Countertalk: Knowledge Building: Understanding Alternator Output

In the world of heavy-duty equipment, applications can vary far more than in the standard light vehicle world.

Think about it: how many consumers specify the output of such components as starters and alternators? Or choose from a variety of manufacturers when deciding which engine to put under the hood?

Sure, the average car may be dressed up a little differently depending on personal preferences, but the variety of options is strictly limited.

When you start talking about trucks, however, the options are vast: this engine with that chassis, with these accessory drives, and that electrical system. The options are obviously not infinite, but not every truck is like every other. It depends who ordered it and how they wanted it, depending on specific local regulations, maintenance facilities, personal preferences and, yes, budgets.

Which means that when it comes to replacement time, it may not be as simple as reaching into a catalogue with make, model and year in hand.

At this point, it is useful to have an understanding of how different factors affect alternator selection, for example. Key among these is understanding how idle and pulley ratio affect alternator output. This involves a number of fairly simple, but critical, calculations.

Special thanks to Leece-Neville for information used in this article.