Page 28 - Remembering ISTEL

Remembering ISTEL

Vehicle electrical testing

A large proportion of all warranty
claims are the result of electrical
problems. A computer based vehicle

electrical testing system (or VETS as
it is known) has been developed
jointly by Systems and Ferranti to

help combat these problems.

The traditional method of testing

electrical circuits in a completed car
consists of pressing the appropriate
switch or opening a door, pressing a

button, etc., and seeing whether the
electrical items associated with that
particular circuit work. With

complicated electrics, such as heated
rear windows or bulb failure sensors
and particularly as more and more

electrical circuits are installed in cars these checks are not easy.

VETS provides a much more objective

test of a car's electrical system,
because it measures the actual
current drawn from the battery as

each individual circuit is tested. The
system is linked into the car to be
tested through a probe which is

simply clipped around the car's
battery lead. The probe makes use of
an electrical phenomenon known as

the Hall Effect by which a voltage is
generated in the probe which is
proportional to the current drawn

from the battery. One of the beauties
of the system is that no disconnection
of leads or redesign of the car's

electrical circuit is necessary to use it.

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