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Old 13-09-2021, 03:41 PM
roughy (Mark)
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Motor for Roll Off Roof

Looking at automation for the backyard observatory as a summer project. First step will be an electric motor to open and close a roof. Seen a few options with a bit of research such as eBike motors (promising) and garage door motors (overpriced).

There are also some companies that make these items specifically for observatories but they too, are way overpriced.

The roof itself, including rolling resistance, would be less than 30kg.

Apart from the obvious functionality, it would also need to be capable of being controlled down the track by software such as Voyager or SGP.

Also, the observatory has 240v mains running to it.

Any advice most welcome.
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  #2  
Old 13-09-2021, 09:56 PM
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mswhin63 (Malcolm)
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You would need to calculate the Friction to overcome the initial work done. Once you have the initial resistance, that will be the power rating of the motor that you would need to look at.
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  #3  
Old 14-09-2021, 07:13 AM
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Go to Supacheap Auto or similar look at cheap 4wd winches..$200 on a good day, maybe less, pulls 2000 lbs but the big feature is you get all your cables, controls etc which saves you heaps.
I have two which pull a 3.8 x 3.8 mt roof ...needed two because actually makes cabling easier plus there was no way I could get a "drum" system to be reliable...it ended up slipping no matter what...so now they both pull on each corner..have to rewind and reset but the advantages are worth the extra mucking about...as I said think what is in your package...you get......the following:-
Winch, electrical cable to hand controller, power leads to battery ( or 240 to 12 vlt unit ..plus why not leave a battery in the system ..for heater or a light ..whatever) stainless steel cable to drag the roof ... its the cost of all the little things that get to you plus usually compromising on this or that...
Good luck and get started.
Alex
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Old 28-09-2021, 03:17 PM
Nico (John)
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Maybe a bit expensive $398 from Bunnings but a sliding gate motor works excellent on my obs. All you need to get is a box of toothed rail that is also available. On the inside of the control unit you can access the digital control signals for open/close. I've designed a cct that you could use to externally control via SGP (but not tested) but I find that using the remote control is just as easy.

John
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  #5  
Old 28-09-2021, 04:18 PM
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Merlin66 (Ken)
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Alternative...
A small geared motor and a length of bicycle chain. A couple of sprockets and the chain connected to the roof at both ends.
There are many amateur observatories using this system.
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  #6  
Old 29-09-2021, 05:18 AM
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I thought of this...cheap.

https://www.homeappliancesplus.com.a...I-tR454sQKuj1Y

Slex
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  #7  
Old 29-09-2021, 06:07 AM
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mura_gadi (Steve)
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Hello,

I'd get a weight test on the roof, rig up a cable line at the mounting points your going to use. Then use some weights to work out how much force you'll need to get the roof moving.

If your going to use chains(non-bike ones), watch the length and slack or its going to be very hard to keep the rig quite.



Steve

Last edited by mura_gadi; 29-09-2021 at 06:25 AM.
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  #8  
Old 29-09-2021, 07:21 AM
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The big disadvantage of my set up, which uses two 4wd winches is the noise...it is unbelievable and such that I asked my neighbour near half a klm away if it annoyed them..they said after they go to bed they hear nothing fortunately.
Alex
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  #9  
Old 29-09-2021, 04:11 PM
Nico (John)
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Bunnings - Gorrila 240v 100kg electric hoist. $130 bucks.
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  #10  
Old 01-10-2021, 01:49 PM
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pmrid (Peter)
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I used a 4WD recovery winch with some 3mm SS cable and pulleys. Steel-framed 5m x 5m roof. Ran on V-pulleys along some raised bar. Plenty of grease and worked a treat.
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