Here are the internals of a cheap Microwave/Convection Oven combo. Electronics bay is pretty much the same as a standard microwave, with the magnetron, transformer & diode/capacitor voltage doubler, with the addition of an extra fan & a pair of nichrome elements to provide the convection oven function.
Convection blower which keeps the cooking vapours & smoke away from the elements, & circulates the hot air around the cooking chamber. This is a 12v DC centrifugal type blower.
The elements are inside this steel shield, air duct extends from the centre.
This oven has a pair of thermal switches on the magnetron.
The usual capacitor/diode voltage doubler in the magnetron power supply. The transformer is visible to the left.
Electronic controller PCB. This has a pair of relays that switch the elements & the magnetron transformer.
This is a 1500W hairdryer, death caused by thermal switch failure.
This is the switch unit. Attached are two suppression capacitors & a blocking diode. Cold switch is on right.
Heating element unit removed from housing. Coils of Nichrome wire heat the air passing through the dryer. Fan unit is on right.
Other side of the heating element unit, here can be seen the thermal switch behind the element winding. (Black square object).
The fan motor in this dryer is a low voltage DC unit, powered through a resistor formed by part of the heating element to drop the voltage to around 12-24v. Mounted on the back of the motor here is a rectifier assembly. Guide vanes are visible around the motor, to straighten the airflow from the fan blades.
5-blade fan forces air through the element at high speed. Designed to rotate at around 13,000RPM.