Is this gonna burn my house down?

Silver 6

Silver 6

Active Member
Haven't soldered anything yet, just wanted to check a few things with anyone with experience in electrics.

Is the power supply safe for the fan? I had it running on USB with the switch at 5v 2A? But was slow.

Would the switch be better on the negative side so any power still in the power supply can go through the fan?

And lastly, is the switch safe at all or need to shut that box off at the wall?

Thanks, any help appreciated
 

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spliffendz

spliffendz

Well-Known Member
I can't remember the science behind it but if it's a pc fan, I made a plug for it with an old multi-adaptor charger plug, that way you could switch the voltage to the right setting.

There are videos on youtube, but I'm sure an expert will be along shortly.
 
Silver 6

Silver 6

Active Member
I do have a dial on it, that's the round thing I forgot to add pic, do you reckon if I keep it dialed down a bit it will be okay?
 
Attikus112

Attikus112

Well-Known Member
You're fan is only rated for 12v and you have a 15v supply so there's a good chance you'll kill the fan. Also, your potentiometer is wired up as a rheostat so it won't act as a voltage divider just a current limiting resistor. Lastly, if you stick with the setup, get some tape or heatshrink over your splices to prevent a short.
 
Silver 6

Silver 6

Active Member
Attikus112 said:
You're fan is only rated for 12v and you have a 15v supply so there's a good chance you'll kill the fan. Also, your potentiometer is wired up as a rheostat so it won't act as a voltage divider just a current limiting resistor. Lastly, if you stick with the setup, get some tape or heatshrink over your splices to prevent a short.
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Yeh definitely gonna tape them, thanks.
you lost me with the technical stuff I basically know black to black red to red
Same question with the dial tho you reckon lowering it on the dial will keep it alive for longer?
 
Attikus112

Attikus112

Well-Known Member
Your fan will draw 4.56W assuming 12v and 380mA so anything rated at a higher wattage than that would be fine.

A rheostat is just a variable resistor, if you wired your knob with three wires it would act as a potentiometer or a voltage divider.

I tend to agree with others though, that shouldn't be an overly loud or powerful fan so either get a 12v regulator thats rated for 0.38A or higher and run it at full speed or get one of those adjustable dc power supplies.
41eBUkYyLDL._AC_SY400_.jpg
51ND862tLUL._AC_SY400_.jpg
 
Attikus112

Attikus112

Well-Known Member
Silver 6 said:
Oh and should I use the switch ?
Click to expand...
As long as the switch is rated for the current going through it, it should be fine. All conductors have resistance to them so there will be a voltage drop across the switch. The voltage drop * the current draw is the power dissipated by the switch. If it's not getting warm though it should be fine.

Having it switch the positive lead wire is preferred. If you were switching the ground side rather than the positive you could become the path to ground which wouldn't be great. Not a huge concern for these voltages but something to consider.
 
Kassiopeija

Kassiopeija

Well-Known Member
Silver 6 said:
wattage
Click to expand...
wrong stat to look at,
match the Volts (can be less, but not more)
I got some of these in 1 Ampere, and some with 2 A. Still, I can savely support half-a-dozen, or dozen, 12V Arctic F12 PC fans, which consume 0.15A @ 12V.

This ones perfect, I drive 6 fans with it, but it could be more
IMG_20200619_141452~2.jpg

if you have multiple fans, then these also come in handy

InLine 33436 Lüfter Adapterkabel, 3pol Molex Buchse an 6x 3pol Molex Stecker: Amazon.de: Computer & Zubehör

InLine 33436 Lüfter Adapterkabel, 3pol Molex Buchse an 6x 3pol Molex Stecker - Kostenloser Versand ab 29€. Jetzt bei Amazon.de bestellen!
www.amazon.de

no need to solder at all
Cheers
 
Silver 6

Silver 6

Active Member
So I wanna change supply to 12v or less with 4.5 watts or more

Thanks for the input guys much appreciated
Glad I asked now haha
 
B_the_s

B_the_s

Well-Known Member
The power supply can easily supply the additional amperage that a 25% higher voltage will push. You'll shorten the life of the fan but I doubt anyone but the mfr could tell you how much. The additional current will break down the insulation on the wire in the coil faster over time. Its only shellac. And higher rpm will wear the sleeve bearing faster. Got an IR temp gun? If so, you could watch the temp of your power supply and fan motor to see if you notice operating temp beginning to climb.
 
Silver 6

Silver 6

Active Member
B_the_s said:
The power supply can easily supply the additional amperage that a 25% higher voltage will push. You'll shorten the life of the fan but I doubt anyone but the mfr could tell you how much. The additional current will break down the insulation on the wire in the coil faster over time. Its only shellac. And higher rpm will wear the sleeve bearing faster. Got an IR temp gun? If so, you could watch the temp of your power supply and fan motor to see if you notice operating temp beginning to climb.
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Nah don't have one, haven't got an answer on what the dial will do for it, will it be okay if I run it lower than high speed ? Norlt sure how it works if it drops volts or amps or whatever
 
TreeFarmerCharlie

TreeFarmerCharlie

Well-Known Member
Silver 6 said:
Nah don't have one, haven't got an answer on what the dial will do for it, will it be okay if I run it lower than high speed ? Norlt sure how it works if it drops volts or amps or whatever
Click to expand...
If you don't have a basic understanding of electricity or electronics then you really are better off just getting a fan controller that is made for that type of fan.

Just get this...it's $15.99, comes with the power supply, speed selector, and fan.
 
BostonBuds

BostonBuds

Well-Known Member
What are you using the fan for? I have a few fans and power supplies I collected through the years and even when i matched them up properly I was still disapointed and they weren't strong enough for much. Your'e on the right track and that power supply is too much, you will burn out the fan.
20200619_091744.png20200619_091719.png
 
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