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Help needed with wiring of dual mot's

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LAN_403

E.B.C.

Sat Dec 23 2017, 08:53AM

Registered Member #61923 Joined: Tue Nov 21 2017, 03:27PM
Location: NW Montana USA
Posts: 11

Hi im new to the HV world & have no formal electronic or high voltage training AT ALL. Everything ive learned is self taught through any & all literature i can find. I have the want & the will but still struggle with the math & reading schematics. Ive built 2 smaller coils before this one & had pretty good success. So i decided to try the next step & go with a dual mot psu with a voltage doubler.
I followed "loneoceans tesla coil 2" schematic as best as i could but am stuck on how to run the wiring after the voltage doubler. Im on a very limited budget & have to settle for saltwater caps until i can save up for a real cap bank. Ive used the javascript tc designer but was a little confused with the power calculations box. I'll include what ive got so far & will work on drawing up a wiring diagram of my coil asap. I guess i was hoping someone could let me know if the numbers javascript gave me look okay. & secondly how to finish the wiring after the doubler. Thank you for your time & consideration.content://media/external/file/6108

J A V A T C version 13.2 - CONSOLIDATED OUTPUT
12/23/2017, 2:53:50 AM

Units = Inches
Ambient Temp = 40ÂºF

------------------------------------------- ---------
Surrounding Inputs:
------------------------------------------ ----------
100 = Ground Plane Radius
100 = Wall Radius
150 = Ceiling Height

------------------------------------------ ----------
Secondary Coil Inputs:
------------------------------------------ ----------
Current Profile = G.PROFILE_BARE
1.75 = Radius 1
1.75 = Radius 2
16 = Height 1
35.5 = Height 2
850 = Turns
24 = Wire Awg

--------------------------------------------- -------
Primary Coil Inputs:
------------------------------------------ ----------
Round Primary Conductor
2.25 = Radius 1
3.732 = Radius 2
16 = Height 1
16 = Height 2
2.5408 = Turns
0.25 = Wire Diameter
0 = Ribbon Width
0 = Ribbon Thickness
0.047 = Primary Cap (uF)
6 = Total Lead Length
0.25 = Lead Diameter

---------------------------------------- ------------
Top Load Inputs:
------------------------------------------ ----------

-------------------------------------- --------------
Secondary Outputs:
----------------------------------------- -----------
596.22 kHz = Secondary Resonant Frequency
90 deg Â° = Angle of Secondary
19.5 inch = Length of Winding
43.6 inch = Turns Per Unit
0.00284 inch = Space Between Turns (edge to edge)
778.9 ft = Length of Wire
5.57:1 = H/D Aspect Ratio
18.6145 Ohms = DC Resistance
30857 Ohms = Reactance at Resonance
0.95 lbs = Weight of Wire
8.237 mH = Les-Effective Series Inductance
9.751 mH = Lee-Equivalent Energy Inductance
10.594 mH = Ldc-Low Frequency Inductance
8.651 pF = Ces-Effective Shunt Capacitance
7.308 pF = Cee-Equivalent Energy Capacitance
19.141 pF = Cdc-Low Frequency Capacitance
3.82 mils = Skin Depth
0 pF = Topload Effective Capacitance
128.2588 Ohms = Effective AC Resistance
241 = Q

----------------------------------------------- -----
Primary Outputs:
----------------------------------------- -----------
596.22 kHz = Primary Resonant Frequency
0 % = Percent Detuned
0 deg Â° = Angle of Primary
3.98 ft = Length of Wire
0.62 mOhms = DC Resistance
0.333 inch = Average spacing between turns (edge to edge)
0.365 inch = Proximity between coils
6.75 inch = Recommended minimum proximity between coils
1.406 ÂµH = Ldc-Low Frequency Inductance
0.047 ÂµF = Cap size needed with Primary L (reference)
0.117 ÂµH = Lead Length Inductance
16.804 ÂµH = Lm-Mutual Inductance
0.138 k = Coupling Coefficient
0.128 k = Recommended Coupling Coefficient
7.25 = Number of half cycles for energy transfer at K
6 Âµs = Time for total energy transfer (ideal quench time)

------------------------------------------- ---------
Transformer Inputs:
------------------------------------------ ----------
120 [volts] = Transformer Rated Input Voltage
4000 [volts] = Transformer Rated Output Voltage
0.5 [mA] = Transformer Rated Output Current
60 [Hz] = Mains Frequency
2000 [volts] = Transformer Applied Voltage
0 [amps] = Transformer Ballast Current

----------------------------------------- -----------
Transformer Outputs:
----------------------------------------- -----------
2 [volt*amps] = Rated Transformer VA
8000000 [ohms] = Transformer Impedence
66666.7 [rms volts] = Effective Output Voltage
0.28 [rms amps] = Effective Transformer Primary Current
0.0083 [rms amps] = Effective Transformer Secondary Current
556 [volt*amps] = Effective Input VA
0.0003 [ÂºF] = Resonant Cap Size
0.0005 [ÂºF] = Static gap LTR Cap Size
0.0009 [ÂºF] = SRSG LTR Cap Size
0 [ÂºF] = Power Factor Cap Size
94281 [peak volts] = Voltage Across Cap
235702 [peak volts] = Recommended Cap Voltage Rating
208.89 [joules] = Primary Cap Energy
17280.1 [peak amps] = Primary Instantaneous Current
34.1 [inch] = Spark Length (JF equation using Resonance Research Corp. factors)
810.7 [peak amps] = Sec Base Current

----------------------------------------- -----------
Rotary Spark Gap Inputs:
------------------------------------------ ----------
2 = Number of Stationary Gaps
8 = Number of Rotating Electrodes
1000 [rpm] = Disc RPM
0.25 = Rotating Electrode Diameter
0.5 = Stationary Electrode Diameter
4.5 = Rotating Path Diameter

---------------------------------------- ------------
Rotary Spark Gap Outputs:
----------------------------------------- -----------
16 = Presentations Per Revolution
266.7 [BPS] = Breaks Per Second
13.4 [mph] = Rotational Speed
3.75 [ms] = RSG Firing Rate
1880 [ms] = Time for Capacitor to Fully Charge
0.01 = Time Constant at Gap Conduction
3183.1 [us] = Electrode Mechanical Dwell Time
0.99 [%] = Percent Cp Charged When Gap Fires
936 [peak volts] = Effective Cap Voltage
0.02 [joules] = Effective Cap Energy
75033 [peak volts] = Terminal Voltage
5 [power] = Energy Across Gap
25.5 [inch] = RSG Spark Length (using energy equation)

--------------------------------------- -------------
Static Spark Gap Inputs:
------------------------------------------ ----------
0 = Number of Electrodes
0 [inch] = Electrode Diameter
0 [inch] = Total Gap Spacing

----------------------------------------- -----------
Static Spark Gap Outputs:
----------------------------------------- -----------
0 [inch] = Gap Spacing Between Each Electrode
0 [peak volts] = Charging Voltage
0 [peak volts] = Arc Voltage
0 [volts] = Voltage Gradient at Electrode
0 [volts/inch] = Arc Voltage per unit
0 [%] = Percent Cp Charged When Gap Fires
0 [ms] = Time To Arc Volta

profdc9

Sat Dec 23 2017, 07:24PM

Registered Member #58522 Joined: Tue Mar 15 2016, 08:33PM
Location:
Posts: 50

If you read Loneoceans's web page carefully, you will notice that he had problems preventing the diodes from blowing. The diodes are very sensitive to RF spikes, and apparently Loneoceans eventually abandoned using a voltage doubler in favor of four MOTs in oil. I have managed to get it to work, but I used four microwave oven diodes in series, not two, and I potted the diodes in epoxy so they would not arc between the terminals of the diodes. I also had to build a heavy-duty Terry filter to protect the diodes, including MOVs, capacitors, and large 100 W resistors.

When using a voltage doubler, the power supply delivers power on only half the cycle, so its about 500 mA over only 1/2 the cycle at double the voltage, rather than 500 mA over the full cycle at the voltage before doubling. So the average power is the same but the peak power is doubled with the voltage doubler. I think your current is 0.5 mA and is about 1000 times too low.

Your resonance frequency seems pretty high, and the rotation rate of the rotary spark gap is low.

Dan

E.B.C.

Sat Dec 23 2017, 10:02PM

Registered Member #61923 Joined: Tue Nov 21 2017, 03:27PM
Location: NW Montana USA
Posts: 11

Thank you so much for your feedback i really appreciate it. Any ideas on how to lower the reasonant frequency? & yes i have read loneoceans page carefully (repeatedly, lol) & have been accumulating MO parts just in case i had to go with a quad mot set up. I forgot to mention that im not exactly sure of the power ratings of my mots. The numbers i put into javascript were guestimations i got from looking up similar mots online. Im also unaware of the exact rpm of my arsg motor, i only know its out of a "dyson" vacuum cleaner & is crazy fast! So when i first put in the 20,000rpm into javascript the numbers seemed (to me) to be way to high, but then again im not sure exactly where they should b.
I too have 4 mo diodes in my doubler that i incased in epoxy & used 2 handwound coils for chokes along with the pancake chokes loneoceans described. But i think now ill try the quad mot stack because like he said on his page, ive wasted to much time & money on the dual mot setup. Thanks again.....

Vigh holtage

Sun Dec 24 2017, 02:56PM

Registered Member #61739 Joined: Wed Aug 23 2017, 04:43PM
Location:
Posts: 44

The best way to wire two mots together is to connect the bases of the two mots with an aluminum plate or like i do a 12-14awg wire then connect your ground wire from mains to one of those mots,
This will tie them bolth together in serries and also ground the casrs
This also makes the two high voltage outputs your hv out termanals at +2000 and -2000 for easy connections and low potential across the mots
Now hook up one mot to mains and then hook the other up the same way and test it quikly if there are small to no sparks simply swap live and nutral wire possitions on one mot to phase correctly and test again

It is easyer to just use 4 mots and a balast though, you end up with over 8000vac, problem is they need to be under oil. I use a big ole ammo can and drill out the top to fit my hv terminals and mains connectioms.

profdc9

Mon Dec 25 2017, 07:48PM

Registered Member #58522 Joined: Tue Mar 15 2016, 08:33PM
Location:
Posts: 50

To lower the resonance frequency, you could consider using a somewhat wider/longer secondary coil. I used a 4" PVC pipe. The ratio of the height/width I've read should be about 4:1 to 5:1, so a wider coil also means one can have a longer coil, both of which contribute to a lower frequency.

Another thing you can do with the coil you've got is add a bigger topload. This helps get longer arcs, but you tend to have to increase the primary side capacitance as well. You haven't specified a top load. I took two large salad bowls and placed them bottom-to-top to make an ellipsoidally-shaped load, or you can do the common thing and make a toroid using aluminum dryer duct. If you're looking for big arcs, you're going to need a top load that is going to stretch out, possibly even slightly out over the ends of your strike rails so that you can direct the discharge toward something away from the tesla coil. I would first make sure I had a decent topload, and if the resonant frequency isn't below 300 kHz, work on the secondary coil.

Don't use the chokes. Loneoceans did not, because the chokes along the capacitors can set up a series resonance that can actually increase the voltage of some frequencies. I think the Terry filter approach is the way to go.

If you don't already know this, watch out using MOTs! They are not current limited like NSTs. The amount of current they can deliver can kill you dead in a hurry. Make sure when the thing is powered up, you are well away from it! Also, make sure you include bleeder resistors in your Terry filter just in case to discharge any microwave oven capacitors or the primary capacitor of the Tesla coil!

Another thing I built was a simple high voltage probe using a 50 microamp DC current meter, 40 15-megaohm resistors in series (potted in epoxy), and a full wave bridge made from small diodes. This is helpful to check to see if the power supply is reaching its intended voltage.

Dan

E.B.C.

Tue Dec 26 2017, 12:25AM

Registered Member #61923 Joined: Tue Nov 21 2017, 03:27PM
Location: NW Montana USA
Posts: 11

Again thank you both for your feedback. One of the first things i did when i started this hobby was to read up on all the hazards & safety precautions i should be watching out for & taking. I subscribed to your you tube channel "vigh holtage". & enjoy watching your projects unfold. You seem very knowledgable , as does the other gentleman that replied to my thread. I wish i could see ur quad mot schematic better in the video though, lol...
For some reason thetop load wasnt included in the first calculations but heres the new numbers so let me know if they look a little better. Thanx again
]j_a_v_a_t_c.txt[/file]

profdc9

Tue Dec 26 2017, 07:34PM

Registered Member #58522 Joined: Tue Mar 15 2016, 08:33PM
Location:
Posts: 50

You have only one turn on the primary coil and 0.47 uH primary capacitance. You will need a lot of saltwater caps to get 0.47 uH, probably a whole truckload.

I think you'll have to figure you how much primary capacitance you can realistically get with saltwater caps, and plan for that. I would guess a more reasonable number for salt water caps is in the 0.010 uF to 0.030 uF range. Because of this, you will have a higher impedance primary (the impedance is the ratio of the square root of inductance to capacitance of the primary) so that you will need a higher impedance secondary if you want to get the voltage on the secondary up higher, which means more inductance of the secondary as well.

E.B.C.

Tue Dec 26 2017, 07:57PM

Registered Member #61923 Joined: Tue Nov 21 2017, 03:27PM
Location: NW Montana USA
Posts: 11

Sorry that was after auto tuneðŸ˜°, heres before.
]j_a_v_a_t_c.txt[/file]

profdc9

Wed Dec 27 2017, 12:11AM

Registered Member #58522 Joined: Tue Mar 15 2016, 08:33PM
Location:
Posts: 50

Your inputs to JavaTC are still bad. Learn to work the program and I'll look at it again.

E.B.C.

Sat Jan 20 2018, 04:38AM

Registered Member #61923 Joined: Tue Nov 21 2017, 03:27PM
Location: NW Montana USA
Posts: 11

Im sorry but could you tell me which inputs are still bad? Thank you very much.

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