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jeeves_m_d
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PostSubject: keyed shaft conductor   Mon Apr 12, 2010 10:17 pm

So my 15lb robot lolcano has its outrunner brushless motor inside the drum with all 3 wires being fed through a rather deep slot through the shaft and this has worked reasonably well. duringr our last fight against uknight the shaft was bent, i feel that the deep keyway was partially to blame but it was mostly the fact that it was a rather large weapon2weapon hit. While making the new shaft we had an idea, why not make the steel shaft itself act as a wire and feed the other to motor leads through the keyway to make the key way less deep. My concern is hitting another robot that uses the frame as ground. would this cause me problems?
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rjw
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PostSubject: Re: keyed shaft conductor   Mon Apr 12, 2010 10:47 pm

don't do it....period

maybe make 3 shallow keyways...1 for each wire....or anything else

is the shaft hollow?...maybe use a hollow tube chromemoly and have the wires come out thru the hole

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jeeves_m_d
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PostSubject: Re: keyed shaft conductor   Mon Apr 12, 2010 10:58 pm

OK do u have any idea as to what would happen if i did? not going to just fairly curious

i do like your idea of shallow keyways
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Cody
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PostSubject: Re: keyed shaft conductor   Tue Apr 13, 2010 11:34 am

i can only imagine bad things.

Your talking about sending an open current across an exposed shaft
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SenaiERI
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PostSubject: Re: keyed shaft conductor   Fri Apr 16, 2010 4:03 pm

NOOOOOOO! The heck are you thinking? You trying to kill someone?

You're not going to be able to insulate the shaft and that's defiantly going to be cunducting through YOUR frame even tho electricity travels the shortest distance. You're almost garunteeing a short when you do that. Just don't do it. Forget the idea all together.

If you want, slot your shaft along the axis and drill a hole (or slot) on the end to feed them in.
Something like this: http://www.megaupload.com/?d=SE9F7Z52
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jeeves_m_d
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PostSubject: Re: keyed shaft conductor   Sun Apr 18, 2010 1:42 pm

It was just an idea...

and i know a number of robots use their frames as ground in the larger classes
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Cody
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PostSubject: Re: keyed shaft conductor   Sun Apr 18, 2010 7:57 pm

when electricity is talked about some people call it hot(positive) and cold(negative) for a reason.

Your ground always has to be to a metallic non pianted surface. If you would make your shaft hot it would basically be an electric fence
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PostSubject: Re: keyed shaft conductor   Sun Apr 18, 2010 9:55 pm

jeeves_m_d wrote:
It was just an idea...

and i know a number of robots use their frames as ground in the larger classes

Which robots? There has been a rule against this for quite a while.
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jeeves_m_d
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PostSubject: Re: keyed shaft conductor   Sun Apr 18, 2010 9:59 pm

well my schools 120 flipper pneumagic from 4 years ago did it and when i asked the senior why they did it they said it was standard
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Jeff L
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PostSubject: Re: keyed shaft conductor   Sun Apr 18, 2010 10:04 pm

From what I recall using your frame as a ground isn't generally a bad idea, but it's against competition rules because students may be prone to improperly wiring a robot (making the frame "hot"). In fact, I'm pretty sure that's how cars are wired (frame used as ground).

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PostSubject: Re: keyed shaft conductor   Sun Apr 18, 2010 10:14 pm

Right, it's just a safety issue. Too many people could not understand that the polarity changes on reversible PMDC motor controllers so they wired their "negative" motor lead onto the bot because hey, it's grounded right? Wrong.
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jeeves_m_d
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PostSubject: Re: keyed shaft conductor   Sun Apr 18, 2010 10:21 pm

i just went through the 15lb and 120lb rules and could not find any rules against grounding the frame
do you guys have a section #?
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PostSubject: Re: keyed shaft conductor   Sun Apr 18, 2010 10:26 pm

Battlebots 5.3 and RFL 6.5 .


It's only allowed if there's a separate switch for the ground.
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jeeves_m_d
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PostSubject: Re: keyed shaft conductor   Sun Apr 18, 2010 10:28 pm

thank you
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PostSubject: Re: keyed shaft conductor   Sun Apr 18, 2010 10:32 pm

np
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