RAMPS 1.4 testing stepper motor reprap

This is Ramps 1.4 and arduino mega 2560. steppers are: Frame size 42 x 42mm - NEMA 17 1.8 degree step angle Length 47mm Holding torque 44 N.cm (4.4kg.cm, 62oz.in) Voltage 2.8V Current/Phase 1.68A Resistance/Phase 1.65ohm Inductance/Phase 2.8mH Inertia 68g.cm Bipolar, 4-wire tested vith this file: http://reprap.org/mediawiki/images/1/12/RAMPS14_test.zip working absolutely fine!