Dover hydro circa 1964

Hello,
Maybe someone can give this a shot. Dover hydro, 3 stop. Freight Car.Runs top to bottom, until a door is opened to stop the car. No prints on the job. Two months ago i changed out the 2s2r relay and this corrected the problem. Relay is now faulty again and needs replacing. Any ideas why the short service life.?new component was installled same as the old.
Thanks.

magnetic switches in the hoistway?? Did a coil open? There are two versions of this lock-latch relay, 115vac and 230vac, which do you have?

Johnny,
Installed a 115v last time. Supplier said most common. Going to read voltage, see maybe it is the higher voltage relay that is required. Will post when solved. Thanks

This is a rotary right? You referring to the stepping relays?

Sounds like a continental or fleet wood?

Iggypop,
When you say 2r2s relay, do you mean the 2S and 2R relays?
On the fleet wood 2S & 2R relay are your second landing switches. And looking at my print I see they are 115vac. See if there is a data plate on the controller (E-#, drawing #s)?

There is a 2S relay, a 2R relay and a 2s-2r relay commonly called a lock-latch relay. Hoistway magnet switches may cause problems with the lock-latch not working correctly, but won't burn a coil open. Are coils going open? Is it always the same coil? Is your control voltage at 115VAC/230VAC or is it higher? Could it be a defective relay? Did it just go open or is it burnt(usually yellow but when burnt turns brown)?

when mechanical latching is involved, it could be a mechanical problem. This is why Otis used to put counters on their circuits, i mean after something like this operates like a million times, it's time to replace. OMMS