It is the same as double-plate clutch, difference is that this one has more than 2 friction plates.
Usually operate in oil bath.
Advantage – much more friction force and less wearing
Disadvantage - expensive
Totally different from other types.
There are two clutch plates as normal clutch.
In diaphragm spring place are used magnetic field that is produced by solenoid coil, electricity and iron powder.
Main principle is magnetization.
Advantage – instantaneously engaging
Disadvantage – expensive and hard to put together