godlovesugly Posted July 8, 2008 Report Posted July 8, 2008 i didnt even realise that making your own dyno was an option. you guys are smart c**ts, i hope one day to have half the smarts that you guys have. Quote
Jason Posted July 9, 2008 Author Report Posted July 9, 2008 (edited) Was chatting to ben last night about this and decied to try out the eddy current idea. I'm going to be using to brake disk so even if it fails i can still go with the disk brake 8| But After a real dummy up setup i managed to get the center core about 5mm away from the disk and the outer cores about 2 cm away. At about 50v unfilted dc i could feel a deffinate resistance in the rotor. Thats using two primary's around one core. I couldn't go up any higher because i could already smell the varnish cooking :) I'm hopeing to have 4 of these 'double primary' cores. Two per disk. I'm not even coming close to drawing the max of 2400W from the wall. And i always got some huge 350v filter capacitors to help if I run out of volts :yak: I plan to run them anyway i just cbfed wiring them up. But this sucker is strong. I was pulling screw drivers towards the core when i was starting to approach 50v. Which is a 'good' sign because it showing I'm wasting a lot of enegery that could be used. My big industrial variac on the left rated 3500W little 1800W rectifier (middle in vice) that manged to only get warm and the eletro. I'm going to have to either reweld the tops of the core or clamp it together becuse the lamites were throwing themselves apart. BTW if any one has old mircowaves they wont to donate give me a PM because I only have 3 cores (Y) and two primaries Edited July 9, 2008 by Jason Quote
Jason Posted July 9, 2008 Author Report Posted July 9, 2008 Just had another play with the caps hooked up. I got a bad feeling i may have already reached the saturation of the disk brake. I duno but i went for broke and cranked to about 100v with no noticeable increase in resistance. Quote
Jason Posted July 9, 2008 Author Report Posted July 9, 2008 This is aculty now looking promising again :) I managed to get the central pole of the magnet withing 2mm of the disk and the outer poles about 1cm. The faster it spins the more resistance it has. I was only spinning it with my hand and once i was getting speed it was quite difficult to keep it there. Also Need mircowaves Quote
camerondownunder88 Posted July 9, 2008 Report Posted July 9, 2008 MMM that isnt varnish mate thats the smell of progress :) Well any left over microwaves ill take as ummm need a new spot welder :yak: Also might be hard but from past experimenting the cooler it is the better the braking effect. is there some way you can chill the disc? How big was the disc rotor just a small one or large? Cam Quote
Jason Posted July 9, 2008 Author Report Posted July 9, 2008 I can only run the magnet for a about 1 min at around 50v. So the disk overheating issue is not the problem. It drawing to much power the twin coils is still almost a dead short. Quote
camerondownunder88 Posted July 10, 2008 Report Posted July 10, 2008 ^^ MMM so electronics need the work hey. Well the experiment I saw used room temp disc yeah worked ok. Then cooled it in liquid Nitrogen OMG stopped friggin fast so I know keeping disc cool can help but for your purpose I am sure it wont matter to much. Quote
Jason Posted July 10, 2008 Author Report Posted July 10, 2008 (edited) It just the increase in conductivity. does any body know the specs on standard brake disks? Like the actual type of iron alloy? IE cast, 4.5% C? Edited July 10, 2008 by Jason Quote
irokin Posted July 10, 2008 Report Posted July 10, 2008 Grey iron... so yea 4.5% carbon and a touch of silicon There are also some brake rotors made out of ductile iron but I don't think theyre very common... Quote
Jason Posted July 10, 2008 Author Report Posted July 10, 2008 (edited) Yeah i could get about 3X the braking power if i used an aluminum rotor for the same magnetic strength, 6X if i used a copper alloy. Aluminum has at least 3X the conductively than run of the mill cast irons. But before anything i need a motor to do some testing :) Edited July 10, 2008 by Jason Quote
Jason Posted July 10, 2008 Author Report Posted July 10, 2008 Just nabbed a 1000 pound load cell for $55 including shipping in the most epic bidding war ive been in lol Quote
irokin Posted July 10, 2008 Report Posted July 10, 2008 Now get my serial controller bish so I can start writing software! Quote
Jason Posted July 10, 2008 Author Report Posted July 10, 2008 (edited) lol because we live in aus we get almost nothing in terms on nifty cool electronic stuff :yak: BUT i just order my free samples of the analog to digital converter chip and the load cell driver chips. Nothing beats getting stuff in the mail, except when its free :) Edited July 10, 2008 by Jason Quote
irokin Posted July 10, 2008 Report Posted July 10, 2008 Free FTW. I'd like to recieve anything in the mail at the moment... Got stuff from google and $360 worth of braided lines missing at the moment gah! I might start on the framework for the software tonight anyway so its out of the way when it comes to the nitty gritty. Quote
Jason Posted July 12, 2008 Author Report Posted July 12, 2008 I just confirmed that telma units atleast use iron for the rotors, this gives me much more confidence :P Quote
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