RoboteQ AX2850 - Manual (Page 46)

General Operation
46 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
The relation between Battery Current and Motor current is given in the formula below:
Motor Current = Battery Current / PWM Ratio
Example: If the controller reports 10A of battery current while at 10% PWM, the current in
the motor is 10 / 0.1 = 100A.
Important Warning
Do not connect a motor that is rated at a higher current than the controller. While
the battery current will never exceed the preset Amps limit, that limit may be
reached at a PWM cycle lower than 100% resulting in a higher and potentially unsafe
level through the motor and the controller.
Regeneration Current Limiting
The AX2550’s current sensor is capable of measuring current in the reverse flow (regener-
ation). Using this capability, the controller will automatically relax the braking effect of the
power output stage to keep the regeneration current within safe values. Because of the
controller’s high current handling capabilities, this protection mechanism activates only
when abrupt deceleration are applied to high-inertia, ultra-low impedance motors.
Off
Motor
Vbat
On
FIGURE 19. Current flow during operation
Off
I mot
Avg
I bat
Avg
On
FIGURE 20. Instant and average current waveforms