a. How 240 vac is delivered to the appliance. My answer is by dropping 240v to 120v for L1 and 120v for L2. thing like heating elements will combine L1 and L2 creating the 240v they need to run.
How to use voltage measurements to locate the fault in an electric dryer that is
not heating. My answer is i would first check voltage at the source L1 to N for 120v and L2 to N for 120v then i would check L1 ands for L2 for 240 if yes then i would get the wiring diagram locate the heater coils and thermistor for proper voltage.
I hope im on the right track?