PROTECTION OF GENERATOR

Shannon News, 30 November 1928, Page 4

PROTECTION OF GENERATOR

When a battery is removed from the car while the car is in .use, care has to be taken to prevent the generator bring burnt out. The ordinary automobile type generator already hass one brush grounded. When the insulated terminal which is connected to the insulated brush is grounded both sides of the armature are grounded; When the machine starts up it, will generate a slight voltage, which will send a small current through 1 the wire for* the ground connection. Except for the slight voltage needed to send the cur : rent through this wire, the two brushes are at the same potential or voltage. This means there is hardly any voltage difference developed in the ma ; dune, and accordingly there is practically no voltage available to send current through the shunt winding. Accordingly the machine continues to send a very small current through the short circuit connection, and never builds up any appreciable voltage, and never lias enough current in the shunt winding-to , amount to anything. On the other hand, if operated without any connection it builds up an abnormal voltage, and sends all of its current through the shunt winding, causing it to overheat in a very short, time. If operated very long this way the short circuit current usually demagnetises the machine. , After the battery is put back in the ear the generator can bo reuutgnctisod together with pliers or screwdriver. This energises the generator fields with battery current.