Illustrated on page 7.
Ammeter (5). This is fitted into the top of the headlamp cowl near the switch. The instrument indicates whether electric current is entering the battery from the dynamo (charge) or whether current is being taken from the battery for lights, &c. (discharge). When the switch is in positions "OFF" or "CH." and the engine stationary, the needle should be at zero in the centre of the scale.
If the lights are switched on (either "H" or "L" position) and the engine is stationary the needle should move over to the left or "discharge" side, the distance that it moves depending upon how many, and which bulbs are alight. The discharge in "L" position will be nearly 2 amperes. (Two 6-volt bulbs taking 1 amp. and .5 amps. respectively plus the speedometer bulb .3 ampere). Note specially that if in the above circumstances the needle moves over to the " charge " side this is an indication that the battery has been connected up incorrectly, and the wiring must be put right before the engine is started. See page 69.
When the engine is started and the dynamo working the ammeter needle should indicate a "charge" reading if no lights are in use, and if the battery is in a fully charged state the reading will usually be about one to two amperes at normal running speeds.
On switching on the lights the needle will probably swing over to the "discharge" side for a little while, but if the engine is speeded up the automatic voltage regulator will step-up the dynamo output to compensate for the discharge and in normal night running at speeds of about thirty miles per hour and over in top gear, or at correspondingly lower speeds in the indirect gears, a small charge is usually shown or the needle remains at zero.
Speedometer (4). Fitted to the headlamp cowl. The needle indicates the road speed, and the figures show the total distance run. Speedometers are calibrated in Miles or Kilometres according to the requirements of the country in which the machine is used.