Topica Loopframe_Guzzi Archive


Subject: Re: need help

Author: Patrick Hayes

Date: Aug 26, 2000, 7:05 PM

Post ID: 1702104816


In a message dated 08/26/2000 6:08:52 PM Pacific Daylight Time,
mjon-@yahoo.com writes:

 it would just cause the points to burn, no?
How exactly does a condenser work?

think of the condenser as a little storage battery.

When the points crack open, the primary electrical circuit fails and the coil
discharges a fat spark through its secondary circuit! Simple. However, the
points don't really have an on/off or 0/1 relationship. As the contacts are
pried open by the rubbing block, they slowly and gradually separate. If
allowed, there is a very tiny time slice when they are just barely in contact
and a bunch of electrical arcing takes place (i.e. burned or welded points)
and the voltage gradually changes from 12 volts to 0 volts.

Along comes the condenser. During this very short time slice when the points
would be arcing, the condenser supplies spare, stored electricity so that the
net effect is either FULL CONDUCTIVITY (12v) or ZERO CONDUCTIVITY. In
essence, a true ON/OFF circuit. There is not time for arcing and no buring
or welding of the points. The electrical supply is either 100% or 0% and
nothing in between. The purpose of the condenser is to create the on/off
effect in the electrical circuit. When the circuit is ON, the coil builds
and electrical field (and charges the condenser). When the circuit is OFF,
the field collapses. If you cause the field to collapse INSTANTLY and
COMPLETELY, then it produces a tremendous magnification of voltage and a fat
spark. If you GRADUALLY switch the field off (without a condenser in the
circuit), it will produce VERY LITTLE spark. You need a condenser to insure
that the change from ON to OFF is instantaneous.

The spark is created at the instant that the points OPEN and break the
circuit, not, as some think, when the points touch together.

Patrick Hayes
Fremont CA
EV, EV, SPII, V-65-C, Monza, SuperAlce
MGNOC L-403

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