Voltage range on DC brushless motor.

Thread Starter

Emare

Joined Dec 8, 2017
23
I am building a dust mask for wood turning using a 12volt brushless computer fan and a battery from a cordless drill. The fan forces air through a filter onto the inside of my face shield. The first try worked very well using a 12v power supply but the AC power cord to the rig was a pain , hence the 20v lithium ion battery. Worked great for a few days ( fan was quite a lot faster ) but I think I burnt out the motor with the higher voltage. Trying again with a 14.4volt battery. Will the 12volt motor tolerate the 14.4 volts? Thanks for taking the time.
 

Wolframore

Joined Jan 21, 2019
1,922
Motors like all components are rated for certain voltage and power. If you’re exceeding the rating you are taking a chance at failure as you discovered. Without knowing a lot of detail about the motor windings, wire size, insulation.... etc... we would be guessing, why not add a switching DCDC regulator (that is rated for your motor) to drop the voltage to its recommended voltage.

another note 14.4 volt battery is most likely a 4S lithium ion. 14.4 is nominal voltage of 3.6V x 4 (cells). At full charge your actual voltage is Upwards to 4.3 x 4 or about 17.2V.
 

Thread Starter

Emare

Joined Dec 8, 2017
23
Thanks Wolfamore, given my technical limitations the switching regulator may be beyond my abilities. I was thinking of putting a resistor in series. What do the regulators look like and would they have been a part of the fan's circuit in the computer I salvaged the fan from? In the attached photo you can see 3 wires to the fan, a (+) a (-) and a 3rd. Would this be related to the regulator? Thanks for your help
 

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