[sanddrag]

I've done break-in on a number of FRC gearboxes over the years, and let me tell you, it makes a big difference. When running properly, a typical gearbox like the Nano should draw between 2.3 to 2.8 Amps per CIM with no load, from a 12 Volt supply.

Yours are drawing too much. You have something binding.

One year, I had a tight running gearbox, and no way to remachine the plates to increase center distance, and no lapping compound available. I took a bottle of car polish and poured it right in the meshing gears. A few cycles of this, and 20 minutes later, and a bunch of cleanup, and it ran like butter and current draw was less than half of what it started at.

For those of you designing your own gearboxes, make sure to use precision ground bearings. I've seen teams build gearboxes with non-precision general purpose bearings, that just aren't rated for the loads or speed they see, and they fail. I've even seen sloppiness in brand new bearings cause a gearbox to bind enough to nearly stall a CIM.