Electric tidy-up cuts downtime
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ELECTRICAL failures, either directly or indirectly, are by far the most common cause of commercial vehicle breakdowns. So many of the vehicles systems are controlled by relays or other electric components and these are often designed on a fail-safe basis.
Thus if there is a malfunction, a warning buzzer or light comes on, which effectively means the vehicle has to stop, as otherwise there could be a real problem. Many failures which do not actually prevent the vehicle from being driven can nevertheless render it illegal. With the strict enforcement of 0licensing regulations, few operators are prepared to take the risk of a GV9, for say, one tail light not working.
Most manufacturers accept that electrical faults are bad news as they impinge on the vehicle's basic reliability. Invariably all the components of the electrical system are bought in from outside suppliers, so to a degree the truck builder has little control over their inherent reliability, or lack of it.
Electrical component makers do of course strive to improve their products. We've seen heavy-duty bulbs which take the' knocks and shocks of cv usage and modern plastic cable which is less likely to crack or be accidentally damaged. Nevertheless, electrical defects still continue to be a major source of nuisance and cause many hours of downtime.
At last one vehicle manufacturer has grasped the nettle and decided to do something about it. For the last two years Fodens have been trying a new form of cable conduit — Truck-flex — which keeps the loom isolated, and insulated, from the worst effects of wear and tear.
At the same time Fodens took the opportunity to tidy up the whole electrical system, culminating in the set-up now in use on its latest grp /steel cabbed vehicles. Basically the company decided that there were too many exposed electrical points. The loom was covered in connectors and breakouts or tappings. Straight away the Foden engineers re-located those points and connectors, made by A. B. Connectors, Glamorganshire, that they could and put them inside the cab, shielded from wet.
All are connected by Lucas terminals on terminal strips and are grouped together with all the negatives together. The whole system is of the isolated return type. To allow positive yet water-proof connections from the central connections, Fodens use Cannon bayonet fittings. These are waterproof to a depth of three fathoms so they are more than adequate for normal .use.
To carry the cables along the chassis and to various components, Truck-flex is used in two guises and in sizes from 12.5 to 25mm (0.5 to lin). The black coloured Truck-flex has a fire resistance of up to 215° and so is used for engine applications, while the grey-coloured version is for normal chassis use. All junction boxes are neoprene sealed and the Truck-flex itself is made of a corrugated neoprene inside covered with a neoprene sleeve. It is resistant to damage and to oil and diesel.
In addition to making sure the basic wiring system is as free from breakdown problems as possible — circuit breakers and an audible earth warning system are also incorporated — Fodens have tried to make things easier in other ways.
For a start the whole new system, which also has a battery master switch built in, conforms to petroleum regulations, so all that's required by petrol companies is a fire screen at the rear of the engine.
To allow simpler radio fitting, an aerial is supplied ready connected. This cuts radio fitting time from hours to a matter of minutes and it is fully suppressed. Coupling lights and a roof sign too have the wiring built in, so only a blanking plate has to be removed in each case. All this speeds the fitment of extras.
As far as the,lamps themselves are concerned, Fodens use rear units which incorporate fog and reversing lights as well as reflectors and stop tail lamps. Mounting these on sturdy steel brackets rather than on the rear wings as before has also cut bulb failure. The reverse lights operate from a gear actuated switch.
To the front, the 11 in !lamps — very powerful difficult to set — have beer carded in favour of twin halogen units. These are E of Lucas or Cibie manufa and can be complemented btimber mounted oblong spot lamps. The headlight, also connected to the loor bayonet connectors.
Finally Fodens have m the batteries from beneatI cab on the nearside to a position on the chassis They are now enclosed steel box. Previously obstructed access to the pump and other ancillaries many operators felt there less likelihood of theft in original position.
The proof of the puddir of course, in the eating, Fodens say that since the i duction. of Truck-flex they had no burn-outs or other I lems. However, like all tt. that offer advantages, then cost penalty. The new systi between 10 and 15 per more expensive than the c replaces.
• by Steve C