no hum would seem to be either a no-power scenario or a blown primary winding (consistent with an overcurrent situation causing the breaker to trip).
do you have a multimeter? If so please check:
1. the continuity/resistance of the primary winding on the motor (take a photo of the electrical connections if you're not clear on where to measure. and measure across the live and neutral terminals at the motor too. NB - MAKE SURE THE POWER AT THE BREAKER IS OFF FOR THIS... The meter should be in ohms mode.
2. if you feel competent to do so, with the power at the breaker ON and the motor on (if it has a switch), carefully measure the voltage across live and neutral terminals at the motor. the meter should be in AC volts mode (500v or thereabouts if not auto-ranging). If you're getting close to zero then double check that your meter is not in DC mode.
if there is normal resistance across the primary, and power getting to the motor then (power off) double check all the wiring terminals to make sure they're snug. If so then I'm surprised there's no hum, even if the cap was dead (you can test a cap with a multimeter too - whilst they tend to _lose_ capacitance over the years they should still work; and when they fail they fail 'down', so the resistance across the capacitor drops very low. Measuring with a multimeter in a normal cap you should see resistance fluctuate from open line to somewhere in the kilohms range. And some multimeters happily measure capacitance, so that's even easier). No hum would usually be
A couple of other thoughts:
a. some motors have a fuse in the wiring box.do check for this. the fuse could be just a wire on a circuit board near the wiring terminals. shine a light down there and have a look for anything looking odd.
b. my fuse board by the pool is 'secondary'. so there is also the primary fuse box in the house (or wherever) to check. But you say that there is measurable power going to the motor, so not the issue here.
