[R-390] Line Filter

[Drew P.]

Bill,

The capacitors DO pull real power, that is, when they are failing.  The caps then release their magic smoke and fire.  Yet another compelling reason to rebuild/replace the filter module.

Goto r-390a.net and reference Wei-i Li's "Pearls of Wisdom", a treasure trove of knowledge on this topic and all others R-390, painstakingly distilled from this forum over the years.

Drew


> 
> Roger,
> 
> You're one of the best on the list, so I hate to even
> mention this.
> 
> Capacitors to not pull real power. If they did, they'd heat
> up.
> Instead, they draw reactive power which doesn't show up on
> a watt
> meter. Think of them as tiny power factor correction caps.
> 
> The GFI doesn't know that the current is out of phase with
> the
> line voltage, and neither does your body when you put
> yourself
> in the current path. Your wattmeter does know that the
> reactive
> current is out of phase, so it doesn't show cap current
> times
> line volts.
> 
> Years ago, when 2 mfd 600 V bathtub caps were cheap, you
> could
> use one to light a pilot lamp from 120 VAC without the heat
> of a
> dropping resistor. The lamps didn't last long if they were
> turned
> on and off frequently, due to the initial charging current
> if the
> switch closed at the peak of a line cycle. Never tried a
> small 
> series R to drop the surge current, though.
> 
> Bill Hawkins