Subject: [Shop-talk] Eddy current brake

From: Ian McFetridge <[email-masked]>
Date: Thu, 1 Oct 2015 17:09:53 -0400

Hi,

I'll start by saying this is not shop related, but it is similar to what is
used to brake saw blades.  And more importantly, until I fix it for my
wife, I wont' be spending much time in the shop!

We bought a commercial elliptical trainer in 2002 and it has worked
flawlessly until recently when it suddenly went to full resistance.
Everything appears to still work, it's just feels like it is at level 10
all the time, no matter what I set it to on the control panel.  I've taken
some pictures <https://goo.gl/photos/6aQZhUM9e3UuMZer9> for reference.

Brake - I believe is an eddy current brake that controls the resistance
Controller - is the circuit board and what looks like transformer
and an overall picture of the unit.
Bonus, added picture of the shop I am not in, but you can see the LED
replacement tube lights that I mentioned in prior posts.  The dimmer units
are the very old T12 FL tubes.  Seem to work well, but I need to replace
more of them.

I've reseated all of the connections on the elliptical to no avail.  I also
called the manufacturer, True Fitness, and all of the electrical parts are
obsolete and unavailable.  I would hate to throw it away because
1) it still works, it's just set on full resistance
2) a new one will mean I don't buy toys (or more lights) for the shop for a
while  :)

None of the capacitors appear to be leaking, which was my first thought
after a loose plug.  I don't believe I have the proper equipment to test
further than my multi-meter.  I'm guessing the circuit does pulse width
modulation for the brake.

For the most basic hack, I was thinking of putting a rheostat in the
circuit to the brake to see if I can manually adjust the resistance.  I
have no idea if that would work or what to buy.  There are only two leads
going to what looks like a magnet that I assume is an eddy current brake.

Any input is appreciated.

TIA,
Ian
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From: "Pat Horne" <[email-masked]>
Date: Thu, 1 Oct 2015 16:47:47 -0500

Ian,

Any chance you know how the unit feels when it is turned off? It could be
either fully braked or totally free. I would expect it to be free. If so
the first thing I would do is to unplug the connector that connects the
brake to the circuit board. If the resistance is still the same, there is a
mechanical problem with the brake or a bearing around there.

If it is now free, there is an electrical control problem. Capacitors go bad
and it is not a big thing to just order replacements and solder them in. The
problem may be in the control panel rather than on the board in the photo
though. Things get more complex up there.

Let me know what you find.

Peace,
Pat 

-----Original Message-----
From: Shop-talk [mailto:[email-masked]] On Behalf Of Ian
McFetridge
Sent: Thursday, October 01, 2015 4:10 PM
To: Shop Talk
Subject: [Shop-talk] Eddy current brake

Hi,

<snip>

For the most basic hack, I was thinking of putting a rheostat in the circuit
to the brake to see if I can manually adjust the resistance.  I have no idea
if that would work or what to buy.  There are only two leads going to what
looks like a magnet that I assume is an eddy current brake.

TIA,
Ian

[email-masked]
Archive: http://www.team.net/archive
http://autox.team.net/mailman/options/shop-talk/[email-masked]
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