If a rotisserie motor hums but the spit does not turn when the rotisserie is started, the cause is most probably

a. a lack of supply voltage.

b. overheated elements.

c. a defective motor.

d. jammed gears.

Knowing from experience with old gear driven pull back cars when iwas little id say gear jamming, those cars were built with faulty gears that always got stuck

If a rotisserie motor hums but the spit does not turn when the rotisserie is started, the cause is most probably a defective motor - Letter C. Most probably rotisserie appliances doesn't run on programs, which is rotisserie appliances are configured inside the machine.