1. How to test capacitor inside single phase motor?
Discharge the capacitor. Set the multimeter to measure resistance. Connect probes to leads of capacitor. The meter will show a reading and soon will display an open circuit (infinity). Note down the reading that was displayed for that short period. Repeat the test several times. Every test should show similar result for a good capacitor.
2. How does the wheel balancer work? What are the functions of the main components? 
Piezoelectric sensor get "vibration" signal and send it to CPU. Encoder board get "position" signal and send it to CPU. CPU calculate imbalance based on these signals, wheel dimensions and balancing mode. (Please contact us if you have more questions on this topic)
3. How does the wheel balancer work? What are the functions of the main components? 
Piezoelectric sensor get "vibration" signal and send it to CPU. Encoder board get "position" signal and send it to CPU. CPU calculate imbalance based on these signals, wheel dimensions and balancing mode. (Please contact us if you have more questions on this topic)