THE CAR DYNAMO.

Press, Volume LXIX, Issue 20907, 14 July 1933, Page 16

THE CAR DYNAMO.

HINTS ON UPKEEP. Few of the components of the chassis are more dependable and call for less attention than does the dynamo or generator. In fact, the car owner can generally forget its existence, except that, when the bearings of the armature shaft are not packed with lubricant which will suffice during the normal life of the car, a few drops of light oil should occasionally be injected into the "oilers" provided. The real pulse of the dynamo is the ammeter, and one should make a habit of glancing at its dial from time to time, so that any erratic movement of the needle may be noted. When the taurine is < running steadily the ammeter needle should not oscillate, but remain steady either on the "charge" or "discharge" side, according to the rate of revolutions. Cases have been observed in which the dynamo fails to charge under ordinary conditions, but functions properly after the contact points of the cut-out have been closed by hand. That circumstance implies a fouled commutator, on which a Aim of dirt, probably attracted by over-lubrication, has settled, and the fault is easily put right by wiping the segments of the commutator with a rag which has been moistened with petrol. Another rather baffling condition Is that in which the charging rate Is steady at low speeds, fluctuates at high speeds, and returns to zero when the engine is driven very fast The ?>robable explanation is that the armaure shaft which carries the commutator is running eccentrically, with a result that the brushes are thrown off the commutator, and so fail to make good contact.

If the dynamo is driven by belt from the engine, looseness of the belt and consequent slipping might affect the charging rate, and care should be taken to keep the belt duly tight. Oil on the commutator and the brushes will naturally cause trouble, and so, too, will loose contacts or the protrusion of the mica insulating strips between the segments of the commutator. Gradually the brashes wear down, until at last the springs which press them against the commutator cannot do so firmly, and the brushes do not make good contact. In such a case the brushes must be renewed. DANGER IN CLOSED CARS. That it is extremely dangerous to drive in a saloon car which is completely closed, and therefore unventilated, is the conclusion reached by a committee of medical experts which recently investigated an accident on the Great Southern Highway of New South Wales. In bad weather a doctor was driving along the road in a completely closed saloon car. He became drowsy, and suddenly lost consciousness. The uncontrolled car crashed into a tree, and he was seriously injured. An investigation disclosed that carbon monoxide from the exhaust had made its way up through the floorboards into, the body of the car, where it remained. Carbon monoxide, which occurs fairly freely in the exhaust gases, is the highly poisonous gas which is also produced by defective bath-heaters. One of its most dangerous features is that it has neither colour nor smell, and the victim is therefore unaware of its presence until he collapses. It is evident that even in the worst weather, and at the risk of creating a slight draught, at least one window of closed cars should be kept open sufficiently to maintain a circulation of air in the body.