Oil Coil With Metal Body
Page 57
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ONE of the new products which will be seen at the International -Motor Show is the Delco-Remy oil-filled coil, produced by a concern which took a large part in pioneering coil ignition and now claims to be the largest manufacturer of vehicle electrical equipment in the world. In Britain, this concern is known as the Delco-Remy-Hyatt division of General Motors, Ltd., 111, Grosvenor Road, London, S.W.1.
This special coil is not an untried product. It was first produced in 1939 for the American market and over 20m. units have been put into service as original equipment and replacements. The decision to supply the British market was taken in 1949 and after two years of development and planning, production of the coil started in a new plant using special machinery.
Two of the major causes of failure in ordinary ignition coils are said to be moisture and heat. During operation there is a repetitive cycle of raising the internal temperature and cooling it. This may result in the coil breathing, as the air, when hot, expands and is expelled, whilst on cooling a partial vacuum draws in air which may be moisture laden. Condensation may then take place and cause an accumulation of moisture. This moisture could set up a corrosive action, break down insulation and cause loss of electrical energy, flashing or failure.
It is claimed that oil filling is the only real answer to this problem and in the new Delco-Remy oil-filled coil, the presence or entry of any form of moisture is positively excluded, whilst all component parts are dehydrated before assembly. The coil is filled with oil under vacuum and is then hermetically sealed. The container is of seamless. deep-drawn metal to withstand the heavy sealing pressure required in production.
The metal case has another useful purpose, for it assists in dissipating the heat removed from the windings by the oil. The coil is also specially wound to balance the output under varying loads and engine speeds. Priced at £1 16s. each coil is guaranteed for two years.
"The Commercial Motor" has tried out a 12-volt oil coil for some weeks with every satisfaction: