(Almost) Definitive guide on Motors (WIP)
I’ve summarised a bit of the various posts on the motors that can be found around in this forum, and wrote this Google Doc that you can all see, comment and edit.
check it out and help complete it if you can / want.
The idea is to start preparing a simple, clean doc about the motors to expand the awesome specsheets that @davehakkens produced.
let’s keep the messy discussion here in the forum or as comments in the doc and there put only the final results.
It would be great to put some examples, with the pictures of the label of the working motors that people are using.
@davehakkens could you post a pic of yours or is it all painted in grey? 😉
If anyone here has made the machines and they are working, please post images of the nameplate of your motor and what the pros and cons you see in them
Let me know what you think
thanks to all
ps I’m in Malaga, Spain too if any other spaniard wants to hook up. We also found some providers we can talk about and if we order all together the pieces maybe we get a discount 😉
So I have a motor I could get, but I want to see what you guys think of the specs, link below to view it in my drive
From your specs sheets, it shows that it is a 442W motor. This is way too low power for the shredder. It may be enough for the extruder but I am not sure still.
Although I have not finished the machines yet, the motor I will be testing with are 1500W each, over 3 times more powerful than yours.
First off, very cool topic thanks a lot for the ones who really know about this stuff to help out. I wish I would have studied engineering now!
I am based in Czech getting things ready for shredder and hopefully others. About to purchase an engine with a gearbox so I thought that I get your opinion here.
The price is reasonable 150Euro for a used one but its a German Engine and seems to be in a very good condition. What is left, is to think about the specs so here it is.
HP: 2.2 kW *(triphase I will have someon rewire it so I will do calc with 70% power)
RPM: 47 (this bothers me a bit, as it will very slow, but then again I should not have any problems with shredding anything)
Torque (Nm) = Power (Watts) / (RMP * 0.105)
312.0 = 1540/(47*0.105)
Got to 312Nm so that seems to be more than enough. What do you think?
Attached a picture, the label is a bit hard to read.
i just got an offer for a motor with 1,5 kw and 80 rpm with at least 150 nm according to my calculation, for 135 euros. What do you think about that? I live in Germany btw. Motors are not very rare on our market, but i think one with 80 rpm is.
Sounds like a fair price to me man, based on the Czech market so go for it!
Hi all! I’m making the extruder and I have this motor. I am also trying to have the machine’s power source be from the standard U.S.A. outlet voltage of 120 V.
Looking for feedback on how I would adapt this motor to work for the extruder and if I could make it run on 120 V.
This is the Torque of some mono phase electric motors respect to the Power and RPM, as you can see, you can have the same torque from a 550 w motor @ 17RPM respect to a 2200w motor @70 RPM. We must think that electricity is expensive and produce it is not always green.
Can someone please post what horsepower motor (or kwh) Dave is using for his new upgraded extruder with the professional screw ?
Thanks for the info, I have already ordered a new inverter duty” 1.12 KW motor with 2 HP PWM Drive (analog style):
Also 1.5 HP gearbox 20:1
Thinking now of returning motor and gearbox for 2HP rated models.
Hey all, so I checked the linked Gdrive and the link to the wiki http://www.preciousplasticwiki.com website prompts this message “This domain has recently been listed in the marketplace. Please click here to inquire.”
Is the info backedup? Shouldn’t the website be re acquired? new web adress?
we neeed a wikiiiiii 😉
@xxxolivierxxx All good; indeed PP has been going on the long run, people jumping in & out of projects..
Most of the french community is willing to relaunch a wiki system. Could we reinitiate the wiki process ? Though the work to link the intel from forum is INSANE, once it’ll be uptodate it’ll be quite “smooth” to add future info ?
i’ll create a new post w/ a poll link to see how the PP community feels about it
I’m machine builder here in Catalonia and I’ve got lots of shredder build requests in the last weeks and I’m also looking for a cheaper solution about the motor. Since I’ve completed now my machine shop (CNC/Milling table, a large CNC lathe, strong 4th axis) I am now open for experiments to tackle the motor problem for the future. So if anyone has idea but no machines to build it, let me know, I am there to help.
My recent idea about all this is :
– use a large wheel with at least 1.30 diameter for the transmission between the motor and the shredder
– the wheel has enough surface on the outer diameter to create enough friction so that you can put a motor right next to it with larger shaft, rubbing on the wheel
– also not tested yet: eventually we use a belt to connect the motor to the wheel
I hope that this way would allow weaker motors from scrap yards but I never tested this…. Did someone tried this already ?
@imuh Sure, sounds like a great idea, as long as it’s properly maintained and updated as often as possible. Maybe @robksawyer can give you a copy of his wiki database or transfer you the domain name so that you dont have to start from scratch.
@greenbean18 No my friend, the torque of that motor is only 97N.m, you need as least 300N.m to shred plastic without jamming
How do I solve for N.m?
I sent you a response through PM already but let me repost it here:
Use this tool to calculate torque, it will make your life easier:http://www.wentec.com/unipower/calculators/power_torque.asp
As an example, let’s enter the details of your motor:
Power in HP = 2
Speed: We dont know yet
We know that the motor has 1441rpm according to the information on your link, but we need to know the RPMs after reduction not before.
There are many different reducers with different reduction ratios: 1:20, 1:30, 1:40, 1:50, etc… the bigger the number, the bigger the reduction is (less resultant RPMs) and the stronger your motor will be (less RPMS = more torque)
lets use for example a 1:30 reducer, which means that for every 30 rotations of your motor, the reducer will rotate only once. If we take 1441/30 = 48.03rpms so lets enter that in the torque calculator.
Power in HP = 2
Resultant torque in N.m = 296.50
That’s not bad but we are aiming for 300N.m or more, so lets try a bigger reduction ratio like 1:401441/40 = 36, not lets enter that into the calculator:
Power in HP = 2
Resultant torque in N.m = 395.59
395.59N.m is perfect, which means that for that motor you found, you need a gearbox with a reduction factor greater than 1:30
Hope that was clear
Just curious does anyone have any experience with motors for the extruder?
I originally bought a 0.55kw 2800 rpm motor and planned on using a custom 40:1 or 50:1 reduction worm gearbox to bring it down to the right speed and torque but that was a long time ago and I’ve since seen you guys seem to be struggling with anything sub 100 Nm.
So yeah, wondering what sort of Torque you guys were using on an extruder if something as low as 7 Nm would work like this, or whether I’m better off using my big motor as above.
@jetaylor97 that motor you posted has more than enough torque for the extruder (not for making beams though) however, 80 rpms is too much. In the extruder, you need to have ideally less than 40RPM, or a variable speed controller if possible.
I made a small extruder with a windshield wiper motor, a 24v power supply, a PWM to regular the RPMs of the motor, and it works perfectly, doesn’t have a lot of torque but its more than enough for extruding
Hey @xxxolivierxxx thanks for the reply, ideally I do want to go all in on the extruder with beams being the goal. Do you know what sort of torque I’d be looking at for the beam extruder / compression screw?
Tempted to just buy that motor and do a further 2:1 reduction to half the RPM down to 40 and double the torque. (Oddly using this calculator 0.13kw / 40 RPM gets me 31 Nm which is more like 4x the current torque. Is that just theoretical torque and you lose some during the reduction or?)
Thanks again 🙂
@jetaylor97 the calculator seems to be fine:
0.13kw + 80rpm = 15.52N.m
0.13kw + 40rpm = 31.03N.m
I think Dave was using a 1kw motor with his beams extruder working at around 300N.m, @davehakkens correct me if I’m wrong
And finally, yes. All gear reduction mechanisms have some efficiency rating and they are never 100% efficient, which means they will lose a percentage of torque during the reduction process.
I managed to get a handle on two used three phase geared motors one with L drive, will need some advice on how to convert it to single phase.
Looking at the specifications hope this will do the job
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