Changing voltages.

[Spork Schivago]

Re: Changing voltages.

Even though the model numbers matched, the sticker and connector were different. I found the one that has the same sticker and same 5-pin connector as the one I have. This is the exact same one, it looks the same, all the numbers match, everything. Ignore the previous one:

http://www.amazon.com/NMB-MAT-4715KL.../dp/B0099W7O40

[stj]

Re: Changing voltages.

129CFM!!!!!
damn i want one!
http://www.nmbtc.com/fans/part-numbe...L-04W-B56/5267

just so you know, a "good" fan is usually about 80CFM and a cheap crappy one is high 30's

[dmill89]

Re: Changing voltages.

No, it is not. It has 7-blades and it's made by Minebea-Matsushita. I have a few of these types. They're in a lot of the older Dells I have. Here's a link to the one I have (but mine doesn't have that grill that the one here has).

https://www.dreamhardware.com/fan-5w...FckehgodduMEug

Even though the one I linked to uses the same amperage (1.30amp), for some reason, it has the standard three-pin header it looks like, instead of the Dell custom 5-pin.

I bet a lot of people are probably upset after buying that. They probably thought like I thought, that it could just be plugged into the motherboards header. Drawing the 1.30amp probably ruined their board.

The one in my PowerEdge 840 is the even higher amperage 2.5A Matsushita NMB-MAT Model 4715KL-04W-B86 which would be even worse for a motherboard not designed for that amperage.

[ChaosLegionnaire]

Re: Changing voltages.

yea nice 129cfm fan there, spork. i got a scythe ultra kaze 120. its also a 120x38mm fan like yours but it only uses 0.6amps @ 3000rpm to give 133cfm! was rather expensive tho. cost me US$25!

[Spork Schivago]

Re: Changing voltages.

129CFM!!!!!
damn i want one!
http://www.nmbtc.com/fans/part-numbe...L-04W-B56/5267

just so you know, a "good" fan is usually about 80CFM and a cheap crappy one is high 30's

Yeah, I think I wrote about what happened when I turned it on. It was actually on the floor the first time but it freaking moved! I was like holy cow! So I turned off the PC and carefully grabbed hold of it. Then I flicked the power switch and it was pushing papers around on the other side of the room. It's insane. You can actually feel the force in your hands when it turns on.

[Spork Schivago]

Re: Changing voltages.

The one in my PowerEdge 840 is the even higher amperage 2.5A Matsushita NMB-MAT Model 4715KL-04W-B86 which would be even worse for a motherboard not designed for that amperage.

It'd be fine if you hooked it up to one of the power supply molex connectors though, right?

What if I used the floppy drive mini-molex or whatever it is. Could that handle the current or are the wires too small there? I use an external USB floppy drive so I have a spare floppy drive mini-molex connector in my PC.

[dmill89]

Re: Changing voltages.

If you want a 120mm fan that can move a ton of air, and is compatible with most motherboard fan headers the 0.6A 103.8 CFM Matsushita NMB-MAT FBA12G12H and 0.7A 120CFM Delta AFB1212HHE-F00 are decent options, though neither is particularly quiet if that is important to you.

i got a scythe ultra kaze 120. its also a 120x38mm fan like yours but it only uses 0.6amps @ 3000rpm to give 133cfm! was rather expensive tho. cost me US$25!

Definitely has good airflow, but $25 for a sleeve bearing fan with only a 30k hr. MTBF is a bit steep.

[Spork Schivago]

Re: Changing voltages.

yea nice 129cfm fan there, spork. i got a scythe ultra kaze 120. its also a 120x38mm fan like yours but it only uses 0.6amps @ 3000rpm to give 133cfm! was rather expensive tho. cost me US$25!

Wow, that's crazy! How loud is it running at full speed? I have a few Dell here (at least 4 I believe). I'm thinking of checking the other ones to see what fans are in there when I find some time.

I figure if I can get four of these things, I can build hovercraft of helicopter out of them!

[dmill89]

Re: Changing voltages.

It'd be fine if you hooked it up to one of the power supply molex connectors though, right?

What if I used the floppy drive mini-molex or whatever it is. Could that handle the current or are the wires too small there? I use an external USB floppy drive so I have a spare floppy drive mini-molex connector in my PC.

It should be fine hooked directly up to the PSU. Of course it will run at full speed the whole time (I imagine it does this anyhow on a non-dell motherboard) but if noise isn't an issue that won't really matter.

[Spork Schivago]

Re: Changing voltages.

It should be fine hooked directly up to the PSU. Of course it will run at full speed the whole time (I imagine it does this anyhow on a non-dell motherboard) but if noise isn't an issue that won't really matter.

That takes me back to my original question. I could slow them down by wiring a bunch of resistors in series to the 12v supply, correct? I'd prefer to use one of those variable resistors, a potentiometer, to control the speed and noise a bit. I wonder how much current the average pot can handle.

[dmill89]

Re: Changing voltages.

That takes me back to my original question. I could slow them down by wiring a bunch of resistors in series to the 12v supply, correct? I'd prefer to use one of those variable resistors, a potentiometer, to control the speed and noise a bit. I wonder how much current the average pot can handle.

Yes, many fans ship with a little dongle that has a resister to slow speed and reduce noise, and the manual fan controllers that were common in the days before PWM fans (and you can still buy) were common are nothing more than potentiometers.

You could rig up your own setup, or of you want something ready-made you can buy something like one of these:
http://www.newegg.com/Product/Produc...-009-_-Product
http://www.amazon.com/Cooler-Cooling...fan+controller
http://www.amazon.com/Evercool-Twist...fan+controller

[Spork Schivago]

Re: Changing voltages.

That's cool! I like the first link. I'll probably just rig something up myself though, seeing how I have a few pots floating around here somewheres. I'll just adjust it to where I want it and probably leave it in the case. Not sure if I want the fan in the front pulling cold air in or in the back blowing hot air out. I'll probably put it in the front so it's not stealing air from the CPU fan. Also, I wouldn't have to worry so much about that pot grounding out on the case or the board.

Seeing how I more than likely have a few of these 120mm fans, maybe I should hook a couple up. One in the front, one in the back. I'm just worried it'll steal the air from the CPU fan if it's in the back there.

[ChaosLegionnaire]

Re: Changing voltages.

What if I used the floppy drive mini-molex or whatever it is. Could that handle the current or are the wires too small there?

the berg connector or 3.5" floppy drive connector cable typically uses 20awg wires compared to 18awg for the 4-pin molex connector cables and the connectors are smaller too, so it has a lower current limit. the current limit for the berg connector is 3 amps vs 8 amps or so for the molex. so dont connect more than two of those 1.6 amp fans to the berg connector. even then, its 3.2 amps total which is really pushing it, so i do not recommend it for those fans. use the molex connector instead. hot or overheating cables are NOT fun or good even if they arent melting for that matter!

Definitely has good airflow, but $25 for a sleeve bearing fan with only a 30k hr. MTBF is a bit steep.

aye, japanese stuff is often expensive and overpriced...

[Spork Schivago]

Re: Changing voltages.

the berg connector or 3.5" floppy drive connector cable typically uses 20awg wires compared to 18awg for the 4-pin molex connector cables and the connectors are smaller too, so it has a lower current limit. the current limit for the berg connector is 3 amps vs 8 amps or so for the molex. so dont connect more than two of those 1.6 amp fans to the berg connector. even then, its 3.2 amps total which is really pushing it, so i do not recommend it for those fans. use the molex connector instead. hot or overheating cables are NOT fun or good even if they arent melting for that matter!

aye, japanese stuff is often expensive and overpriced...

Thank you ChaosLegionnaire. I questioned if the smaller gauge wire would be able to handle the current or not. How did you know that the 20awg berg connector could handle 3 amps? Was there a formula you used or did you just read it somewheres? I'm asking because I think it'd be a very useful skill to have, to be able to calculate how much amperage a certain gauge wire could handle... Thanks!

[stj]

Re: Changing voltages.

there are tables for that,
https://duckduckgo.com/?q=wire+guage...t-wt&kv=1&kh=1

[Spork Schivago]

Re: Changing voltages.

there are tables for that,
https://duckduckgo.com/?q=wire+guage...t-wt&kv=1&kh=1

Thank you Stj, I was more interested in knowing the formula on how to calculate it but I think I figured it out.

Some places say 700 circular mils per amp, some say 300 circular mils per amp. From what I've been reading, there's more to it than just gauge. Temperature, what type of metal is used (copper, aluminum, etc), is it coiled together, etc, plays a roll.

So, 20 awg wire has a circular mil of 1,022 cm. 1,022 / 300 =~ 3.4 amps. I think that's where the 3 amps comes from.

Thanks!

[Spork Schivago]

Re: Changing voltages.

A quick question for users who live in countries where the metric system is the dominant measuring system. This is going a bit off topic here, but I wanted to know. Here, in the US, we have something called a mil. It's 1/1000th's of an inch. When I take something to the machine shop, they'll use mils for certain measurements. Is mil a universal thing? Or do the metric people refer to millimeters as mils? Thanks.

[stj]

Re: Changing voltages.

micron's

btw, when doing wire calculations the frequency must be taken into account because of a thing known as skin-effect.
electricity at high frequency's (50Khz+) likes to ride on the surface of the metal rather that through it.
getting an explanation for why is probaby going into "dark physics"

but put simply, if your run high frequency you need lots of small strands rather than one thick strand.
that is even more important when making transformers.

[Spork Schivago]

Re: Changing voltages.

micron's

btw, when doing wire calculations the frequency must be taken into account because of a thing known as skin-effect.
electricity at high frequency's (50Khz+) likes to ride on the surface of the metal rather that through it.
getting an explanation for why is probaby going into "dark physics"

but put simply, if your run high frequency you need lots of small strands rather than one thick strand.
that is even more important when making transformers.

Thank you Stj! I wish there was a Like button on here like some other forums have. There's a lot of times forum members answer one of my questions with an answer that I really like and would love to hit a + or like button or something.

I need to find some good free online physics resources. I never had the pleasure of taking any physics classes. I've talked to a few people who took some and that stuff sounds amazingly fun!

[ChaosLegionnaire]

Re: Changing voltages.

How did you know that the 20awg berg connector could handle 3 amps? Was there a formula you used or did you just read it somewheres?

i read about it somewhere. i remember looking at current limits for different video card power connectors.