- May 2, 2015
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Hi gpop1
As I haven't bought the 0,6rpm motor yet, I will certainly take your advice. I presume the furtherest from the centre the motor is the less strain it will take and hence last longer. One of the challenges in building this unit is that it will be a long way away, so I am really going for tried and tested (and was thinking that I would build redundancy into it for stuff that fails). If it was here with me, I'd be testing how cheaply and efficiently I could build it, but I like tinkering. I had even thought that all I needed was a tiny aquarium pump, and two big tanks suspended from each side of the trays, and that by simply pumping water from one side to the other , the trays would tilt.
So on a 300mm shelf (12") a 40 degree either side tilt moves the shelf edges through 193mm (7,6") a 150 (6") travel will be 117mm from the centre, while the 100mm (4") is close to halfway at 78mm(3"). In this situation 6" (150mm) actuator, makes sense, unless I was to use wider than 12" shelves. The load on the actuator will be light, unless the eggs are really badly packed. I see a 150mm actuator is rated for 500Newtons so it should lift a mass of 50kg or 110 pounds (about 720 Jumbo eggs or 1000 medium eggs). so even if I went for 24" deep shelves it can handle it. I looked at the 0,6rpm motor, it has a torque of 25kg/cm so at our 78mm arm (ie 100mm travel) it can lift a mass of 320 grams (or 5 eggs ) If my calculation is right.
I had been wondering what the best way to heat it is.. I presume you are suggesting 100w Peltiers? What are the advantages of the Peltiers over the alternatives?
I once ran my home built telescope with a tiny motor, it always amazed me how such a small stepper could move something so big.
The real challenge is knowing whats easy for a motor, as thats really the sweet spot. How does one handle jams.. can it be programmed to stop or reverse if it hits an obstacle ? or does it just stop without damage?
I have kept chickens for about 8 years now, but have relied on skilful hens to hatch the necessary offspring, I am hoping this incubator can create a successful business. I am in South Africa, but this incubator is going to do service in a rural area in Malawi.
I could never work out the torque of the 0.6rpm motor as its listed as kg-cm. I know from personal experience that it can tear a aluminum 6mm flex coupler in half if you jam the tilt table.
I wouldn't see a problem turning 50-100 eggs with the 0.6 motor but when you start looking at 150 and more then you may need a larger motor. The trouble with tilt tables is that you need a motor that will not free wheel when it stops. Also how do you plan to hatch unless the turners can be removed?
In 12vdc you are limited to a few types of heaters. The ptc is the cheapest and you can get a 250w that can be unwired so you end up with 3 @ 83w that can be controlled independently. I like the peltier but it has its draw backs especially due to the aluminum heat sink which can make temperature control difficult. I do like the fact that the peltier can be reversed and the temperature can be brought down inside the incubator. Ive no idea if that would be a useful option. In a hot country when the incubator is not kept inside a climate controlled home I could see it being useful. My incubator about 14"x 24"x 18" internal uses one 72w peltier and that is constantly adjusting between 9 to 100% power (haven't ever bothered to work out the average power usage over 24hrs but it probably averages around 35w).