fetless

[windspeed]

I pulled this out of a 24 volt controller

could anyone tell me where I could get one or an equivalent

Windspeed

[spinningmagnets]

Go to the electric bicycle forum over at "endless-sphere" and ask Fechter, he is the FET guru.

http://endless-sphere.com/forums/viewtopic.php?f=1&t=5306

[dnix71]

All FET's except jfets have 4 terminals. Are you sure it's not a zener?

[dnix71]

The third line of numbers looks like SR

That would make it a rectifier.

[boB]

It's more than likely this FET...

IXFH80N08  80 Volt  80 Amp

http://ixdev.ixys.com/DataSheet/98810.pdf

(most likely)  but maybe a higher voltage one:

IXFH80N085  (85V) or  IXFH80N10 (100V) IXFH80N15 (150V) etc...

In fact, some distributors have the ISFH80N085 which should work

fine in a 24V controller.

Future Electronics has some in stock but they're like $18 a pop.

http://www.componentsuperstore.com/

boB

[Flux]

I will go with boB, its an Ixys mosfet. Can't read the last part of the number to get the voltage grade but you can choose that depending on the system volts.

Ixys devices are expensive compared to other manufacturers but they do seem to be tough.

You can find alternatives from other manufacturers cheaper but I would go for a higher spec if you do.

Unless you find what caused the trouble you may have an instant fry with the replacement.

Flux

[DingBat]

So what's the fourth pin?

I know about Gate, Source and Drain.

[Flux]

Three are enough for me.

Flux

[BigBreaker]

Sometimes in a power MOSFET the body and source are left unconnected and both leads are exposed, in addition to the drain and gate.

[boB]

3 legs and one TAB (mounting, heat sinking tab), are the 4 connections.

Middle leg AND tab are usually the drain and are connected together.

boB

[dnix71]

Yeah, not cheap at all.

http://oemstrade.com/search/IXFH80N20

lists online sellers.

[GlutealCleft]

In this case, the tab is on the back, although the front of the tab is covered.  However, because of the damage, you can still make out just a tiny bit in this photo.

However, the "Four Terminals" is generally a function of the package, not of it being a FET.  Look at those available in the SOT23 package.  Three pins, no more.