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Shredder motor questions

Jean Goubert jeanbono

Shredder motor questions

20/02/2020 at 14:35

Hi there,
I’ve just received delivery of the shredder laserparts. Excited to get started with the build!
I’m looking for motors at the moment and I found this one on ebay
I’m not knowledgeable at all and I’m wondering what the “hollow bore” means.
Will I be able to put the hex shaft straight into there? (Once turned to the correct dimension?) Or do I need to find another shaft and some sort of coupler?
There is another motor with a 25mm hollow bore, is that preferable?
Thanks for your help!

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20/02/2020 at 17:30

the motor is alright but yet a little weak for thicker plastic.
the hollow bore means the inner diameter of the reducer, should be at 35mm for this type. so yes, you still need a coupling for this.
also, it´s good idea to operate this motor at 3phase, you still need and inverter to run it on mono phase.
does this make sense ?

20/02/2020 at 21:27

Hi g,
Thanks for your answer
Not sure I understand why I still need to run it on 3 phase + an inverter?
How do I fix the 35mm shaft in the hollow bore?
Would it not be better to get the one with the 25mm bore and then turn the Hex shaft to 25mm instead of 20mm and stick it straight in the gear box?

21/02/2020 at 21:22

inverter : will save you energy and gives you speed control and a number of safety electric functions. however, without you still need to install a start & run capacitor (large) on this very motor.

there is nothing you have to fix, ‘just’ get a drive shaft of 35mm diameter, with keyways and fitting couplings. 25ish mm driveshaft suggests a smaller type of motor too; even less likely to run well for this device.

I know this can be overwhelming and as always I recommend to find a metal work shop near you – for them it’s a piece of cake to get you the right parts, also for a better price.

21/02/2020 at 22:16

I think I understand. Any tips on the sort of inverter I need?
I thought the inverter was converting mono-phase to 3 phase so I could run a 3 phase motor in a workshop with only mono-phase.
Is there a different kind of inverter that goes from 3 phase to 1 phase?
Thanks for the shaft, that’s clear 😉

21/02/2020 at 22:30

we use this here since long in most machines (2.2kw just as the one). just make sure it takes 220V single phase, and outputs 3phase. You can also use a OmronM2X (350E) which has a over-load function to assist auto-reverse without  adding any sensor (rotary encoder disc). Both auto-revere ways are supported in the firmware. Having auto-reverse for this setup takes away the whole thing lot’s of hassle. Send me a DM if you need help – we have support channel on discord as well.

24/02/2020 at 10:17

185 Nm that is massive amount of torque.

24/02/2020 at 13:30

Is that a good thing then? Or should I look for something smaller?
Really struggling with the choice of motor..

25/02/2020 at 09:23

Just be carefull if you have only 1 cutter blade engaged and it locks up the cutter will explode. Form my design of shredder my blades can withstand about 400 lbf at the tip. You would put down 935 lbf. That is enough to blow up 2+ blades if they lock up. and i believe that precious plastics blade design is thinner than mine. Just saying make sure that your shredder can witstand those forces if it locks up or if you overload it.

25/02/2020 at 09:39

Just make sure that the motor stalls out before your shredder fails.

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