Wiring to control a lift

MisterBill2

Joined Jan 23, 2018
19,466
Hi All,
I am new to this forum.
I have retired from building and am in the process of building a lift in my home. I am using an electric hoist as the main lifting device.
I needed to replace the hand controller that it came with. I needed 3 control stations. I designed and built a 12/220 relay system that did this.
I am now ugrading this design to incorporate more safety features.
I want to close the 12v transformer when the lift is not in use. I have designed a capacitor in the circuit (see attached)
Will this work and how big a 12volt capacitor will I need.
The attachment in post#1 is not a circuit schematic diagram, it is a wiring diagram and thus it is rather difficult to see what the circuit is doing. Controlling a lift is actually fairly complex by the time all of the safety functions are included.
One final thought is that for a lift, a button must be held for any motion to happen. If it moves automaticly after a button is released, then it is an elevator. THat is a very big difference.
 

LowQCab

Joined Nov 6, 2012
4,311
All this is rather academic ...........
The Battery-Powered-Circuit I provided is super-simple,
and you can't force it do any thing wrong,
and it's CHEAP.
You already have the Push-Buttons in place,
now all You need to do is to throw all those expensive Relays into a Box in the Shed,
and replace them with one small Circuit-Board, and 4-Solid-State-Relays.
The only Power it uses is about the same as 2-small LED-Lights,
and only while the Motor is running.

I recommend using redundant Limit-Switches,
wired in Series for extra Safety,
if You only have single Limit-Switches, add 2 more.

Can You Solder Electronic Stuff ??
.
.
.
 

Thread Starter

Mantadive

Joined Jul 13, 2021
24
All this is rather academic ...........
The Battery-Powered-Circuit I provided is super-simple,
and you can't force it do any thing wrong,
and it's CHEAP.
You already have the Push-Buttons in place,
now all You need to do is to throw all those expensive Relays into a Box in the Shed,
and replace them with one small Circuit-Board, and 4-Solid-State-Relays.
The only Power it uses is about the same as 2-small LED-Lights,
and only while the Motor is running.

I recommend using redundant Limit-Switches,
wired in Series for extra Safety,
if You only have single Limit-Switches, add 2 more.

Can You Solder Electronic Stuff ??
.
.
.
[/
The attachment in post#1 is not a circuit schematic diagram, it is a wiring diagram and thus it is rather difficult to see what the circuit is doing. Controlling a lift is actually fairly complex by the time all of the safety functions are included.
One final thought is that for a lift, a button must be held for any motion to happen. If it moves automaticly after a button is released, then it is an elevator. THat is a very big difference.
Basically the circuit is operating 3 switching stations that operate 4 - 12/220 volt solid state relays. these relays emulate the hand held controller that came with the hoist motor. The hand held controller switch had a up button and a down button with 6 terminals and 4 wires that controlled the motor ( Obviously, the combination of wires changes the polarity going to the motor and thus the hoist goes up & down) The centre 2 terminals were power feeds.
The hoist is that - not a winch, meaning that it has a built in physical and electrical braking system.
The lift buttons have to be held down to work, that is basic safety. I have put in a lot of safety features, Micro switches underneath that stop the carriage, an internal door with a microswitch so that you have to have the door shut to operate, upper and lower limit switches, a solenoid operated catch that holds the lift in raised position until the down button is pressed. I have also incorporated a counterweight system on a seperate cable with an overspeed device that will stop the lift if the main cable fails. The net weight of the lift is 30 kg empty.
It also has emergency stop buttons at all control points.
The doors to the lift / lift well are self closing and heavy to open, a small child cannot open the doors.
Finally the interior of the lift well is painted RED with warning signs - DO NOT ENTER DANGEROUS MACHINERY.
I have put a lot of thought into this project. but like anything, is it idiot proof? I have tried hard.
 
Top