Ok lets start off with the build list / bom for my light lifting machine of DOOM. Will it work? I say YES. Why? because I want it to. Time will tell however as I built all this in my head the other night haha. With some power shopping, you can probably build something like this for cheaper than I.
- Motor... One kick butt high torque window / wiper motor from robot market place! I choose a butt kicking window motor for the torque and metal gear box. Also motors like this have extreme holding power when off which means it will not go in reverse from the weight and let the light lower. Picture trying to pull down a car window.. yeah does not happen unless your car really sucks
Robot MarketPlace - AME 218-series 12V 212 in-lb LH gearmotor - stubby shaft
Next up! I need GEARS. I am going with a 15 tooth sprocket for #25 chain which will be drilled out and placed onto the kick butt window motor. I chose a 3/8 bore sprocket, however the wiper motor shaft is larger. Will get to drill out the sprocket for it to fit the motor shaft
Robot MarketPlace - Sprockets
Now the 15 tooth sprocket on the motor will be driving a 30 tooth sprocket with 5/8 keyed bore also located at this link... This will reduce the speed of the pulley shaft by 1/2. Not going to bother to get into the fancy numbers but the basics are the 116 peak rpm motor will be reduced down to around 58rpm at the pulleys.
That 30 tooth sprocket is going to attach to this 36" steel keyed shaft which will hold the pulleys that will draw the cables up which will be attached to the light, thus lifting it in all of its LED glory!....
5/8" X 36" Keyed Shaft
The shaft itself is going to be supported by these pillow bearings.... I plan for the whole motor assembly to be mounted in the attic, so all you will see is the cables coming out of the drywall. You could however mount this thing upside down and hang it from the roof like some other builds have their lifters.. However not... what I want to do.
5/8" High Centerheight Pillow Block Bearing UCPH202-10
Now you sort of get how this is going to work.... maybe. Next up, how I am going to make CHEAP pulleys for each cable! Each side of each cable pulley "2 in total" will be one of these shaft collars...
Robot MarketPlace - Shaft Collars
On the inside of each shaft collar will be a frame washer which will act as the sides of the pulley guides "pics soon to come" So the 5/8" shaft will end up being the pulley with the collars and washers attached! Since the shaft is 5/8", that makes for around 2" circumference. With the shaft turning at a max of around 60rpm, it will give a max lift of around 120 inches per minute "yes I rounded the numbers"
Now, since I like complicating things a little, I wanted very, very smooth lift and lowering ability. So instead of an On / Off switch to raise and lower the unit, I incorporated a bi-directional speed control so the actual rate of lift will depend on how far I crank the knob. This will make lift and lowering glass smooth... in theory The speed control I chose is located here... You will see it is only rated for 5amp, but the mods I do later should give it the ability to handle over 49a for very short periods of time. I do not expect anything close to this however. And of course there will be an on/off safety switch.
Bidirectional DC Motor Speed Controller Electronic Kit
Now, how do I power this thing? I need to send 12VDC to the speed control so I need a cheap power supply capable supplying a decent amount of current. So I found this cheap unit on the ebay machine rated at 30a
12V 30A 350W Regulated Switching Power Supply For CCTV - eBay (item 170595276354 end time Feb-24-11 17:37:21 PST)
Now, you technical heads may be getting the picture if the evil machine that I plan to build to raise my large and rather heavy light assembly.