Home Forums General Discussion Technical Questions Otis CX circuit

I found C out on an old 70's UCL car a couple of times now. I had potential throughout the circuit but C wouldn't pick automatically. There's a CX relay in parallel towards the end of the circuit, on the HL1 side of the circuit. Is this some kind of CX lockout so a mechanic can come take a look at the car before C can pick back up? Or so it stops softly and/or won't try to run/stop on a flaky switch? The car was about 2' out of the bottom floor both times in the same spot.

It has been a while, but if memory serves me, this is the circuit that shuts down the C circuit if the car is still in High speed, FE relay up, when the car hits the emergency terminal slowdown switches. the only way to reset it is to turn off power, or recycle one of the safety devices in series with the C relay. Some how you are not getting a normal slowdown at the bottom floor, or your slowdown switches are flaky.

The only thing I remember about it is, when we would leave the machine room, we would pull C out, while holding CX in, creating a C/CX lockup. The car would sit at the floor docile, until we walked down the stairs, re-set the car stop switch, and then it would run on auto. It was neat way of holding the car while walking dwon two flights from the machine room.

Is this almost utterly worthless to you? I suspect so.

If I had a print, I'd try to make a more intelligent answer. Sorry.

I wasn't sure if the car was going up or down and I can just push in C and it will hold in. There are some directional back contacts around those slowdown switches, I'll check both.

Westinghouse DMR had an RS2 relay that we would do the same thing with to hold the car until we could get down from the machine room.

I guess the idea of it is, once some contact opens the C-circuit, it won't pick back up right away, but instead C will just drop out and stay out, (tell-tale CX then coming in), until the safety circuit has been cycled, and then C will pick back up, as has been said. Maybe to keep cars from starting, and stopping repeatedly, in case some issue exists, like maybe a broken tape switch bouncing open and closed. So they wanted to get the car to stop, and stay stopped, (C/CX lockup) until it has been checked out. Just guessing.

yep i think its a safety if a terminal stop is not right ie too fast or fe relay not working right. if fe n/c contact doesnt make then the juice wont go thru 1ls(going up) then c will drop out. cx is still in due to safties still ok but this is so c relay doesnt osolate and is definitive off or on. a reset of the safty cct will reset cx relay

Y'all were right on the money. I think it was FE 9/10 n.c. contact. It had moved outward and was barely touching the stationary contact because the shunt screw was a little loose. Thanks!

On the older controllers when you are not sure of direction of travel or even open/close on door relays just look at the walking beam behind the relays that keep both from coming in at one time and you will be able to tell the last relay that was picked!

That's a great tip!