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Finn Hammer

Tue Apr 06 2010, 04:17PM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

May there sound a big hooray, and a 'Hats Off', for the automotive industry!

Thumper has 2 DC gear motors. They'r not automotive types, but.....

-they need to be controlled. Forward, reverse and in PWM. Nothing fancy, but still...

In comes the automotive search parameter and Viola!: The mighty VNH3SP30-E.

A full bridge with integrated controll logic, charge pumps, over current protection, diagnostic and whatnot.
Good for 30A @40V too.....

Most pins are power in, gnd and power out, only 3 are for controll:
2 of them determine fwd, rev or brake, the 3rd. takes PWM signal.
This chip mates directly with the AtMega 328 that's going to controll them, via a fiber optic link.

Daniel and Simon are coding till their fingers bleed, to make this remote controll communicate via serial protocol

A bottom frame of rectangular stainless steel pipe was designed and manufactured during easter, it completes the primary mainframe to a point where I can climb it without doing any damage.

All in all a good easter's worth og build and design.

Cheers, Finn Hammer

Dr Hankenstein

Wed Apr 07 2010, 03:54AM

Registered Member #1642 Joined: Sun Aug 17 2008, 11:36PM
Location: Black Canyon City
Posts: 96

Finn,

That's one rockin' design....always something innovative from you! (But then, I wouldn't expect anything less) I really like the pheonolic touch.....now that's money; dude! Awesome that you will be able to re-couple on the fly...I'm sure we are all going to be very jealous indeed. What a research tool you have here.

Thank's for sharing, big dude!

Woo

Dr. Drone

Thu Apr 08 2010, 04:17AM

Registered Member #290 Joined: Mon Mar 06 2006, 08:24PM
Location:
Posts: 1673

Finn Hammer

Sun Apr 18 2010, 05:11PM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

I am the first to admit that building coils can lure the builder into dead ends, where there seems to be no solution to manufacturing challenges, often at the very end of a complicated project. This frequently reduces the master builder to a cursing and nail biting meanace, feared by family, neighbours and passers by.
I was starting to look a lot like that, recently.
Reason for this was, that the day for winding the copper tube into a primary coil was rapidly approaching, and I had absolutely no clue how I was going to lure this thin walled 22mm tube into accepting the proposed diametre of 560mm, without it becoming completely flat.

My coiling buddy and worthy adversary, Daniel Uhrenholt, was by my side in this dire moment, and with his help, the tube was preliminarily reduced to a 580mm diametre coil, as seen below:

After this was done, an afternoon passed, carefully nudging the coil into the primary supports, and tying them temporarily with Tiewraps:

It was now time to drill the holes that secure the primary coil to the supports:
A special drilling jig was fabricated out of a nice block of aluminum, and 2 drill bushings were turned, so that I could drill the holes.
The holes have to be aligned to the center of the support, as well as the center of the tube, so that when the screw is inserted, the tube is in the correct position, and so that there is correct clearance for the tapping point to pass.

Here you can see the jig entering position to drill the first hole, 5mm, to allow the screw head to enter the tube:

Next, the jig in position, showing the drill bushing for the 3.5mm hole at the inner perimetre of the tube, where it is fastned to the support:

Last picture today shows the coil liberated from the first row of Tiewraps, and the coil permanently secured to the former. You can see that it has a screw loose, I dropped one screw in there.
The tapping point is going to pass over these holes, but I can live with that.

Since the motors that position the tapping point and the coupling position are controlled by an embedded microprocessor, we can now get a feature implemented, that needs attention:

When tapping to a different primary frequency, the coupling also changes due to the change in primary coil geometry. This changes the coupling too.
The Microprocessor will be programmed to change the coupling to maintain it's desired value, during tapping the frequency.

A very productive weekend, thanks to Daniel and greetings to you all.

Cheers, Finn Hammer

ScotchTapeLord

Sun Apr 18 2010, 07:16PM

Registered Member #1875 Joined: Sun Dec 21 2008, 06:36PM
Location:
Posts: 635

Great to see it coming along, but isn't that tap a bit close to the next winding?

Finn Hammer

Sun Apr 18 2010, 07:30PM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

ScotchTapeLord wrote ...

Great to see it coming along, but isn't that tap a bit close to the next winding?

If what you refer to as a tap is the aluminum drill jig, then absolutely yes!

But it is a drill jig, not a tapping point.

Here is the tapping point:

It is a novel 'tapper', riding on the inside of the coil on ball bearings, to allow tuning the coil on the fly. See also further up.

Cheers, Finn Hammer

ScotchTapeLord

Sun Apr 18 2010, 09:18PM

Registered Member #1875 Joined: Sun Dec 21 2008, 06:36PM
Location:
Posts: 635

Ohh... okay! Gosh, that sure looks great...

Linas

Mon Apr 19 2010, 07:02AM

Registered Member #1143 Joined: Sun Nov 25 2007, 04:55PM
Location: Vilnius, Lithuania
Posts: 721

i have question
Predictor can compensate driver delay , but does that delay depend of operating frequency ? Because my driver has constant delay for various frequencies so if i change oscillation frequency, do i need tune predictor again ?
th

Finn Hammer

Mon Apr 19 2010, 04:50PM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

Linas wrote ...

i have question
Predictor can compensate driver delay , but does that delay depend of operating frequency ? Because my driver has constant delay for various frequencies so if i change oscillation frequency, do i need tune predictor again ?
th

Linas,
I frankly donÂ´t know, so I hope someone with better circuit theory will chime in here.
Terry Fritz did some calculations, and I seem to recall that he said it was pretty much "spot on" within the frequency shift that could be expected due to streamer loading.
*I* adjust the Predikter to the frequency that the coil is Idling at, and hope it stays good during streamer load.

The field around Thumper is so grand, that even if it is running with just enough voltage in to run, then I get arcs to ground from my toes in sandals! So I have not been able to check with the scope real close.
This will change with the new faraday suit, which will allow me or Daniel to monitor the timing at full output.
I am sorry that this is the best i can doo at the moment.

I love the work you are doing, and wish I could take half as well lit pictures as you do!

Cheers, Finn Hammer

Finn Hammer

Sun Apr 25 2010, 08:02PM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

The Thumper mainframe is coming along nicely:

Today, Daniel generously milled out what has become the golden standard of controll gearing for DRSSTC tapping point positioning, since there are identical elements in his Diable Tonnere coil: The pinion and internal gear:

This allowed me to wrap up the Tapping Point for Thumper. It still has to pass the high current test, which will be performed when I receive the cool-amp Conducto Lube silver powder lubricant:

But just to stir your envy, not penis envy this time, but something more powerful, Tapper-envy, Here I give you the preview video of what just might become the future standard of DRSSTC real time tuning:

Cheers, Finn Hammer

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