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I would have to disagree about the concept of field reversing. This is the scheme i implemented on my I-5 control design and it has worked fantastically. It is not only simple, but greatly reduces wiring. I will admit that the card setup proved problematic but i have sketched out some idea's on how to eliminate the cards while still retaining the safety features. Sketched is the operative word.. And you can connect MOV's in parallel :) Just my preference. > > It appears that you were victimized by the Field Reversing > > scheme that was in vogue during the E-12 S and the early E-15.Obviously > > an idea that was not well thought out, and poorly executed.Even a guy > > that fixed cars and trucks for a living could see that was a good one to > > repair, but not a good one to own. > > I have to agree. My first Elec-trak was an E20 and it's been pretty much > indestructible in terms of controller. The only problem was when one of > the field diodes failed, cost a few bucks to replace all four diodes on > card 4. And after 10 years of service I noticed the contactors for F > were getting warm, so I simply flipped the contactors over and now I can > run on the R ones for another 40 years or so. > > The E15 is more of a fickle thing, the concept of reversing the field > was cheaper to implement, but the result was a very annoying tendency to > blow out the relay if the MOV is bad and you go from F to R quickly. New > MOVs seem to make the problem go away but I'm guessing they blow up > eventually. > > Putting in E20 style reversing contactors would be the right way to go; > I might just do it. But I like the standard speeds, quick performance, > and simple reliability of the E20 system. > > Chris > |