Baserunner Controller User Manual
Rev 1.0
5.5 Tuning the Sensorless Self Start
Advanced Setup
If you are running in sensorless mode, then you may need to tweak the
sensorless self start behaviour.
When the brushless motor is run without hall sensors and started from a
complete stop, the motor controller attempts to ramp up the motor’s rpm to a
minimum speed so that it can latch onto the rotation (closed loop).
It does this by first injecting a static current into the phase windings to orient the
motor into a known position. The controller then rotates this field faster and faster
until reaching the “Autostart Max RPM” value.
As initial values, set the
“Autostart Injection Current” to
half your maximum phase
current, an “Autostart Max RPM”
to 5-10% of the running motor
rpm, and an “Autostart Spinup
Time” anywhere from 0.3 to 1.5
seconds, depending on how
easily the motor can propel the
bike up to speed.
On bikes that you pedal to help
get you underway, a short 0.2-0.3
second ramp will often work best,
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