Part 3/7:
Replacing and Testing the Motor
The motor, dating back to the early 1940s, is a stainless steel-tanium device built with technology of that era. It was designed for 70 volts alternating or direct current. The brushes inside the motor were worn down and partially corroded, causing sparking. New carbon brushes—originally manufactured around 1943—were carefully installed to restore proper contact.
Testing involved connecting the motor to a variable power supply set to 70 volts. Initial power-up resulted in some sparking, expected due to friction and the age of the components. Gradually reducing the voltage demonstrated the motor's proper operation, with no sparking at lower voltages (~110V), confirming good function and minimal internal resistance.