total height is 5 meters.
>>>>>> the
>>>>>> donut is 2,60 by 60 cm. the coil is 65 cm dia with 1200 turns of
>>>>>> 2.5^2mm
>>>>>> installation wire. about 3.6 meter winding length. Cap, DR resonance
>>>>>> 100nF, 80kv 4 in parallel.
>>>>>> We feed it with a 180kva 10kv yz5 transformer. Rectify the lot to
>>>>>> 16kv.
>>>>>> ballast ensures 32kv on the cap. at 200 bps we draw 50-60 amps per
>>>>>> fase.
>>>>>> so roughly 40 kw. Max bps is 700.
>>>>>> Now the question. What kind of spark length should be possible from
>>>>>> this
>>>>>> coil?
>>>>>>
>>>>>> Picture of the coil.
>>>>>> https://www.facebook.com/photo.php?fbid=671287332969054&set=a.110176789080114.14601.100002633816524&type=1
>>>>>>
>>>>>> _______________________________________________
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>>>>>
>>>>
>>>>
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>>
>>
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