Hey, @plasticona yea i also think the winch would do but im not sure about the strength of the motor is enough.
In case of the axe, @plasticona and @enviro i found only one place until now that you send the bluprint or the 3d model and they send you the piece, the web page is this one http://www.protoandgo.com, I think they are in Barcelona but for me is expensive.
@enviro the 27 mm I found a company here in Madrid with those specification, but they sell only 3mts bar and to companies not to particulars, im trying to find something cheaper.
Hi @andresfabertime the hex bar can be hard to find, I have found that out my self, in Australia it is not something standard to be found at metal merchants & when you do find someone who will get it for you, they want to sell you 3m of it, also the size here, 27mm is also not common.
So this is what I am doing.
The 2 hex bar sizes in my country that are more common are 28.5mm & 25.4mm, it just so happens that crowbars (that’s what there called here) are 25.4mm & you can find them at scrap metal yards easy. Here is a photo of one.
Note: you will need to change the CAD file to allowed for the different hex size.
@andresfabertime i was also thinking about using an old car winch, that should work, but it’s just my guess. By the way, i’m in Portugal and i’m having some troubles finding the hexagonal bar. Do you found it easy?
No, your maths is correct. 270Nm is what a 2kW 70rpm motor would produce, but it’s probably way in excess of what the shredder actually needs, and possibly also more than the gearbox can cope with, so if you were to lock the shaft it may destroy itself.
Nobody has yet posted any measurements but I’d estimate the shredder only needs 50-100Nm to chew through most things. This gives you more flexibility in motor choice, most important is the torque, then the speed, less than 70rpm is probably fine, it will just go slower, too fast and material will get thrown out instead of shredded. The torque x the speed tells you the power of the motor you need to look for.
Hi, I found a old Car winch with the specifications of 1000 W and 600 kg and another with 900W/ 1.2Hp Motor, they are 12v but i was thinking of using a converter from 220v to 12v.
Do you think something like this could work? or i need more power for the shedder?
In my opinion the best motor for this applications is the classic asyncronous 3ph motor. With capacitor properly connected you can run it with 1ph power supply no needing inverter or any other devilry.
The price of 2Kw brand new motor without gearbox starts from 150Euro, but this kind of motor is quite easy to find used in scrapyard or ebay at low price, often with gearbox mounted.
Changing form 3ph to 1ph adding capacitor, the motor loses a lot of its starting torque, but in shredder application it’s enough start the motor with no plastic inside the hopper.
yes, those winches look good, i’m just worried about the current they draw. Some of them can go up to 150A which is no problem for a car battery for short periods of time, but i think for longer times you would need a power supply which then becomes very expensive again for that current rating. I think.
I dont know the specs of those hoists yet, they just say how many kg they can lift. The 1700w hoist can lift 500kg straight. Anyone know how many NM that would be?
I think you may run into problems with the Ebay one(DAYTON AC Gearmotor 70 rpm). The RPMs are fine, but the torque may not be enough. With @enviro s links I calculated Dave Hakkens’s 2kw motor at 70rpm to have 272Nm. Could that be correct?
Another Idea I just thought of:- concrete mixer motors. The ones that don’t use pulleys all have a gear system attached. Not sure of the speeds though, 20rpm may be too slow, what do you guys think?
The winch motor looks like it would work extremely well. Do you know the torque for one of those @paulfreed? It made me think of winch motors. Lots here on craigslist.
I’ve also thought about the drill press, but id like to avoid the cumbersome pulleys. Although its probably alot cheaper than the worm gear.
I’ve been thinking of winch and hoist motors – they have plenty of power. What do you guys think?
The winches are normally 12v used on pickups etc., but would then need additional expensive power supplies.
The hoists I favor because they have a gear on them and are 1ph. Also the gear comes directly off the motor shaft unlike most winches. I think the ones you get here are up to 1700W, just need t find a second hand one…
Perfect. Thanks @enviro . I have been looking at all sorts of used kitchen equipment for matches. I am not an electrician either. Going to keep a list of options and the. Through a few on with stats soon.
Hey Guys, I to am looking at alternative motors as-well, as the one thats recommended is not easy to find in a lot of countries.
I should say these are just some of my thoughts, as I any not a electrician, but I did have a really good talk to a mate of mine who is.
First, as already mentioned by @paulfreed over here
most households are on 1ph power not 3hp, you can run a 3ph motor at home, but you would need to use a type of inverter. The other thing that I’m finding is most of the motors that are easy to find the RPM start at 1400rpm & goes up from there.
Solutions.
I myself am trying to keep things simple & in turn that should keep the cost down, hehehe
So! for me I’m looking at as a alternative, is 1ph motors with as low as rpm as I can get & using in conjunction with some type gearbox/worm gearbox, so I end up with the rpm/torque that I want.
What & Places I’m look at.
Ebay, Gumtree, 2nd hand places, kerbside pickups.
1. 2nd hand drill press, some are 1400 rpm & 12 speed they uses belts & pulleys to change the rpm, (which could be repurposed to use in your design)
2. Washing machine motor
There is also the 12v & 24v options as well that I’m looking into.
I’ll share what I come across as I find it & hope others do the same.
Also, if any one know of a good online calculator that easily works out the gear ratio you need when you want to reduce the rpm of the motor you have available, to the rpm you want. That would be awesome & very helpfully all like me that are maths deficient.
