[tech] Coke machine lights, empty detection, fans
harrymc at decisions-and-designs.com.au
Tue Apr 21 08:50:15 WST 2009
Nick Bannon wrote:
> 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?
I think your meter is correctly measuring 100VAC RMS. The conversion is:
Vpk-pk = Vrms * 2 * root2
(for a sine wave) so 288 volts pk-pk agrees with that.
Neons are typically 70V but very maybe they have been replaced and are a lower
voltage part and/or the limiting resistor is a bit low ?
Did they used to fail prior to installing the empty detector cct ?
More information about the tech