Friday, July 04, 2008
NINCO NC-6 Test
The NC-6 "Crusher" may have been the first of the super-power long cans. NINCO claims 23,500 RPM at 14.8 volts; or 19,054 RPM at 12v, no load. Torque is claimed to be a whopping 350 gcm at stall, at 14.8v; or 284 gcm at 12v. The NC-6 remains NINCO's top of the line race motor, and is the spec motor for the 2008 NINCO World Cup.
We acquired a new sample NC-6 courtesy of Main Line Hobbies, a well-established, full-line hobby shop near Philadelphia, PA, USA. Thank you Les! Main Line Hobbies is hosting the Philadelphia Regional NINCO Cup Race, as part of the '08 NINCO World Cup series.
A series of tests were conducted on this NC-6, with some interesting findings.
First, we found that the NINCO pinion could be removed from the shaft with finger pressure alone! We just pulled it off, with no need for a pinion puller. Hardly what you want with a high-torque motor.
The NC-6 weighs 32 grams; magnetic downforce on the Magnet Marshal is 25 grams inline, and 23 grams anglewinder, at 1.2mm ground clearance.
After 45 minutes of free run-in on 6 volts, 19,450 RPM at 12 volts was measured with the tachometer. This is within the range of NC-6's previously tested here (19,189-20,130 RPM). Bypassing the turquoise inductor (in series with one motor lead) resulted in 210 extra RPM.
Next, we cut the wrapper away from one of the case slots, to allow marking the poles for the torque test, and for better cooling (photo below):
Voltage was re-set to 6 volts, and nine readings on the torque-arm tester were taken in various positions, around a single revolution of the armature. The test was then repeated, with time allowed for cooling down. With poles centered in the case slots, a maximum of 98 grams was measured, for each of three poles. With the poles slightly leading, and slightly trailing that position, readings of 74 to 78 grams were recorded. When all readings were averaged, 88 gram-centimeters of torque was determined, at six volts. Doubling the reading for an indication of 12 volt torque resulted in 176 gcm/12v; that was further confirmed by two blasts at a full 12 volts, where 156 and 176 gcm was actually measured, accompanied by a puff of smoke from inside the motor each time. Follow-up testing on the tach showed 19,200 RPM/12v, with a 250 RPM loss, possibly due to soot on the brushes and commutator. None of the visible windings were burned. The commutator could not be examined due to the crimped case.
With measured no-load RPM and stall torque as a basis, 12 volt power was computed at 8.6 Watts, a far cry from the 13.5 Watts of power we would see if the motor developed its claimed 284 gcm/12v torque. By comparison, the lighter, smaller Slot.It V12/3 21.5k "orange endbell" produces 9.1 Watts, conservatively rated, with actual performance tested to 9.8 Watts. The NC-6 developed less than two-thirds of its claimed torque. And watch that loose pinion! Even so, 176 gcm torque is plenty, and takes a strong chassis to contain. The record of the NC-6 in actual competition speaks for itself, and shows it to be capable of moving cars down the track very fast.