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Oxy-Acetylene Welding and Cutting - Electric, Forge and Thermit Welding together with related methods - and materials used in metal working and the oxygen process - for removal of carbon by Harold P. Manly
page 134 of 185 (72%)
drawing it away quickly. If no sparking is produced, the secondary circuit
is free from ground, and you will then look for a broken connection in the
circuit. Some caution must be used in making the above test, as in case one
terminal is heavily grounded the testing wire may be fused if allowed to
stay in contact with the die.

_The Remedy._--Clean the slides, dies and terminal blocks thoroughly
and dry out the fibre insulation if it is damp. See that no scale or metal
has worked under the sliding parts, and that the secondary leads do not
touch the frame. If the ground is very heavy it may be necessary to remove
the slides in order to facilitate the examination and removal of the
ground. Insulation, where torn or worn through, must be carefully replaced
or taped. If the transformer coils are grounded to the iron core of the
transformer or to the secondary, it may be necessary to remove the coils
and reinsulate them at the points of contact. A short circuited coil will
heat excessively and eventually burn out. This may mean a new coil if you
are unable to repair the old one. In all cases the transformer windings
should be protected from mechanical injury or dampness. Unless excessively
overloaded, transformers will last for years without giving a moment's
trouble, if they are not exposed to moisture or are not injured
mechanically.

The most common trouble arises from poor electrical contacts, and they are
the cause of endless trouble and annoyance. See that all connections are
clean and bright. Take out the dies every day or two and see that there is
no scale, grease or dirt between them and the holders. Clean them
thoroughly before replacing. Tighten the bolts running from the transformer
leads to the work jaws.


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