[TriEmbed] Coffee roaster

[Brian]

Well there you go!  No isolated (or even regulated) DC inside the 
popper, which makes sense from a cost standpoint.  I've never 
disassembled a hot-air popper, so I had no idea what would be in there.

-B

On 10/29/18 11:03 AM, Shane Trent wrote:
> 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 <mailto: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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