OK, this is overkill, but wanted to do this for some time

[Bill Dufour]

They add limit switches to electric actuators. They have one at each end. It goes to the limit and stops but it can reverse. I bet they are two way switches?
I meant the limit switches to control the light on/off. possibly a rope switch
Bil lD

[Jerry Bruette]

The problem is that the ceiling is 15-1/2 feet off the floor to get to the lights. Not going up a ladder to do that, and very costly to have my electrician do it. The motion sensing, battery lights actually work quite well under the shelf.

But I think the safety issue is really preventing the hoist from raising, or lowering the shelf too far. I'd love some way to install limit switches that would stop the hoist at the limits, but still have it powered so I can reverse direction and use it after the switch activates. Really want a way to do this.

The addition of a door light outside the entry door to warn people to not open the door widely when the shelf is down is just a nicety. At worst the door would hit the shelf and put a dent/scratch in the door. Not much of a safety hazard, just a nicety.

Alan, I think you can wire in some limit switches to stop the hoist wherever you want, and turn on your warning light.

I think all you'd need is a junction box with some terminal strips, a couple limit switches and some extra wire. You need to put the limit switches in the proper place in the circuit. That would be between the pendant and the hoist motor.

This should give you power to both switches in the pendant out to the j-box then to the NC limit switches. When either limit switch is tripped to the open position, stopping the hoist, the other pendant switch still has power to go in the other direction.

You could wire the warning light into the down half of the circuit.

Where I used to work we had numerous setups like this. Most of the time a PLC was involved, but that was to control several functions on several machine components and most of those components were 3 phase.

[Alan Lightstone]

That sounds very interesting, Jerry. I hate to get into the pendant cable, as it's reach is somewhat limited and the cable has to go up to the ceiling, which is too high to access now. But that sounds like a way to not stop the hoist from changing direction when it reaches its limit.

Much easier to get into the AC power cord before it gets to the outlet with a bypass push-button switch, but that isn't as idiot proof as the method you're suggesting.

[Wes Grass]

I worked out how to do this on 'something' some years back. Lever switches with a cam plate running past them, or a momentary pushbutton ... which I think was near impossible to find?

Wiring is lost somewhere in my head, maybe. Or a tattered notebook somewhere.

[Ron Selzer]

Alan
Do you really need limit switches to stop up and down travel or just one limit switch to turn warning light on when the lift is too low?
Set limit switch to kill power to warning light when lift raises up 6" past top of door.
Ron


clamp/screw wood,? to cable to trip the existing up limit, drop the shelf down and shorten the cable to set bottom limit

[Alan Lightstone]

I worked out how to do this on 'something' some years back. Lever switches with a cam plate running past them, or a momentary pushbutton ... which I think was near impossible to find?

Wiring is lost somewhere in my head, maybe. Or a tattered notebook somewhere.

No, I think for safety reasons I really need to kill power to the overhead hoist. There are nails driven into the wall next to the track that should physically prevent downward movement, but with a heavy enough shelf and contents, they may be overwhelmed.

On upwards travel, if the shelf goes off the top of the track, it could potentially tip forwards or backwards dropping heavy contents 6-8 feet from the air onto someone. Again a safety issue.

I picked up a pair of adjustable rotary level limit switches from Amazon. https://www.amazon.com/dp/B01HHN1LBY...roduct_details
Should be able to handle the AC load from the hoist. I'll need to have a bypass switch installed also if I take this route.

For now, trying AC control first, although may change to DC with a relay (more complicated. ? Safer, but really probably just a wash)

[Ron Selzer]

Allan
I understand your safety concerns, which are covered if you clamp something on the cable to engage the existing limit built into the hoist you will stop the upward motion. If you cut the cable to the proper needed length the shelf cannot come down any farther. Both are simple things that can be done from the ground without hiring anyone.
Ron

[Alan Lightstone]

Allan
I understand your safety concerns, which are covered if you clamp something on the cable to engage the existing limit built into the hoist you will stop the upward motion. If you cut the cable to the proper needed length the shelf cannot come down any farther. Both are simple things that can be done from the ground without hiring anyone.
Ron

Really, simple, sensible suggestions, Ron. Wish I had thought of those before installing the shelf. With the very tall ceilings, and depth of the shelf, I don't think I can get to the cable high enough up to make the upwards stop work. But really good suggestion.

As far as the bottom limit, I really can't take the shelf off now to cut the cable, even though that's a great idea too.

Oh well, I think back to the electronics drawing board with the two limit switches. The biggest difficulty now seems to be drilling through the wood supports for the linear rails to run the electrical cables through. Not insurmountable, but need a right angle hole drilled through the 1x6 wood supports.

[Alan Lightstone]

So I took some of the excellent advice above, and installed a rotary limit switch on the bottom of the run, with a wired momentary override switch to give power back to the overhead hoist when it reaches the lower limit. The wiring was a bit of a pain, but it seems to work great.

Now adding the limit switch to the top is much harder due to its height. Have to see about that one. I'm also thinking that it needs to be wired in series with the lower limit switch - so both are NC, but when one triggers the power gets cut off - as only one will trigger at a time.

As far as the light outside the door to show that the shelf is down -- still pondering that one.

[Alan Lightstone]

OK. Now have the rotary limit switch on the top of the run too. Both seem to work flawlessly, as does the override switch. Not the most elegant of installations, but seems to work perfectly.

I still haven't found a great solution to a wireless LED light outside the entry door for the workshop that would signal others that the shelf is down, and the door will hit it. I can power the inside portion of it, but it really would be easier if it had rechargeable batteries on both the signaling module (whatever that is, telling the receiving module that the light beam is broken, or the LIDAR senses an object, or an ultrasonic or photoelectric beam is broken) and a light turns on.

[George Yetka]

https://www.youtube.com/watch?v=ICX5S9lsNpI

Alan

In this video towards the end (around 19:40)he wires limit stops. He doesnt provide a diagram though

[Alan Lightstone]

https://www.youtube.com/watch?v=ICX5S9lsNpI

Alan

In this video towards the end (around 19:40)he wires limit stops. He doesnt provide a diagram though

Wow. And I thought what I was doing was overkill. Amazing, and quite elegant. But tremendous overkill.

[George Yetka]

Wow. And I thought what I was doing was overkill. Amazing, and quite elegant. But tremendous overkill.

I think thats this guys thing.

[Bill Dufour]

Why does this warning light have to be wireless? An electric eye type switch seems easy enough to adapt. Even a solar powered light that the sensor head goes into a can when the door comes down.
Bill D

[Alan Lightstone]

Why does this warning light have to be wireless? An electric eye type switch seems easy enough to adapt. Even a solar powered light that the sensor head goes into a can when the door comes down.
Bill D

Because getting wires around the double inside door under the shelf, and through the wall would be pretty unsightly. And there's no power outside the door.

I could get power to an electric eye on the inside. It's getting the signal to the outside and powering the outside light that's the issue.