It is easy:
EQ6 has 180 teeth worm, so 16*180 = 2880.
No, you cant use conventional or V belts, because their reduction ratio will depend on pulley's diameters.. and there will be also some un-controlled amount of slippage in such pulley-belt system, so you have to use timing belt and pulleys.
Planetary gearboxes from tools are good idea, however the backlash will definitely be there - those gearboxes are not designed with precision in mind.
All depends of what you want to do:
- If you are using Bartels' system, reduction ratio is not critical (because it is parameter, entered into config.dat file).
- If you want to use existing driving circuit, then you must maintain the existing reduction ratio (because you can't change that parameter in existing synscan and so on units.. The exception here is Darren's mod, which I am using and it accepts wide range of reduction ratios.
Give me some more details of the design (what motor, how many steps and so on) so that I can be more specific.
But, one thing is certain: the simpler, the better.
That means, 200-step motor (with micro-stepping) driving timing pulley reduction 1:4 (this one can be fitted inside EQ6) or 1:8, which is then coupled to EQ6 worm-gear.. Bartels' program does that easily (but requires DOS on PC, 33MHz old laptop works OK.. faster the better of course).
If you have just a stepper driver, and need specific frequency to drive it, you have to calculate what it should be (based on available reduction) this can be generated by micro controller easily.. and here you go..
Now, you've got me thinking about V-belts... if you have auto-guider, actually, in principle, you CAN use v-belts.. because the guider will take care of reduction ratio variations.
The only thing that will not work is GoTo.. But, even this could be made to work (in Bartels system) provided you have encoders coupled to controller.
Hmm.. something to think about
However, I would still use timing belts and pulleys. They are not so much more expensive but they provide non-slipping reduction for PicGoTo or Bartels or Darren's or whatever driving system you choose...
Quote:
Originally Posted by alistairsam
Hi Bojan,
can you please clarify how you get the 1:2880 reduction ratio from 1:16,
is it after the worm and tooth reduction on the EQ6?
is it detrimental to use v belts and pulleys rather than timing belts? its just that I need a total reduction of around 800:1 for a step clock of 33Hz, and I can't get the matching timing pulleys or pulleys with tooth on the OD and Hub to make a gearbox with timing pulleys to reduce backlash.
i've been thinking of planetary gearboxes, i pulled out one from a cordless drill, reduction ratio is quite high, but not sure of backlash.
had a look at the stepper gearheads from various suppliers, they're quite expensive.
any recommendations?
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