THE JUNIOR DYNAMO MOUNTED ON A LONG WOODEN BASE AND BELTED TO A GROOVED WHEEL FITTED WITH A CRANK SO THAT THE DYNAMO CAN BE RUN AT HIGH SPEED BY HAND POWER. THE ILLUSTRATION ALSO SHOWS A SMALL INCANDESCENT LAMP CONNECTED TO THE DYNAMO SO THAT WHEN THE CRANK IS TURNED THE LAMP WILL LIGHT.
It will be found that the dynamo will also operate as a very efficient little motor, but that on account of having a two-pole armature it must be started by giving the shaft a twist.
Fig. 262.—Complete Dynamo.
It can be used as a generator for lighting small lamps, electro-plating, etc., but cannot be used for recharging storage cells on account of having a two-pole armature.
The dynamo may be driven with a small water motor or from the driving-wheel of a sewing-machine.
Before the machine will generate as a dynamo, it must be connected to a battery and run as a motor. This will give the field the "residual magnetism" which is necessary before it can produce current itself.
