New year – new toy

It had become clear that replacing the entire roller/resistance unit would require more machining accuracy than I was capable of with the wood lathe and pillar drill. So I’ve recently treated myself to a small engineering lathe (please excuse the shoddy mobile phone picture).

lathe1

Now, it hasn’t entirely escaped me that I’ve just spent more on a lathe than I would have done on an ergotrainer! So I guess now this project is more about scratching an itch than it is about budget..

Am just in the process of gluing up a new MDF mounting for the pillow block bearings, then will set about machining a new roller.

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2 thoughts on “New year – new toy

  1. Tony

    Hi, just recently found his while looking for similar projects, firstly congrats on the shiny new toy :-) And congrats on your success so far :-)
    While reading I had a few thoughts/questions pop up, which may hinder or help you in some way or other!!!
    1. Does doubling up on magnets double up on stopping/resistance power?
    2. I’ve only ever seen demos of eddy brakes using one disc with magnets, now a magnet has two poles, so effectivley only one pole is being utilised for ‘braking/resistance’, so my question is this.
    If you used the one magnet but had a ‘disc’ at each end, would this double the ‘braking/resistance’. If this is the case then it could possibly be a power saving for your electronics. (this could naturally also lead to using three discs with your two magnets sandwiched between)
    I’m guessing your existing power meter may be able to help with the answers, or if any physicist can give a good/easy answer…

    1. jescombe Post author

      Hi Tony, thanks!

      1. Yes, adding more magnets should increase the resistance. I think I’ll have room for probably 3 pairs at the sizes I’m aiming for.

      2. What I was looking for was the strongest magnetic field directly through the disk, perpendicular to the direction of rotation. So the disk was effectively sandwiched between the N & S poles of a magnet, with as small as possible gap. My current arrangement has one winding on either side, with the poles on the ‘outside’ (for want of a better term) of each magnet joined on a ferrous core.

      I agree there is loads of room for experimentation, I have seen images where the disk is sandwiched between two coils like mine, and also images where two disks sandwich a number of coils. The thickness of the disk is something I’m also currently wondering about – have no idea what would be optimal here.

      Regards,
      Jon.

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