The motor is a three phase brushless DC (BLDC) motor with Hall sensors. The motor is from an abandonded project many years ago where it ran a battery operated floor buffer. The controller from that system was not setup to vary the speed of the motor, so I used a Kelly controller.
The bottom circuit board is devoted to the connections necessary for the Kelly controller. For example, this contained the pre-charge resistor, the connection to the Hall sensors and the connections for the main contactor.