# Connection stepper motor directly or with pulleys and belts...?



## luky luke (Feb 9, 2013)

Hi,

Do you think it is better to connect the motors Nemas 34 5Nm live, or to pass through a gear ratio with pulleys and notched couroies if so which one?

My card is an Order of C11G in CNC4PC I also drivers and two power 40volts Geckos, by cons I do not know not much in electronics, if anyone among you wants to bring me a little help, it will not be refused, good evening to all, (in France it is 8:45 p.m.

Cordially, J-M


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## denny98501 (Feb 9, 2013)

luky luke said:


> Hi,
> 
> Do you think it is better to connect the motors Nemas 34 5Nm live, or to pass through a gear ratio with pulleys and notched couroies if so which one?
> 
> ...



Do your motors have enough torque without reduction?
You can multiply torque by 5 or so times with a set of cogs and a belt. 
Can your motors move the load fast enough with a belt drive, or do you need direct drive to get quicker speeds?
Direct drive will move the load faster than a reduction drive. 
Do you have any alignment issues?
Belt drive is a lot more tolerant to alignment issues than hooking a motor up directly to a shaft. 
Direct drive systems usually need some sort of alignment coupler to prevent binding. 
Do you have enough room to hang a direct drive motor on the end of your shaft or enough height to place a reduction system under the shaft. 

You have engineering decisions to make. 

Hope this helps, 
Dennis


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## DMS (Feb 10, 2013)

This was discussed a bit in the "Basic CNC" sticky [thread]8753[/thread], you may want to check that out for more details.

In general, I would say running stepper motors with no reduction is best. Stepper motors in general loose torque very quickly as RPM increases, so gearing things up a lot can reduce your speeds when traversing. It is of course going to depend on the size of your machine. with 345Nm, you may need to gear down to make things work on a larger machine, whereas they would work fine on a smaller machine.

Don't be intimidated by the electronics, they are fairly straightforward (unless you are trying to build your own motor drivers...). Mostly you connect power from your power supply to the drivers, and then connect 2 wires (1 step, 1 direction) from the breakout board to each of the drivers. The rest is just telling the software (Mach/LinuxCNC/some other software) what you connected where.


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## luky luke (Feb 10, 2013)

Hello and thank you for your answers,​
The motors sold at ArcEuroTrade, as I have already said, are 3.5 Nm in / / and 5Nm in series, I believes is put that the two axes X and Y in / / so 3.5 Nm, by cons I think the spindle connecting the axis Z of the spindle should be connected in series in 5Nm.​
- My milling machine really is not huge, it is a genus of BF20L (identical actually) which is already a suitable machine for my needs Machinist Steam; the spindle velocity is variable of course, but I do not see or connect the output "PWM" the schematic and of connection for the control card "CNC4PC" is not really very explicit on this subject, as you see my English is quite limited therefore...??​
- One last question: should the motor of "divisor" (fourth axis) to be as powerful as others I have a Nema 23, 2.5 Nm, do you think that would be enough.​
- Otherwise, I have two others mill, a small X2 and a big OT40FG but this is not into my current resources to undertake a reconvertion, since it would take of the servos motors and all the rest, is necessary to align dollars or pounds sterling !​
- For the moment I'll try to finish the milling machine correctly and then proceed the convertion of my Lathe of 650 mm HBM among spikes, I already invested this equipment, it remains for me that Encoder for screw threads at buy.​
- The "frequency variator is already installed (I already past 2 weeks, it is to tell you how I know nothing in electronic, my Job is the Machining but not Electro.​
- I enjoy your tips, thank you again.
   Good Day.
   Cordially, Jean-Michel.​


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## DMS (Feb 10, 2013)

I think those motors would be ok for either a BF20, or X2 machine. Lots of people gear down the Z axis, or use a larger motor because it tends to require more torque. Re-wiring to 5Nm may be all you need. Adding a gas strut to take the weight off the head also helps.

What are you using as your 4th axis? If you are converting a rotary table, the smaller motor should be fine, as those are usually geared down quite a bit (40:1 typically). Usually you don't need to move them too fast either, so rapids shouldn't be a problem.

The C11G looks like a nice board. I am running a simple C10 (2 actually), and they are of decent quality. I am currently working on getting my spindle connected to my controller (currently I turn it on manually), so I can't give much advice there unfortunately.


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## luky luke (Feb 11, 2013)

Hello DMS,
​I think of putting indeed only one jack at gas, but can I put 1 of them only, since the column is dovetail I do not think that poses problem, not installed side opposed to the plug of axis Z for example.​
​I indeed think of connecting my live Axis Z with Néma 34 in 5Nm (//) for the other 3,5Nm in series will be enough on X there, but via a flexible coupling like below, I hope to do it myself, for metal used I have what it is necessary, I will take of Aluminum: AU4G. But for the intermediate plastic part, would you have a suggestion to make me, I have “MACROLON”, it is a hard plastic, but will it break in the event of problems, moreover and it good the propriétées mechanical ones, or needs is machined a more elastic and tender plastic this one, that you think of all that?​
​To answer your question, my diviser chuck is made by Soba Ø160 horizontal or vertical, sufficient for what I do; and the engine will be Néma 23 of 2,5Nm; are my four Drivers Geckos microphone-not 50V/4,2A (SD5042) 

​
I visited the site that you have indicate to me: Lobo.com it is top for you, fills of super bonds like Mac Master, but too far for France, transport is almost more expensive than the product, damage that there is not in England, in any case it is full with good information, I have some to recover a maximum if one day I decide to make a Router. It is really not expensive, but one always returns from there to transport!!!
​Let us return to my Machine: it me remains that to connect Chart of Order C11G, (There I am given, if somebody among you has the same one, it would be possible to have a little assistance of his share), for the rest of the operations: engines; and construction of the desk, it is cool, I have full of sheets of casings PC Black, which I will machine, to cross then to fold, I have the intention incorporating the PC in Electrical power box with the cards, drivers, my 2 power-boxes 40V, and PC included., (not cable walkmen). ​
Good day Machinists, so long.​Cordially, Jean-Michel​


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## LoboCNC (Feb 11, 2013)

I'd go with a cogged belt drive for a couple of reasons:
1. You usually will need a flexible coupling between motor and drive screw or a direct connection.  Using a belt drive, which in effect gives you a flexible coupling, really isn't that much added hardware, and it makes it easier to add a hand-crank.
2. Until you get the whole thing hook up with drivers, you won't really know how your speed/torque balance will be.  It very well could be that your NEMA 34 motors will want to be geared up instead of geared down.  Adding the belt drive will give you the flexibility of changing the ratio as needed.


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## luky luke (Feb 15, 2013)

Hello lobocnc,​I already tested speed the engines without the assembled assets, but with Mach3 all is skeletal level speed, and then I also have Joystick to briefly test with the assembly.​When I bought my engines I have all took them with double outputs of axes, with the result that I can mount a crank on each axis, you do not think that it is a good idea, the problem it is that the BF20L is a small machine to add pulleys, I found the connection direct more compact and discreteI am sorry for my bad English, I hope to me you able me understand yourselves without too much problem, that of Google is still worse, it is of the Chinese!!!​cordially,​Jean-Michel​


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