rumor has it that Peter wrote: > Series glow plugs are resistors, and there are six resistance loops > per engine (two resistance elements on the fours, one on the fives, > and I presume none on the six cylinder truck engines). > > There is a 1.3 V or so voltage drop across each resistance element, > total current is about 30 - 40 A at 12V DC. > > The voltage doesn't "go" anywhere. > > Parallel pluts are also resistors, but they have a resistance built > into the relay and are all wired direct.
You were doing fine until here. There is _no_ resistance built into the relay. Each parallel glow plug has a higher resistance than the series plug. Thus each one operates on 12V, not 2V. > Same principle (resistance > heating), just a different application. I believe the parallel > plugs get hotter, and they heat up much faster, as anyone with a > manual series GP car will attest. This is partly because all of the heat is in the pre-chamber rather than on the "toaster wires" between plugs. The result is that about 1/3 of the heat generated is wasted outside of the engine. Jim C. is convinced that if that "wasted" heat were put into the air intake there would be little difference between series and parallel plugs starting ability. I won't argue with him! *grin* -- Philip, who converted his series to parallel
