Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: volts and amps

A std. modification of old VW type 1 (bugs) was from 6 V. to 12 every thing was changed to 12 v. (lamps, radio, ( in my case, I removed the 6 => 12 volt inverter), bat. and generator - duh, etc. BUT
not the starter, as its use is intermittent, and, therefore, because of its thermal capacity, it will tolerate the overheating. Quicker starting too! The solenoid didn't fail in the five years I
owned the car after mod.

bc

P.s. Before I did this, I had run a separate (in parallel) ~ # 6 cable to the starter, because with age the starter system wouldn't work intermittently. Everything runs "brighter" with the 6 => 12
mod. because the wiring is still "bigger" for the 6V. I assumed that the reason for 6 => was to save on expensive Cu. The power delivered by the gen and batt. remains the same, so no saving there?
However, though the V and internal R both double, the internal power loss is halved.

bc



brian whatcott wrote:

At 10:27 7/14/00 -0500, Doug C wrote:
...
If a device is "designed for 4.5 V", to me that says its internal
resistance is much higher than that of the intended voltage source and
that voltage will normally dictate the current as a dependent parameter,
not as an independent parameter.

\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/~\_/

Doug Craigen
http://www.dctech.com/physics/


John D mentioned an exceptional case earlier -
the car headlamp on the dry cell supply.

Here are one or two more:
The starter motor used on 12 volt cars will likely burn out if
driven with a stiff 12 volt supply.
The coil on some older cars (Fords in particular) would also burn out
if their dropper resistor were somehow shorted for long
(for imagined spark boosting?).

There is a move to 42Volt auto systems, in progress now.
This is happening for much the same reason cars moved to 12V
from 6 V systems mid century.

brian whatcott <inet@intellisys.net> Altus OK
Eureka!