I dont know if this is possible but if you ohm the motor out providing its good, can you tell the voltage by a formula? I guess if you knew how many poles it has. I know you can do that on a/c motors. Not sure about d/c.

"As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my sweet ride." -Amen

56 Chevy 3100