some quick electrical sanity checking

AtaRo said:
To removed the delay the converter can be wired in a way that it is always powered on when the airsoft is inoperation, then insert the on/off switch for the motor at the ouput of the converter in series with the motor.
A main power switch for the converter then can be installed in series at its input to put it, in its always on state.
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This is the thing, i'm trying to avoid using the second switch as its a weak point. Kinda hard to describe but basically the way its set up any over-zealous pressing of the trigger has the potential to kill the microswitch.
 
adolf hamster said:
This is the thing, i'm trying to avoid using the second switch as its a weak point. Kinda hard to describe but basically the way its set up any over-zealous pressing of the trigger has the potential to kill the microswitch.
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I dont think he means use the second switch but run a second set of wires from the main trigger switch so that the dc-dc converter r is always live but not connected to the motor untill you pull the trigger and close the circuit.


Guessing trigger is linked to a much sturdier switch but the wiring for that might be buried In your gearboc
 
I just did some tests on the banggood converter, with an input of 11 volts and an output of 6 volts,

Open circuit output took about 10 mS to reach 6 volts, same with a 12 Ohm load ( 0.5 amps).

Dunno if this is fast enough for you ?
 
Tefal said:
I dont think he means use the second switch but run a second set of wires from the main trigger switch so that the dc-dc converter r is always live but not connected to the motor untill you pull the trigger and close the circuit.

Guessing trigger is linked to a much sturdier switch but the wiring for that might be buried In your gearboc
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yeah the main trigger is a much sturdier design, fortunately with the mosfet installed i have external access now to the trigger contact wires/main motor wires so running power from there won't be too big of an issue.

@lotus7 thanks for testing that out, sounds pretty decent, this thing runs at ~1200rpm but by default really short bursts doesn't give the motor enough time to spool and feed (the fix is just to fire a longer burst of 1-2 seconds) assuming it's ramp down is something similar it might be just the ticket.
 
well, converter arrived, looks like it'll do the job perfectly. have it wired up to the mag and tested working just fine. it's nice that if needs be i can up the power for a future where i do some tinkering and up the rof......

now all i need to do is get the reciever fixed and have the thing put back together.
 
necro time

so after some extensive mechanical surgery i've finally had the chance to give this thing a test in-situ.

unfortunately, it blew up, so i guess we're back to the drawing board.

to recap:

main battery is a 11.1v lipo

there's a single set of trigger contacts wired to a mosfet which switches power to the main motor

the second smaller motor is 6v and ~2A which i need powered at the same time as the main motor
 
You didn't use a capacitor or inductor, this stops things blowing up as excess electricity is stored in the capacitor or inductor which by the way inductors don't store energy. Its crazy stuff.

Resistors are useless if the energy supply is higher than actual usage. They might stop a certain amount of electrons flowing but not all.

Am out as my electronic days are well over. :p
 
itchy said:
You didn't use a capacitor or inductor, this stops things blowing up as excess electricity is stored in the capacitor or inductor which by the way inductors don't store energy. Its crazy stuff.

Resistors are useless if the energy supply is higher than actual usage. They might stop a certain amount of electrons flowing but not all.

Am out as my electronic days are well over. :p
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Inductors are good fun - you can easily build up massive voltages if the circuit isn't configured right (cap tank with inductive "kick back", etc.) and destroy all kinds of things.
 
Rroff said:
Inductors are good fun - you can easily build up massive voltages if the circuit isn't configured right (cap tank with inductive "kick back", etc.) and destroy all kinds of things.
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Had a few of them with un discharged capacitors, they hurt like hell. :D

Never had a inductor discharge hurt me though. I think from time ago is that once voltage is not applied then inductors discharge right away were caps keep a good charge no matter what.
 
itchy said:
Never had a inductor discharge hurt me though. I think from time ago is that once voltage is not applied then inductors discharge right away were caps keep a good charge no matter what.
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It isn't the inductor on its own that is the problem - its the combination with capacitance in the circuit if you don't have say a diode setup for discharge (usually in use for things like crude boost converters). There is a good video about it somewhere on YouTube but annoyingly I can't find it from a quick look.
 
Did you heatsink the regulator? don't really have my head in the details here but if the current is high they definitely need it and not all have thermal shutdown, etc.

EDIT: Oh if its one of those cheaper buck/boost type boards from China, etc. a lot of them can't handle more than about 60% of their rated load without going pop :s (they are generally pretty useful but often need to overspec on them).
 
Rroff said:
Did you heatsink the regulator? don't really have my head in the details here but if the current is high they definitely need it and not all have thermal shutdown, etc.
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fair point i did not, in fact the opposite i had to have it wrapped up because it's being tightly crammed into a metal body and i couldnt afford shorts.

thing is it didn't go pop in testing with the wrap on, so not sure it's a thermal issue.
 
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