problem after mosfet installed

[Garrym]

hi guys, running a classic army m4 cqb navy seal, bought it used and its had internals upgraded (not exactly sure in what way) one thing i do know though is it came with a mosfet kit and got it installed and gun fires for a short time then stops, felt the motor getting really hot and the mosfet chip got a little hot. Any ideas whats causing it to heat up and stop? I initially had problems with the mosfet shorting out but got that sorted now i have this...help! incase this matters, the motor is a high performance high torque classic army motor.

Cheers

Garry

[sparrowhawk]

Re: problem after mosfet installed

what battery,grade of wiring and connectors are you using

[Garrym]

Re: problem after mosfet installed

2200ma bat on deans Not sure on the wires its the ones came with it the mosfet is extreme fire sw-ab-long

[sparrowhawk]

Re: problem after mosfet installed

is that a lipo battery

[Genista]

Re: problem after mosfet installed

That mosfet has thermal, resetting fuses. Sounds like you are tripping them. A high torque motor will be pulling extra current from your battery, so there could be a mismatch/over current situation making the mosfet go in to protect.

You're either looking for part of the system that is under too much strain or possibly another wiring shorts.

When it shoots, does it sound ok? does it turn over quickly, or is it slugish?
What FPS is it shooting at?

Could even be a poor shim job.

[Garrym]

Re: problem after mosfet installed

I'm running a standard ni-cad batter its a 2200 though so its quite big. the battery and the motor were working on the older wiring without a problem but when the mosfet went in this has happened.

Its firing fine for the first sounds fine, fires crisp n sharpe for first few then cuts out not sure on the fps but hitting a can with it and it dented the can at the corner of it where it gets fat so it seems to have a bit of power to it

[sparrowhawk]

Re: problem after mosfet installed

You could contact extreme fire direct,the fella who produces them is very helpful

[No1_sonuk]

Re: problem after mosfet installed

If the motor stops and gets hot, it's probably stalled due to a mechanical fault, or not enough current getting to it to rotate, but enough to heat up the coils.

[Samwise]

Re: problem after mosfet installed

Its very unlikely to be a fault with the MOSFET; the guy who makes them basically invented them (for airsoft) and pretty much never sends out dud units.
He's the most helpful guy on the planet though, so dropping him a line would be a good move too.

Something in your setup would seem to be causing excessive resistance.
This will cause a build up of heat which will (helpfully) trip out the FET fuse.
The usual culprits are tight shimming, the motor sitting too high, poor soldering/inappropriate wire or a short-circuit.

Can you give us some more info on exactly what was wrong with the MOSFET install last time?
Were some of the wire ends not in the screw terminals properly and shorting against each other?

[mirlock]

Re: problem after mosfet installed

as he said up there ^^ but also check pinion gear and bevel gear line up etc.
this will cause the motor to run hot and trip the mosfet

[Garrym]

Re: problem after mosfet installed

hi guys thanks for the help, it ended up being wiring had a tiny little cut in it and when it was put together it opened more and had contact with the body, a royal pain in the ass, so I've just rewired the lot seems to be running fine....until i broke the connector to the motor so had that put back on and will test her out tonight and fingers crossed shes fixed for at least to get me through a game not had a full skirmish day yet. if anything else goes wrong i'll be checking the rest of the info you've said. Thanks again guys!