Question about current draw

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Question about current draw

Post by HACHI-RYOKU » Sun Jan 15, 2006 3:58 pm

Does binding in the gears draw more current to overcome? Just curious.

I was thinking about the difference between 2 of my cars. One is a Mini-z MR-02 and the other is a Gen 1 Xmod. They both have a 2 X 3 stack of 7317's and a plasma atomic motor. The MR-02 has a 9 tooth pinion and the Xmod has a 10 tooth pinion. Both are using neo mags in the motor. The MR-02 blew it's fet stack after some heavy racing for about an hour and a half and I can run the Gen 1 Xmod all day without any problems. The gen 1 Xmod's gears are not as smooth as the MR-02 by far. It's noisy, clunky around the turns and heavy. The Mini-z is smooth, fast, corners well and is very light compared to the Gen 1. It's by far the better car. But, the same motor-fet setup in the MR-02 pooped itself, while the Gen 1 keeps going like the energizer bunny. I know comparing these cars is like comparing apples to oranges, but I still think about the question. The Gen1 Xmod's gears are as smooth as I can get them, but they are not as smooth as the MR-02, which means, that besides the other disadvantages of the Gen1, there is more resistance in the drive train. But, would more resistance = more current draw? If so, then why would my MR-02 blow its fets before the Gen 1 Xmod?
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Post by betty.k » Mon Jan 16, 2006 12:28 am

Does binding in the gears draw more current to overcome?


yes.

personally i think you may have bummed your fetmod on the z. possibly overheated one or all during the process. maybe they got damaged in the beginning when it was acting weird.

that's just speculation on my part, but my xmod works the electronics harder than my mr02.
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Post by HACHI-RYOKU » Tue Jan 17, 2006 6:26 am

:???:

I may have killed them from the beginning. It was a bit of a hassel soldering around that block box with the soldering iron that I have. I'm currently looking for a different soldering iron with a smaller tip. The iron that I have now is great until your trying to work around other parts. Thanx.
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Post by ph2t » Tue Jan 17, 2006 5:30 pm

Most likely mate it's the fet stack soldering on the side of the IF filter box (YOKO box thingy).

If pins 2 and 4 aren't all connected then only one or even two of the mosfets in the stack are actually getting turned on. If not all mosfets are getting turned on then only the ones that are working will take the current. This is most liekly what happened and therefore why it blew up.

Fet stacking on the kyoshos PCB's is a bitch for the very reason of the IF filter box being so close.

Another way to do is is put the fet stack together seperately and then put them on in one go. It's tricky but this way it makes it easier to ensure that all pins in the stack are connected well.

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Post by HACHI-RYOKU » Wed Jan 18, 2006 12:50 am

Do they even use pins 1 and 3? I noticed you don't use those spots on your external fets.
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Post by ph2t » Wed Jan 18, 2006 12:53 am

Use, definately use all pins. 1 and 3 are + and ground on the fets. Those that are on nelly are wired direct from nelly's pcb.
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Post by HACHI-RYOKU » Sat Jan 21, 2006 3:33 pm

Well, got some new fets in there. Running good again. I took a good look at my blown fets and it looks like the top fet's pin # 2 on the fets next to the black box wasn't touching the pin below it very well. I guess it was just sloppy soldering on my part. I picked up an $8, 15 watt iron from rat-shack, which was alot easier to work with than my 30~80 watt butane iron. I took my sweet time and made sure to get them all connected correctly. I put one on at a time and tested it with a volts meter after each one. Now it's back in the game.

Allready broke of a little bit of the body on the front. Oh-well, what's a good car without some battle scars, right? This is actually my beat-up body. I picked up a green Takata Dome with the set originally, but I couldn't bring myself to beat the piss out of that one. I'll probably do some body work to this one and give it a fresh coat of paint soon to spiff it up some.

Can't comment enough on those Gandini foams though. Those things rock and there not even getting worn down yet. I don't like blowing that much dough on tires, but they are worth every penny. I would recomend the soft foams in the back and the medium or hard foams in the front. It makes a little understeer, but it's better than flipping. This setup is still better than the other tires I've tried. You were right PH2T, I'll never look back. The oil shock is also a must in my opinion.
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Post by SuperFly » Sat Jan 21, 2006 4:12 pm

You guys are running the foams on concrete or asphalt, right? I've tried foams on RCP and just couldn't get any hookup.

Hatchi- I'll snap a pic of my Takata NSX to show you what it looks like after a year of hard driving. It's pretty beat to crap, and 100% of the damage is from other cars (actually, just one other car), as it's only been driven on RCP with foam rails.
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Post by crazydave » Sat Jan 21, 2006 6:34 pm

Assumeing 1/28th foams are the same as other scales, which I don't see why they wouldn't be... they work good on concrete, but pick up dust quickly. They work great on asphalt, but you'll tear them up in a couple runs if its rough asphalt. Ideally they're intended for carpet tracks, and those guys usually use traction compounds, to make the foam soft and tacky. So the track also gets sticky with compound.

I'd suggest checking Tower for some traction compound, but I'd test a small spot on your RCP track first to see how it reacts with it.
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Post by HACHI-RYOKU » Sat Jan 21, 2006 8:50 pm

crazydave wrote:Assumeing 1/28th foams are the same as other scales, which I don't see why they wouldn't be... they work good on concrete, but pick up dust quickly. They work great on asphalt, but you'll tear them up in a couple runs if its rough asphalt.


These Gandini's are different CD. They last much longer and they are sticking to my kitchen floor better than stock Xmod tires. I don't think they're the cure all, but they are the shizzle. They also don't pick up dust as much as regular foam. In fact, the more I run them, the stickier they get. It's like they needed to get roughed up a bit, which would make sense. So far they still look new, but the Xmod evo that I've been running about the same amount is showing some wear on the tires. I'll retract this statement if they crap out on me, but for now they're running like champs.

Superfly, I haven't tried these on RCP. PH2T or Betty may be able to give you more essay on that. They are working beautifully on a waxed tile floor at the clinic I work at, on my kitchen floor and outside on the street or sidewalk.

Also, I would love to see a beat up Takata Dome.
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Post by betty.k » Sat Jan 21, 2006 9:51 pm

we've never run on a rcp type track before but the sydney guys found some tiles locally and put one together, try asking them.

those foams are durable, i go through 2 sets of rubber narrow front tyres for every set of wide rear foams.
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Post by HACHI-RYOKU » Tue Jan 24, 2006 5:29 pm

Here's a pic of the Gandini foams and a pick of stock Xmod EVO tires. They've both been run pretty much the same amount.

Gandini Foams
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Xmod EVO stockers
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Sorry the Xmod EVO pic is a little blurry, but you can still see what I'm talking about.
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Post by MafiaS » Tue Jan 24, 2006 5:35 pm

Nice...

video - VID..DI...YO! ...Hachi try and get them in some motion big guy.

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Post by ph2t » Tue Jan 24, 2006 6:19 pm

here's a good video for mr02, concrete setup action!

http://bitpimps.lixlink.com/pages/phpFo ... php?t=6905


hachi, you using the 8.5mm rims on the rear? man, get the fatty 11mm!


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Post by MafiaS » Tue Jan 24, 2006 7:10 pm

Trust me ph2t...I watched that video enough times. I absolutely love it man. Tight racing too. Thanks.

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