![\"\"](\"\/pics\/pq2\/pq2_10.jpg\")
<\/a><\/p>\nFrom United Hobbies are the replacement internal parts. After some idea juggling, I settled on some 460mAh packs rated for 15C discharge. This of course gets me an incredible 6 amps of maximum current, but given my intention to run everything in the bot mildly, should not get in the way.<\/p>\n
These packs are 3S each, and I will remove one cell from each pack, then series the remaining to yield 4S x 460mAh.<\/p>\n
The new 10A controller is unbelievably small – MUCH smaller than Pop Quiz’s current 10A controller by far. It has one SO-8 FET per leg of the motor driver bridge.<\/p>\n
Still missing is the micro-receiver and drive ESCs. These parts are contingent on whether or not I can shove the old ones into the new design.<\/p>\n
PQ2 drive motors! This is a side-by-side comparison of the stock Mabuchi slot car motor, and the neodymium-tuned one next to it (On the right). The “freewheeling noise” of the “enhanced” motor is substantially lower. According to my R\/C meter, it draws an obnoxious .4 amps no-load, but oddly enough, runs smoother and with significantly less brush arc than the stocker. I wish I had some real equipment such that I can collect real data instead of jamming my finger into the rotor to see how easily it stops (Alot harder to stop the new motor, by the way!)<\/p>\n SDP-SI<\/a> is out of stock on the exact size gear I need to fit the new drivetrain. Go figure – I’ll keep bugging them until they are restocked.<\/p>\n With those little details on hold, it was time to work on the new motor.<\/p>\n …but alas, disaster strikes even before starting.<\/p>\n After popping the stators out of the motors I intended for the bot, I discovered they are in fact 3mm<\/strong> thick, not 4mm like I had visually inspected (Note that these aren’t the “flat motors” from the last update, but rather some HDD motors I had bought in 2006)<\/p>\n This was quite bad, as I had sized the design for a 4mm tall stator. This isn’t to say 3mm won’t work, since small fits in place of large, but would cost me some power as well as style points.<\/p>\n What ensued was a night of terror levied upon a box of old hard drives sitting around MITERS. I went through one of every unique make to see if they had usable spindle motors. There were only 4 brands and models in total – the rest were duplicates.<\/p>\n (MITERS obtained this after some server cluster on campus dumped their old hardware)<\/p>\n I hate new stuff. I really do. Because they ALL LOOK AND FUNCTION ALIKE on the inside. Not a single 4mm, 12 pole motor was found out of four drives. The only 4mm stator was 9-poled and 20mm in outer diameter, totally unworkable. Of course, going through more was only going to be redundant, so I called it a night and just worked on the motor frame itself.<\/p>\n I have some older (1990s) hard drives hiding under my bed that might prove more useful. Old things tend to have bigger motors. Or I could just harvest some plates from one stator and transfer them over.<\/p>\n Result of the Night of Terror. The other MITERers were, of course, glad to act as parts vultures, stripping the discs, magnets, RW heads, and various random bearings and spacers. I wonder how many cents I can get if I recycle the casings.<\/p>\n Time to get down to business. Behold, the sketchiest sawing setup that has ever existed.<\/p>\n I needed a chunk off this 8 foot long, 1.6″ diameter steel pipe. There wasn’t really an easy way to handle it besides propping it up on the work table and using the abrasive saw.<\/p>\n Problem was, there wasn’t really a sawhorse or structure that could easily fit in the space provided. The solution was to prop it up with a wooden board and just hope nothing moves.<\/p>\n Nothing moved, but the effort proved fruitless as the inside of the steel pipe, when cleaned of rust, was around 1.3″ diameter. I need a 1.295″ ID on the magnet ring, and would rather trim outwards from a smaller pipe.<\/p>\n D’oh.<\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n<\/a><\/p>\n