Quoted from oxowhiz:
I actually used the IRL540NBPF which goes up to 36A, but even 54A would probably blow because a 0.8 ohm (AC flipper) coil draws 60A at 48V! Later I switched to non-logic level IRF540xx & IRF530xx (for the lighter score counter coils).
I thought I might add something being missed here.
A coil that measures 10 ohms with a meter does not present as a 10 ohm inductor.
It can be dramatically different to the dc measured value based on the number of turns, the thickness of the wire
& the density of the metal core.But it will always be a higher value than the DC measured. approx for pinball 1.4 x ohms.
A coil without an iron core will present the DC measurement as a load and is not an electromagnet.
Have 4 critical specs to take into account , break any of these thresholds = dead transistor
2,max reverse voltage (why we put a flyback diode in place)
4,max power - the most relevant
Transistor with 100w power - 100volts - 50amp ratings assumed
50volt supply & 5 ohm load = 10amps 50v x 10A = 500watts dead transistor
100volt supply & 100 ohm load = 1 amp 100v x 1A = 100watts warm transistor
25volts supply & 10 ohm load = 2.5 amps 25v x 2.5 =62.5watts happy transistor
Generally engineering at 75% of the transistors rating is best.
I hope this helps fill in some blanks