Need help with Badsey

I have a Badsey sport 24V. Last nite at made a little smoke. After a long down hill run the large transformer on the board smoked after cooling the motor did run. The controller is a curtis 1204-102 175 current. Motor is a Bosh 750(came parts be found for this).Can some one tell me what the transformer is for and what a part number would be. Thank Jerry