Motor to drive: maxon ec 9.2 10mm blushless https://www.maxongroup.com/maxon/view/product/624162
| Values at nominal voltage | |
| Nominal voltage | 4.5 V |
| No load speed | 13900 rpm |
| No load current | 34.7 mA |
| Nominal speed | 3620 rpm |
| Nominal torque (max. continuous torque) | 0.702 mNm |
| Nominal current (max. continuous current) | 0.27 A |
| Stall torque | 1.01 mNm |
| Stall current | 0.364 A |
| Max. efficiency | 50 % |
| Characteristics | |
| Terminal resistance | 12.4 Ω |
| Terminal inductance | 0.281 mH |
| Torque constant | 2.79 mNm/A |
| Speed constant | 3450 rpm/V |
| Speed / torque gradient | 15400 rpm/mNm |
| Mechanical time constant | 38.2 ms |
| Rotor inertia | 0.237 gcm² |
| Other specifications | |
| Number of pole pairs | 4 |
| Number of phases | 3 |
The design we came up with was:
In my tests, the motor aligned, made a few steps and then it looks like it goes to a lock condition:
e2e.ti.com/.../2024_2D00_02_2D00_26-17.27.03.mp4
I tested also to replace the LEDs parallel to the windings (H101, H103, H104) with resistors (the 2k2 were replaced with 0 Ohm) of 24 ohms to draw at least a current of 100mA to not fall into the "no motor" lock. No success.
I also tested to set the CONFIG-Voltage to 0V and to VCC also with no success. The result is always the same as in the video....
By the timing, i would say, it falls into a lock but i dont knwo how to figure out which one and how to mitigate it....
any ideas are very appreciated
Thanks!
-Tom
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