[tech] Coke machine lights, empty detection, fans

[Nick Bannon]

On Sun, Feb 03, 2008 at 12:00:09AM +0900, Nick Bannon wrote:
> There've been a few Coke machine niggles:
  * some of the neons are burnt out again...

> The neons all have a common rail; and they'll be turned on by 100VAC
> (through current limiting resistors). The common side is about 60V away
> from chassis ground and the switched side (when it's on) is about 40V
> away from chassis ground. That 100VAC signal is cut down to size by a fat
> capacitor/diode/resistor to drive an optocoupler, on the isolation boards.
[...]

So... it turns out that the neon lights are driven with a normal clean
looking sine wave, measured as 288V peak-to-peak with the oscilloscope,
at about 6mA.

Does that mean we've got a low power factor to be reading it as 100VAC
with a standard multimeter? and that things are burning out because we're
underrated for the actual peak-to-peak?

Also... I tripped the White 11 RCD circuit on the dumbterms. Sorry...

Nick.

-- 
   Nick Bannon   | "I made this letter longer than usual because
nick-sig at rcpt.to | I lack the time to make it shorter." - Pascal