Lotus Elan

Negative or Positve ground ?

PostPost by: denicholls2 » Fri Nov 03, 2006 4:19 pm

While Roger is correct that the tach is polarity sensitive (as is the
radio and the coil) and may be damaged by reverse current, this does not
mean these components must be swapped out to reverse polarity. The
polarity of their connections must merely be reversed.

Of course, this is made difficult by the practice of using the case to
carry the ground voltage to the unit and the need to isolate the case
from the metal components to which it is grounded. Happily, this is not
a major issue on a glassfiber car as it is on a steel one.

I'm still puzzling over the ability of a DC motor to behave like an AC
motor. I'll take your word for it, but it ain't the natural behavior.
They must have felt that the extra cost of current-sensing logic in the
starter was worth being able to use the same starter regardless of
polarity.

The heater fan motor may be an AC unit or current-sensing as well. But
if you have electric radiator fans, they are usually DC and must have
the connections reversed to run in the right direction. This is a
common fault with the Europa cooling fans, some of which are reputed to
have come from the factory fighting the natural airflow.

-- Doug Nicholls, 54/1822 Ma~
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PostPost by: Gordon Sauer » Fri Nov 03, 2006 7:32 pm

My '72 +2S 130 servos have the sticker of "neg earth" on one of the servos.
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PostPost by: poiuyt » Fri Nov 03, 2006 7:48 pm

It would suck instead of blow!

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PostPost by: frearther » Fri Nov 03, 2006 9:22 pm

Isn't that the definition of Lucas electrics?

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PostPost by: denicholls2 » Mon Nov 06, 2006 2:33 pm

It hasn't cropped up in awhile, but I chuckled all morning when I first
read it, so here it is again in case you missed it first time around.

Q: Why did Lucas go into the vacuum cleaner business?



A: They wanted to have at least one product that didn't really suck.
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PostPost by: Lincoln62 » Tue Nov 07, 2006 12:04 am

And why do the English like warm beer?

A: Because they have Lucas refrigerators.

Couldn't resist.

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