Dave:
The ballast resistor is a component (in the case of the TR6, a special
length of
high resistance wire embedded in the wiring harness) that drops the voltage
applied to
the ignition coil to around 6v. The thinking goes something like this:
1. When the starter motor is engaged, the battery voltage drops to 6-7
volts.
2. If the coil is a 12v coil, it only gets half the voltage it needs, so
the spark is weak, and the car is harder to start.
3. If you install a 6 volt coil in the car, then when the starter is
engaged,
you have the full rated voltage at the coil, and the car starts
easily.
4. After the car is started, you then have the full 12 volts applied to
the coil.
5. A 12v coil will then have the correct voltage, but a 6v coil will
have too much
voltage, and will draw too much current and overheat (and burn up
points?).
The ballast resistor is switched into the circuit AFTER the starter
disengages. Thus
the 6v coil is operating at it's ideal voltage both when starting *AND* when
running. A 12 volt
coil has the correct voltage ONLY when running.
Thus, a ballasted coil is a more modern design that eases starting,
particularly when
the weather is cold. Later TR6s have the 6v (ballasted) coil.
Vance
---------------------------------------
The most likely way for the world to be destroyed, most experts agree, is
by accident. That's where we come in; we're computer professionals. We
cause accidents. - Nathaniel Borenstein
-----Original Message-----
From: TR6 Triumph [mailto:tr6_1969@hotmail.com]
Sent: Monday, June 30, 2003 12:55 PM
To: 6pack@autox.team.net
Subject: Ballast resistor question
Hi list!
The posting speaking about the bad points possibly caused by lack of a
ballast resistor forces me to ask the questions: what is a ballast resistor
and what exactly does it do in the ignition circuitry. Further, why do some
systems have them and others do not? On the TR6 was it the earlier ones
that didn't have them but the later ones did? What does the ballast
resistor look like and where is it? Thank you.
Sincerely,
Dave Herbert
1969 TR6 and nothing else
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