RepRap: Blog

Well, the MECI 12v DC motors arrived but the magnetic shaft encoders didn't, which means that they won't be here till Tuesday. No big deal.

The first impression of them is that they are HUGE! One of these would make 5-6 NEMA17's.

I fed 12v to one of them and it made a serious attempt to jump off of the work table. At 5v and roughly 1000 rpm (16 mm/sec) it is still putting out loads of torque.

I connected a 1.57v AA battery to the motor and it turns at a rate that looks to be about 300 rpm (5 mm/sec).

From there I went on to check amperage at the 3 voltage levels. Here is approximately what I got...

• 12v - 2.3 amps
• 5.5v - 2.1 amps (after motor warmed up)
• 1.57v - 1.7 amps (AA Battery)
  

All three amperage measurements were for the motor in an unloaded state. I doubt that the AA battery was capable of delivering much more amperage than it did. The important bit, however, was that the motor turned smoothly at that voltage and delivered a considerable torque.

Given the fact that this motor is a brushed DC motor measuring the resistance of the armature was a bit tricky. It appears to be about 0.7 ohms, however.

Tomorrow I plan to bolt one of these to the z-axis and cobble some sort of coupling to the threaded drive rod together. :-)