Hey everyone, just about to start the build of my charging station, but I had one last question in regards to the fans.

They're little 60mm 12v dc case fans which I plan on soldering directly to the power supply (it won't get too hot to begin with, but these are an extra precaution anyways) as I've seen countless do with a similar build; unfortunately the wires are just barely too short.

When looking at the wires, I see there are three coming from the fan (obviously line, neutral and ground), but with the adaptor that makes the wires reach there are only two.

Would it be safe for the fan and power supply if I snipped it after the adaptor and wired it without what I'm assuming is the ground?

Thanks in advance! This really is a great and helpful community here

Regards

 

What is the voltage rating of the fan and can you identify the power pin polarity ?

 

Are you sure these ae AC fans? Could be DC fan with a tach output or fan speed control input. Also, if you really don't need cooling, consider only 1 fan. Less noise, less heat, etc.

ak

 

They're little 60mm 12v dc case fans which I plan on soldering directly to the power supply

12 VDC case fans likely do not have a Line, Neutral and Ground. The third wire is likely a Tach Out (Tachometer Out) signal which you likely won't be using. Just a matter of getting the fan polarity correct. That would be my guess anyway.

Ron

 

It's this fan. Definitely DC and VERY quiet so I'm not concerned about noise

The wires are both solid black, no white stripe...

 

Yeah, the adapter only picks 12 VDC off the molex connectors. The third wire is the tach signal and not used.

Ron

 

Fan is 12VDC
You need to find out the positive and negative pins of the fan

 

How do I find that? The wires are not marked in any way that differentiates them and neither are either end of the adaptor. That aside, the molex connector is labeled 1,2,3 and 4 on each pin but that's it.

 

Modern small DC fans are actually BLDC with a fail sensor.
The sensor output can be ignored where just DC supply is available and no failure circuit is present.
In some cases the paper cover can be pried back and disclose the terminations and if you are lucky you can identify the + &- DC.
Max.

 

Bummer, just pried it up and one side was solid plastic and the other didn't allow a view of the terminations. Could I simply touch the wires to the outputs to find out since its such low current or would that be a bad idea even on this small scale?

 

If it is any help, the sensor is generally an outside conductor on the connector, so by trying the centre and an outside in turn should be OK.
Max.

 

How do I find that? The wires are not marked in any way that differentiates them and neither are either end of the adaptor. That aside, the molex connector is labeled 1,2,3 and 4 on each pin but that's it.

The two center pins on the 4 pin molex are Ground. One outside pin is 12 V and the other is 5 V. Your fan adapter only goes to a Ground and 12 V pin. Look at the adapter and note which of the two black wires goes to the outside pin of the molex. Should be Pin 1 of the 4 pin molex. Pin 1 is 12 V, pins 2&3 are Ground and pin 4 is 5 Volts. On the small connector for the fan, pin 1 should be Ground, pin 2 is 12 Volts and Pin 3 would be the unused RPM Tach Signal.

Ron

 

May be you can trace the polarity looking at the Molex connector ( if the molex wires are according to standard )
Or use the DMM to check the voltage and confirm molex connection

 

before you hack the plug off, the two black wires will go to the ground and 12v terminals on the four pin molex, so you can work out the pos and neg, chances are it will run backwards or not at all if wired reversed.

 

If it is any help, the sensor is generally an outside conductor on the connector, so by trying the centre and an outside in turn should be OK.
Max.

The two center pins on the 4 pin molex are Ground. One outside pin is 12 V and the other is 5 V. Your fan adapter only goes to a Ground and 12 V pin. Look at the adapter and note which of the two black wires goes to the outside pin of the molex. Should be Pin 1 of the 4 pin molex. Pin 1 is 12 V, pins 2&3 are Ground and pin 4 is 5 Volts. On the small connector for the fan, pin 1 should be Ground, pin 2 is 12 Volts and Pin 3 would be the unused RPM Tach Signal.

Ron

May be you can trace the polarity looking at the Molex connector ( if the molex wires are according to standard )
Or use the DMM to check the voltage and confirm molex connection

before you hack the plug off, the two black wires will go to the ground and 12v terminals on the four pin molex, so you can work out the pos and neg, chances are it will run backwards or not at all if wired reversed.

Thank you all SO MUCH! Going off the molex that way gets the polarity all figured out all the way back to the fan. You guys are great!