SUGGESTION TITLE: Reverse Polarity Circuit Breaker
a. The suggestion proposes removal of the truck's hot lead to the electrical loads from the starter's battery terminal
and reconnecting all truck electrical needs, through the reverse polarity circuit breaker, to the downstream side of this
circuit breaker. Thus, in case the circuit breaker manually or automatically is tripped with the engine running, the sudden
load disconnect would not cause the alternator to run-away and burn-up.
b. The suggestion cannot be approved for the following reasons:
(1) With the connections following the suggestion, the tripping of the circuit breaker would not insure that the
alternator would not run-away. As reconnected, the alternator would feed its electrical energy to the truck loads. During
after-dark operations, this might work to protect the alternator from trouble by having the alternator feed its energy to the
lights. However, during daytime operations, the normal electrical load (consisting of electrical gages) is insufficient to
prevent a run-away alternator. The same alternator burn-up troubles would occur with the suggestor's hook-up as is
occurring with the original hook-up.
(2) The appearance and location of the reverse polarity circuit breaker contributes to the problem. The circuit breaker
looks like an ordinary, household, toggle light switch, which has been laid on its side. This switch is mounted in plain
view, under the center of the dash panel in the cab and is accessible to anyone who wants to try it and see what it does.
It can also be tripped by personnel, swapping driver and co-driver seats, by brushing against the exposed toggle when
they negotiate the obstructed paths. Many alternator diodes could be saved by relocating the circuit breaker to an
inconspicuous position underneath the dash. The relocating should be out of the way of ready access and with the toggle
out of sight.