Fuses; T H E Cut-Out - MG Midget Instruction Manual

Finally, see that the tops of the cells are clean and dry, and that the
ternlinals are tight and smeared with vaseline.
If
the ,equipment is laid by for several months, the battery must be giv'en
a small charge from a separate source of electrical en,ergy about once a
fortnight, in ord,er to ohviate any permanent injury to the plates.
Under no circumstances must the acid he removed from the battery and
the plates allowed to dry, as certain changes take place which rmesult in loss
of efficiency.
T h e battery must n,ever be left in a fully discharged condition, and,
unless some long runs are to be taken, it is advisable to have the hattery
removed from the car periodically and charged up from an independent
electrical supply.
Ammeter. T h e centre-zero ammeter which is incorporated in the
instrument pan'el indicates the actual current flowing into o r out of the
battery. F o r instance, suppose two amperes ar'e consumed when the sid,e
and tail lamps are switched on, and the ignition coil takes o n e ampere, then
if the dynamo is generating at seven amperes the meter will show four amps.
o n the charge side of the scale. This is th,e current in excess of the lamp and
ignition load which is available for battery charging purposes.
Fuses. T h e separate fusing of the various circuits ensures that a short
in any o n e does not affect the rest of the electrical equipment. T h i s is
particularly important when coil ignition is fitted. I t will b e noticed that
the fusing of the lamps is such that there is no risk of the driver being plunged
into total darkness. If both the headlamps, o r the side and tail lamps, o r all
the units connected t o the auxiliary accessory terminal fail to function,
examine the particular fuse protecting them.
Remove the fuse from its holder and see whether there is a break in the
fuse wire. Before replacing the fuse, inspect the units that have failed, for
evidence of short circuits o r other faults that may have caused the fuse to
blow.
If a fuse blows repeatedly, and the m u s e cannot be traced we advise that
the ,equipment is examined by a I,ucas/Rotax Service Station.
The Cut-out. T h e function of the cut-out is to close the charging circuit,
as the increased engine speed alien the car is starting causes the dynamo
voltage t o rise above that of the battery. W h e n the 'engine slows down, the
dynamo voltage falls below that of the battery, and the reverse action takes
place, i.e. the cut-out opens and thereby prevents the battery from dis-
charging itself through the dynamo.
T h e question is sometimes asked whbether the operation of the cut-out in
m y way depends upon the state of charge of the battery. T h e r e is n o such
relation betwseen the t w o ; the sole function of the cut-out is to switch o n the
dynamo with rising engine speed and to disconnect it when the engine slows
down t o below a certain speed. T h e cut-out is accurately set before leaving
the W o r k s and does not need any adjustment, and therefore the cov'er pro-
tecting it is sealed.
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PA(;E
FORTY-NINE