Hi James,

One way to start the motor at high speed is to ramp up the speed which you have already tried out and it is not helping you.

Another way is modulate the power volatage to the motor. Means you have to insert high voltage spikes only during the start. Once the motor has overcome its inertia then you can withdraw these high voltage spikes. If you apply high voltage permanently then this will result in heating up the resistors that you have connected in series.

As per my opinion you do not need those resistors as they are not helping you in solving your problem whereas they are making the problem worse.

Reduce the sense resistors to 0.39 ohms but then you need to set the chopping voltage such that the current flowing through the L298 outputs should not go beyond 2A else L298 will burn out. If you want to increase the current through L298 beyond 2A then you can connect two L298's in parallel. By doing this you can increase the current to 3A.

One trick is to set the comparator voltage such to get optimum performance form L298.

Best of Luck

Girish R. Ghanekar