humming motor sounds like the capacitor, (white tube like thing in the electric box) NOTE: if you open the electric box DO NOT TOUCH THE TERMINALS,
sometimes happens when you use long extension cables
aquaspray.co.uk, May 2009
Humming suggests the motor is somehow stalled - good job the fuse pops before the motor burns out - I would imagine a mechanical problem causing your motor to stall, the current then rising until the fuse is overpowered.
