In my 30 plus years in the elevator craft, I have never seen or heard of any standard of L1 and L2, and I have worked on many DC motor starter/reverser panels. Different manufacturers used whatever designation they wanted to, every print I ever saw made it clear which input terminal was to be positive and which was negative. Polarity is very important, large contactors have "blowout" coils or magnets, improper polarity can prevent the arc formed when a contact opens from being snuffed. A flashover between contacts is a sensory experience you will not forget! It is great to hear someone discussing old control gear, learning about it is vital for proficiency with newer controls, and there is a surprising amount of that gear still in use today.
Bruce Gentry, KA2IVY International Union of Elevator Constructors, Local 62, Retired
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On 8/28/19 10:03 PM, Dave Seiter wrote:
On the schematics pertaining to DC shunt/series motor starters, is there any naming convention relating to L1 and L2 being positive/negative? I ask because I'm used to DC systems specifying polarity, and the only "polarity" mentioned on the schematic I have is the name "D.C. Automatic Starter".
I'm cross posting on Tekscopes2, where any discussion should take place, and adding more info there.
-Dave
