Alternators and Generators
This page covers a brief history of Chrysler and the alternator; alternators vs generators; and troubleshooting alternator problems.
A brief history of Chrysler and the alternator
Experimentation for automotive alternators began in earnest in 1949, from military applications during World War II. They had numerous advantages over the generators which came in every non-fleet car from the brass era to 1959:
- Alternators charge while the engine was idling, reducing battery use and allowing for more use of electric accessories (seats, windows, radios, etc.)
- Alternators can have a much longer lifespan because the brushes don’t handle their full power
- Alternators can create far more power than generators, in automotive use
On the down-side, early alternators used mechanical voltage regulators, resulting in pulsing at idle. That was eventually fixed by using electronic regulators.
Dodge started selling Leece-Neville alternators as options in their taxi and police cars as far back as 1950, and later had them as an option in Power Wagon. By 1957 (possibly earlier), Ford had optional alternators in police cars and ambulances.
Chrysler opened their own electrical parts plant (Electrical Equipment Division of the Automotive Manufacturing Group) in 1958, in Indianapolis, Indiana. The Electric Autolite Company of Toledo, Ohio had been Chrysler’s main ignition and electrical supplier since 1935. (Chrysler had an aluminum die casting operation at Kokomo, Indiana.) The Automotive Manufacturing Group also managed all the assembly, forge, foundry, engine, stamping, axle, transmission and parts plants in the U.S.; it had been formed in 1957, although the assembly plants outside of Detroit formed the Regional Car Assembly Group before then.
Glenn S. Farison was listed as the inventor on Chrysler’s patent number 3,184,625 on May 2, 1960. It covered an alternator rectifier unit which used diodes to convert the alternating current to direct current (AC to DC), and prevented the battery from turning the alternator into a motor when the alternator wasn't generating power. The invention allowed Chrysler to become the first automaker to include an alternator as standard equipment in their cars, starting in 1960. It “not only includes the structural assembly of the altenrator-rectifier but also the method of manufacture and assembly of certain of the novel alternator-rectifier components.” The patent application said,“The alternators heretofore supplied for commercial and special purpose passenger carrying motor vehicles have been expensive, large size, inefficient, noisy units...” Farison’s, by converting three-phase AC to DC through silicon diode rectifiers, operated at up to 60% of its capacity while at “the slowest engine idling speeds.” It eliminated the commutator, rotating armature, and current carrying arcs.
While Chrysler did not invent the alternator, they do appear to have been the first to use diodes to convert power, along with electronic voltage regulators, both presumably byproducts of their Defense Department research. Using electronic rectifiers (AC-DC converters) and voltage regulators eliminated periodic maintenance.
The use of the alternator on the Valiant went with its totally brand new image - new body, new unibody construction, new torsion bar suspension setup, new engine (slant six), new transmission (A904), new brakes (Bendix) and a new, standard, alternator.
Chrysler made their alternators at Indianapolis, Indiana. Chrysler would have used Essex Wire Corporation (Concord Avenue, Detroit) for electrical wire and components, their specialty, and possibly for assembly of some alternators, though Essex generally did not make generators or alternators, and Chrysler marketed the alternators as Chrysler-built. Essex had been founded in 1930; in 1964 they moved to Fort Wayne, Indiana, and in 1998 they were taken over by Superior Telecom (née Superior Cable) and became Superior Essex, which they remain today.
Leece-Neville continued to supply alternators of over 60 amps to Chrysler for years after 1960. Ford acquired two Autolite plants and limited rights to the Autolite name in 1961; Electric Autolite continued on as Prestolite, the name of one its subsidiaries. Leece-Neville Company, Cleveland, Ohio, was acquired by Prestolite; both names are still being manufactured by Prestolite Electric Corporation, Plymouth, Michigan. Ford lost Autolite (due to an anti-trust suit) in 1972, but continued to offer auto electric parts under the Motorcraft name. Autolite today is owned by
As a side note, Chrysler of Canada did not offer the alternator as standard equipment until 1963, even on the Valiant. Imported models came with the alternator, but not Canadian-built units. Chrysler of Canada purchased generators from Autolite Prestolite’s Sarnia (Ontario) factory; 60 amp generators were supplied by Bosch, while Leece-Neville alternators of 60 to 100 amps were still on the option list.
Mopar Action’s Rick Ehrenberg wrote:
Early units were rated at little as 30 ampere output ... okay for a dead-stock 1960 Valiant, sure, but a typical late-70s heated backlight draws that much current by itself. Add in a few kicker stereos, and the stocker is quickly overwhelmed. Of course, Mopar responded to the need for juice in several ways: ever-increasing current-output ratings, then a 1972 “squareback” redesign, then two entirely new alternators: a massive 100 amp (nominal, 117 max) unit in 1975, and a more compact, little-known in unit in 90 and 120 amp versions in 1987 and discontinued by 1989! After that date, all alternators in Mopars were “purchased.”
Begin with the 1972-up “squareback” unit; these are much more reliable than earlier versions due to the bolt-in diode block which eliminated all soldered connections. If your car is pre- 1970, use a stock, 1970-up style “flatpack” voltage regulator. (Swapping this into earlier cars is about a 20-minute job.)
Hemi Andersen noted that Chrysler’s last “internal” alternators were the compact, little-known unit shown above, made in 90 and 120 amp versions in 1987, and discontinued by 1989. He wrote, “Of all optional alternators, this is by far the finest design. I use only these alternators on my cars wherever possible. They are far better than the Nippon alternators and the Bosch alternators in that they can be repaired on the car: by taking off the black plastic cover on the back, you can replace the brush pack and the diodes. I have only replaced the brushes on one of my alternators in all these years.
Anyone who pays for a rebuilt alternator of this type could have fixed it for around $12 to $15 by replacing the brushes.”
Alternators vs generators
Generators use an armature (wire wound around and around) surrounded by a set of unmoving field coils, like a DC motor. The field coils are powered and the regulator controls current to the fields to control the output of the generator. As the armature turns, electrical current is induced in its windings.
One of the greatest advantages of generators was very clean electrical output, since they produced pure DC. However, all the current had to travel through the brushes and brush leads; this produced a lot of heat, and when the brushes would pass over the bars in the commutator, small electrical arcs would be produced, which shortened the life of the brush. To counter this, the brushes were made very hard, which wore out the commutator faster. Because all current traveled through the brushes, most generators had a maximum output of 50 amps.
Generators also needed a cut-out relay to disengage power to the generator when not charging. This was done so that the generator would not pick up power and turn into a motor, burning out when not being spun by the engine.
In alternators, the field coils are wound around a large bobbin and surrounded by two interlocking iron shells. The coil is attached to two copper slip rings; the regulator applies power to them through metal brushes to control charging. The whole rotating assembly is known as a rotor.
In the alternator, there is wire wound around a steel core, called the stator. The rotor spins inside of the stator. As the rotor spins, the alternating between north and south poles induces a current in the stator. The current is alternating current - hence the name “alternator.” The current from the stator passes through diodes - three or four positive diodes and three or four negative diodes, which polarize (or “rectify,” which is why the diode assembly is called a “rectifier”) the alternating current into direct current.
Alternators can produce much higher output than generators; current designs on produce over 160 amps. The brushes only carry current to power the rotor (about 7 amps, maximum), so they last far longer than generator brushes do. There are some disadvantages, though. The Lundell alternator requires two watts of power to spin for every one watt that it produces, making it relatively inefficient.
There are several new alternator designs out there - General Motors has gone to water-cooled alternators to keep the diodes cool on the newer model 4.6L Northstar V8s. Several companies now use combination a starter/alternator built into the engine's flywheel to allow for stop/start and hybrid systems.
Troubleshooting (from “Wizard”)
- Inside, the alternator generates AC voltages then diodes blocks one way and let power though in other way, that gives you some rippling DC but battery smooths this out also to regulate DC. Without battery or if either positive or negative hook ups on battery itself go bad, voltage rises, if total break, will go over 40volts. Pop pop pop! Goes the many electronic especially silicon chips stuff, blown bulbs.
- If alternator diode array, one of them shorts, you get whine in your radio speaker. Fix: replace diode array or rebuilt alternator of dubious quality. Check first becore trusting that businesses selling those rebuilds.
- In several years, well before 2010, car makers is putting in 36V system in next gen or two vehicles. (aka 42V).
- The ohm law and power laws favors efficient, smaller stuff, less losses with 36V. That was the same reason for moving to 12V from 6V system that is apt to have headlights glowing like binary brown dwarfs system especially electical wiring are bad to begin with.
- Diodes I find always shorted. Very rare it's open which is easy part, it's blown violently. BANG! or Crack.
- Pretwist wires and snip the sightly sorter of that heatsink compound. Tighten all the hold downs first before anybody leaves building in just case.