WHILE WE ARE ON THE SUBJECT OF BRUSHES...BUICK CARS OF THE LATE 1940’s AND EARLY 1950’s HAD AN INTERESTING SAFETY FEATURE.
1
They had what they called a “brush protected generator.” The “field” wire of the charging system was routed through the ignition system. When the brushes in the generator got too “short” from wear, the field wire would “ground out” the ignition and the car would not start. While this was a good idea in theory, it left a lot of early-day Buick owners stranded without warning (and very unhappy). The servicemen of the day carried a jumper wire in the tow truck. If this was the problem (a simple check), they used the jumper wire to bypass the generator to ignition circuit. If the car started, they simply drove it back to the dealership and installed new brushes in the generator. And the customer was happily on his way.
HEY, HOW COME THERE ARE SO MANY DIFFERENT SIZE PULLEYS USED ON THE SAME STYLE OF GENERATOR?
As we learned earlier, the pulley size is matched to the rpm at which the engine will spend most of its time running. In-town delivery trucks had a small diameter pulley so the armature turned faster at the low engine rpm, increasing the output at the slow speeds. MAKING ELECTRICITY All generators “make” electricity in much the same way. Let’s take a look and see what parts make up a generator and what job each of those parts has to perform. As I have done before, I will give you the official description of what a generator does, then explain things in common English. Generator operation is based on the principle of electromagnetic induction. This means that voltage is generated when any conductor is moved at right angles through a magnetic field. When voltage is produced in this manner, it will cause the current to flow in the conductor if that conductor is a complete circuit. Whew! Got all that? Now let’s explain that in common sense terms, starting with the internal parts. ARMATURE - An armature starts out as a bare hardened steel shaft. To this shaft is added a series or group of non-insulated copper wires wound close together. They in turn will form what is called a loop.

上一页下一页