[TriEmbed] Coffee roaster

[Shane Trent]

Brain,

The popcorn poppers often use a secondary heating coil as a dropping
resistor to drop the incoming AC line voltage down to the voltage needed by
the motor. The four diodes around the motor power terminals make a full
wave bridge rectifier to convert the now lower voltage AC to DC to drive
the motor. There is no filter capacitor after the full-wave bridge so the
motor is getting pulsed DC, but the motor doesn't care. The inductance of
the motor and the rotating mass do serve to smooth the current a little.

Shane



On Mon, Oct 29, 2018 at 10:38 AM Brian via TriEmbed <triembed at triembed.org>
wrote:

> > I measured around 16 volts DC going into the motor. It was increasing
> slowly as the motor warmed up.  Started around 15.9 Volts. Does that help?
>
> Sounds like you're in good shape to run it off a DC power supply like in
> the article.  If the popper's own DC power supply is isolated, you could
> just use it.  Note that there's a high chance it isn't isolated.
>
> > It looks like there are two diodes in series attached to each motor
> terminal.
>
> So..  diode-diode-motor-diode-diode?  Hm.  What's between that and the
> AC power input?  It's not critical, but now you've got me curious...
>
> > Do I need to disassemble it more to learn something else?
>
> Probably not, but now *I* want to disassemble it more!  ha
>
> <snip>
>
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