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Heat gun motor pcb ?

Waterworks178

Aug 21, 2022
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Aug 21, 2022
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I'm repairing a heat gun , I'm an engineer and only know very basic electronics, this tool has a dead fan, from what I read they use 240 v ac put through a heating wire as a resistor to run the 12v fan motor but I see no rectifier on the pcb , can anyone tell me how this pcb works ?


20231030_150329.jpg20231030_150312.jpg
 

Bluejets

Oct 5, 2014
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Oct 5, 2014
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Capacitor in series with the motor suggests it to be the voltage drop element.
Once again, crude but works so long as motor is completely isolated from the outside world.
 

ivak245

Jun 11, 2021
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If it has the heating element in series with the motor/ rectifier, they sometimes have a thermal fuse in there, mounted in or near the element. This cuts power to everything if it blows. Looks like a little silver bullet.
 

Alec_t

Jul 7, 2015
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Capacitor in series with the motor
They're in parallel. So the voltage dropper would be part of the heating element. I'd guess the set-up is as below (ignore the example component values) :-
1698768411454.png
L1 and L2 are interference-suppressing chokes (those black-sleeved items in your pic).
I haven't haven't shown the small caps connected to the motor terminals.
 
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