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From: sasquevaneach-at-aim.com
Subject: Re: What motor? [TANKS [TANKS]
Date: Sun, 08 Jul 2007 18:22:19 -0400
Reply-To: tanks-at-rctankcombat.com

Thanks guys but I was hoping for something slightly less academic. If those of you who have working tanks could say that, for example, a 50lb tank with 2 x 21W drill motors can manage 4mph, whereas say 115 lb tank with 2 x 24V 750W motors manages 10mph,that would really give me an idea of where to go. I appreciate that speed is affected by a lot of factors- gearing, friction, track style, and is inversely proportional to climbing ability, but if one looks at some ballpark figures and then works around them that seems like a good place to start.

Phil"Just looking for a rough idea" Palmer


-----Original Message-----
From: Mike Lyons <mxlyons-at-cox.net>
To: tanks-at-rctankcombat.com
CC: Clark Ward Jr <ki4gyt-at-gmail.com>
Sent: Sat, 7 Jul 2007 8.53pm
Subject: Re: What motor? [TANKS]

I = V / R
P = V^2 / R = I^2 R

Current is linearly proportional to voltage, so power is proportional to the 
square of voltage and of current.  For a fixed resistance, you can't change the 
relationship between voltage and current.

Power loss is linearly proportional to the resistance of the conductor (e.g. 
wire) and inversely proportional to the square of the voltage (or indirectly 
current if you like), hence the use of very high voltages in long-distance power 
transmission, as you indicated.



---- Clark Ward Jr <ki4gyt-at-gmail.com> wrote: 
...
Actually, Power is proportional to the square of current... I^2 x R = P
 which is why power companies use transformers to jack up the voltage to
tens of thousands of volts before sending it out over long distances to keep
from losing energy in the form of heat (power).  Raise voltage, current goes
down, => I^2R goes down => less heat (power wasted)
...

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