Nick Ridgway
The resistance of a GOW bulb across the terminals is there to better match the motor and controller from the perspective of system dynamics and control system stability. Without it, a low-inertia motor will behave badly with feedback controllers.
Some decades ago I did some experiments with ECM Compspeed type A, a favourite of mine, with Portescap 1219, another favourite, connected to an oscilloscope. It revealed what was going on.
My write-up is available as a Manual sheet. If more explanation is needed I can up-rev it; please advise?