The Lost Art of Rebuilding Generators Powerhouse Generator Part V COLUMN BY BOB THOMAS When the first Model A Ford came off the assembly line on October 20, 1927, the “New Ford Car” was full of innova- tions, just as the company had promised. Among them was a standard equipment electrical sys- tem complete with a unique generator. Designed after the commercial genera- tors of the time, the unit quickly became known as the “Powerhouse Generator” in part because of the whopping 22 amps it was capable of producing. This generator, like most Ford parts, was manufactured in house. The innovative generator utilized five brushes, six field coils, and an armature that was mounted to a tapered shaft by a bolt through the commutator. (Figure 1 shows a breakdown of parts) The shaft, which rides on two ball bearings, is installed through the closed drive end of the case, which looks more like a brake drum than a generator. The armature is then bolted to the tapered end, which protrudes into the open backside of the case. The brusholder mounts over the commutator. A cover, to keep out dust and contaminants, closes the open com- mutator end and is held in place by a spring clip. It is my guess that this cover, obvi- ously there to ease adjustment of the field brush for day or night driving, was at least partly responsible for the poor reputation for reliability that the Powerhouse later received. Even with all the lights on, the electrical demand was only about 10 amps. However, any driver who mistakenly believed that more amps was better could get them, until the armature burned up. In October of 1928, the number of brushes on the Powerhouse was reduced to three, probably to save money and lower output capability. At the same time, a new style “long-type” generator was also introduced on some models. In July of 1929, the Powerhouse was dis- continued for good, and replaced by a more conventional generator. Unlike the Powerhouse, it was manufactured by an outside vendor and saved the company money. Most of the 4.3 million Model A cars and trucks built between late 1927 and the end of 1931, came with the more familiar long generator. In addi- tion, many of the earlier Model A’s were converted by owners to the “long type”, because they were cheaper and consid- ered more reliable. For those reasons, Powerhouse gen- erators do not find their way into our rebuild shops very often. And when they do, we may find ourselves intimi- dated by them. What follows is a short description of the disassembly, and some tips on checking the parts and adjusting output. Removing the spring clip and cover is easy enough, as is the removal of the brusholder, which is held on by three screws. At this point you’ll see the nut on the end of the commutator (Fig 2). Loosen it (standard clock wise threads), but do not remove it. Grab the pulley with one hand and the armature with the other, and twist in opposite directions. You may have to gently tap on the head of the bolt to break the tapered shaft from the inside of the commutator. Then, you can remove the bolt and the armature will come out (Fig. 3). After removal of the pulley, which is held on the tapered drive end of the shaft in the same manner, you can get to the screw-on bearing retaining ring. Turn this ring counter-clockwise to remove it, and the shaft with both bearings can be gently forced out the drive end of the case (fig 4). The field coils are removed by taking out the two screws on each of the six pole shoes. Total amperage reading for the series of six coils should be about 1.6 amps at 6 volts, or 3.2 using 12 volts. Using the milliohm meter sold by Vensel Enterprises, I got a reading of .5 ohm on each individual coil, which told me they were balanced. Inspection of the insulation by removing the wrap proved them to be excellent condition. The armature had been overheated, and required rewinding. I sent it off to Holcombe Armature in Villa Rica, Georgia, along with the shaft, which I knew would be needed to turn the com- mutator. They did a great job. Upon inspection of the brusholder, I saw that the field brush had been in the maxi- mum output position, which explained what killed the armature. The original open bearings were easily removed from the shaft. Unlike many other generators that used oil lubrication on ball bearings, the Powerhouse bearings were packed with a liberal amount of grease. Slingers and cork seals helped keep it inside the gen- erator. The DE bearing was a 6204, and the CE bearing was a 6203. I replaced them with sealed bearings, and removed what remained of the cork seals. The slingers were in good shape and I replaced them for cosmetic purposes (fig 5). Always check with restoration cus- tomers before painting a unit. Some Powerhouse generators were black, and others were cadmium plated. This one needed to be black with cadmium plated back cover and the owner took care of the plating. The brusholder has two insulated brushes connected by a strap, two grou