wierd mosfet issues

[eatthis]

iv got 4 basic mosfets all new and different makes (so not a bad batch)
1 went pop straight away for no apparant reason (gearbox is fine and wiring was correct)

the other 3 are all live as soon as i connect the battery regardless of what im doing with the trigger wire.

[madwelshman]

Re: wierd mosfet issues

and you genuinely believe its nothing you've done?

[javaoverride]

Re: wierd mosfet issues

sounds like you have wired it backwards

[a_flea]

Re: wierd mosfet issues

iv got 4 basic mosfets all new and different makes (so not a bad batch)
1 went pop straight away for no apparant reason (gearbox is fine and wiring was correct)

the other 3 are all live as soon as i connect the battery regardless of what im doing with the trigger wire.

Live or signalling the motor? Because they should be live with the battery connected...

[eatthis]

Re: wierd mosfet issues

sounds like you have wired it backwards

1 side has 2 power leads the other side had 2 power leads + trigger wire
the 2 on their own are the supply (from battery)?
the 3 goto the gb?
in the answer is yes then iv wired them correctly

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Live or signalling the motor? Because they should be live with the battery connected...

live as in the motor goes weeeeeeeee as soon as battery is connected

[sj_asc]

Re: wierd mosfet issues

What FET's are you using? Not using them inline with charging the battery?

[North West Outpost]

Re: wierd mosfet issues

Unlikely to find 4 duffers in one delivery. Particularly if they are different models.

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1 side has 2 power leads the other side had 2 power leads + trigger wire
the 2 on their own are the supply (from battery)?
the 3 goto the gb?
in the answer is yes then iv wired them correctly

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live as in the motor goes weeeeeeeee as soon as battery is connected

You have wired them wrong!

Just because you have 2 wires going to the battery and 3 going into the gear box doesn't mean you have it wired right!

[Skolob]

Re: wierd mosfet issues

Another problem could be the motor +ve lead shorting on the gearbox shell and making the trigger switch go live.
check wiring around gears for damage and also check the motor plate to see if its shorting the motor terminals).
As above, the most likely cause is the simplest, which is a wiring fault either incorrect or short.

[eatthis]

Re: wierd mosfet issues

Unlikely to find 4 duffers in one delivery. Particularly if they are different models.

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You have wired them wrong!

Just because you have 2 wires going to the battery and 3 going into the gear box doesn't mean you have it wired right!

1 of them is prewired for the battery so if the wirings wrong that 1 came wrong iv wired the others the same

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Another problem could be the motor +ve lead shorting on the gearbox shell and making the trigger switch go live.
check wiring around gears for damage and also check the motor plate to see if its shorting the motor terminals).
As above, the most likely cause is the simplest, which is a wiring fault either incorrect or short.

iv wired them up outside the box to remove issues like that

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[mrpugster]

Re: wierd mosfet issues

I had a very similar issue before when I was testing some new Fet's once. I hooked everything up outside the GB and also used some gator clips like yours in the photo, either the fet didn't work or motor just spun. It wasn't till I soldered the connections then noticed it was working fine.

I can see the multi-metre is reporting current so I know this sounds odd and I MAY have done something stupid etc and I know s**t about electronics but worth a shot if you've tried everything else....

[eatthis]

Re: wierd mosfet issues

I had a very similar issue before when I was testing some new Fet's once. I hooked everything up outside the GB and also used some gator clips like yours in the photo, either the fet didn't work or motor just spun. It wasn't till I soldered the connections then noticed it was working fine.

I can see the multi-metre is reporting current so I know this sounds odd and I MAY have done something stupid etc and I know s**t about electronics but worth a shot if you've tried everything else....

il try it wired into the box but it shouldnt make any difference.
its on volts not amps btw to check current you have to put the meter in series with the circuit to check volts its paralel

[North West Outpost]

Re: wierd mosfet issues

They are not how I wire fets into guns.

When I make fets I make them with 4 wires as it is easyier to wire into the gear box, have you re wired the gear box to match the fet?

[eatthis]

Re: wierd mosfet issues

They are not how I wire fets into guns.

When I make fets I make them with 4 wires as it is easyier to wire into the gear box, have you re wired the gear box to match the fet?

i dont know about the 4 wire method
yes i rewired the box basically connect the lives together on 1 side of the switch and the mosfet trigger wire goes to the opposite side of the switch this means the switch connect the mosfet trigger to +ve which then turns the fet on

[eatthis]

Re: wierd mosfet issues

they do the same when wired into th egearbox

[mrpugster]

Re: wierd mosfet issues

if you're still having problems maybe a more detailed pic would be useful, everything wired up outside of the GB, including switch, motor, fet and batt...