Hello brickers!

I try to build a compressor (like the 8868 one), but I am not sure which motor to use.

PF M-Motor, PF XL-Motor or should I stick to the older Motors?

Regards,

RockeTeK

If you gonna use the small pump, then I would say the M motor, it's faster and smaller. If you gonna use a big pump, then use a XL motor. Thats how I would do it.

The 8868 only has one pump (and also uses half it's stroke) so it's very underpowered. However if you intend to use it then I would use either the m motor for quite operation, or the RC buggy motor to thrash the poor little pump! The old style ungeared 9v motor with a single stage of gearing down may also be a good option as it is quite powerful (more powerful than the motor that replaced it anyway).

I used one M motor for two small pumps in my MOC and it was powerful enough to supply more that 5.5 meters of penumatic tubing.

The RC motor is the best choice overall, but the M motor also works fine. I use this with a 1:3 gearing on the RC motor and it doesn't break a sweat up to 45psi or so, at which point the tubes pop off.

You want to make the pumps go through the full stroke, and ideally have at least two of them in a double-acting configuration. The original 8868 compressor design is lousy (it was admittedly the first one they made), only going through half the stroke and running out of steam quickly.

The RC motor is the best choice overall, but the M motor also works fine. I use this with a 1:3 gearing on the RC motor and it doesn't break a sweat up to 45psi or so, at which point the tubes pop off.

Did you manually switch it off or did you make a pressure switch to stop the compressor?

Thanks

Edited January 24, 201114 yr by freakwave

I just turn it off manually when the pressure is high enough. The hoses and fittings are designed to automatically pop off if the pressure goes too high. In practice, it's better not to go above 30psi or so for extended periods anyway.

Thanks for the advice, I'll give it a go...