On Sat, 26 Jul 2008 11:43:00 -0400 daestrom wrote: | Salmon Egg wrote: |> In article , |> "daestrom" wrote: |>
|>> Or interrupting an inductive load. This usually takes a more robust |>> contact design than simple resistive loads so they are rated for |>> less when controlling motors. |>
|> That was what I was pointing out. |>
| | Well, *you* mentioned 'starting requirements'. I was pointing out that is | the *interrupting* of inductive current that would be the issue, not the | initial closing.
I learned the hard way what current through an inductor wants to do when it is interrupted. Back in the 1960's I had a Heathkit experimentation board. It was powered by 4 C cell batteries (safe, eh?). I was playing with my own circuit wirings and wired up the little relay with the coil and the normally closed contacts in series. It became a little mechanical oscillator. One thing I noticed was that it was a higher frequency than the other way which was to wire the normally open contacts to short out the coil when closed. It also had a nice blue arc as the contact opened (that should have been a warning). Being curious, I touched the relay contact arm. Got a good jolt out of that. That was no 6 volts.