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using low voltage on DC fans

Greg Smith
 

I am using an ATX power supply for my Tortise switch machines.  I have a number of 3.3 VDC and 5 VDC wires that at present are not being used.  Can I use 3.3 or 5 VDC on 12 VDC fans without damaging the motors in the long run?  They run okay, a bit slower than when on 12 VCD of course.
Greg
ps - I am going to set the fans up behind my Digitrax Command Station and Boosters for a bit of extra cooling.

Steve Haas
 

 

>>>>> I am using an ATX power supply for my Tortise switch machines.  I have a number of 3.3 VDC and 5 VDC wires that at present are not being used.  Can I use 3.3 or 5 VDC on 12 VDC fans without damaging the motors in the long run?  They run okay, a bit slower than when on 12 VCD of course. <<<<<

 

Greg,

 

You’ll be fine.  What you propose to do is roughly the equivalent of running a good old fashion 12 DC motor in an old Athearn engine at somewhere around  27% and 42% of full throttle on that old Power Pack you got with that first train set so many years ago.

 

Best regards,

 

Steve

 

Steve Haas

Snoqualmie, WA

 

The fans are in reality brush-less DC motors and therefore rely on internal electronics to make them rotate.  What happens when you under drive them therefore cannot be predicted.  Some fans are rated to work down to 5 Volts but others don't say.  If you give me the model and part number I will see if I can find its' electrical rating.

These are not costly devices so why not purchase one rated for what you want to do.  3.3V are rare but if you can run at 5 Volts can find a lot of choices.

https://www.digikey.com/product-detail/en/cui-devices/CFM-5010V-052-300/102-4365-ND/7620539

Be sure to check the actual output of your ATX supply as they are designed for heavy loads on the low voltage outlets and may not regulate properly without such.

Best Regards,

Ken Harstine

Greg Smith
 

Ken
Thank you for the information.  I have a couple of 12VDC fans – think I paid $2.00 for them – so as you say they are not expensive.  They do run on 3.3 and 5 VDC.  Mainly I was curious as to their likely longevity and also to find a use for the 3.3 VDC outputs.   One sure way to find out is to run them and see if they last.  If they do not I will replace with 5VDC fans. 
I am new to this and many basic (dumb) questions are forth coming.
 
Greg Smith
ps – I have checked the voltage output on the ATX power supply and all three voltages are very close to rating.