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tnranger
super member


Reged: 01/14/12

Electrical help with cooling fan design
      #5645625 - 01/27/13 08:46 AM

I'm trying to build a cooling fan assembly for an XT10i. I have a repurposed 12 volt fan and am looking for a switch to control the fan. I would like to be able to do a high/ low/ off configuration, and wonder if this switch would work:

http://www.amazon.com/gp/product/B003AU5KPW/ref=s9_simh_gw_p263_d0_i1?pf_rd_m...

I plan on using 8 AA nicads for power.

Any help/suggestions are appreciated.


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bob71741
Pooh-Bah
*****

Reged: 02/16/08

Re: Electrical help with cooling fan design *DELETED* new [Re: tnranger]
      #5645823 - 01/27/13 11:01 AM

Post deleted by bob71741

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tnranger
super member


Reged: 01/14/12

Re: Electrical help with cooling fan design new [Re: bob71741]
      #5645946 - 01/27/13 12:16 PM

The fan does have 3 wires. (now I know why!)
Thanks for the suggestion. How would I wire to this switch?


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jerwin
scholastic sledgehammer
*****

Reged: 05/17/12

Loc: Romeoville IL
Re: Electrical help with cooling fan design new [Re: tnranger]
      #5646321 - 01/27/13 04:07 PM Attachment (16 downloads)

I didn't do a high low switch in mine but this is my wiring diagram.

This is what mine ended up looking like when completed. I used a coiled phone cable that I pumped the power over so I could leave the power supply on the ground rather than attach it to the OTA. I've also revisited the design to add a cap over the switch so I know it's turned off when transporting.

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5502411/Main...

Good luck.
Jim


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tnranger
super member


Reged: 01/14/12

Re: Electrical help with cooling fan design new [Re: jerwin]
      #5646385 - 01/27/13 04:33 PM

Thanks, Jim. Your set up is the most elegant I've seen. I plan to use an old phone cord I have laying around. I would just like to be able to slow the fan down while I am observing, hence the 2 speed switch. BTW, shouldn't there be another wire coming from the fan?

Edited by tnranger (01/27/13 04:37 PM)


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jerwin
scholastic sledgehammer
*****

Reged: 05/17/12

Loc: Romeoville IL
Re: Electrical help with cooling fan design new [Re: tnranger]
      #5646478 - 01/27/13 05:20 PM

Thanks, I did make one later modification that I didn't list in that post. I replaced the machine screws in the mirror cell with longer screws (had to special order them) but that let me attach the fan and plastic cover to the ota a lot easier than with the stock screws that where just barely long enough.

My fan does have 3 wires coming out of it, I just never knew what the 3rd wire was for. I typically leave my fan running when viewing and I don't see any vibration which I'm sure is what you're trying to avoid with the dual speed.

I've seen some fans that have a switch built into them for speed.
http://www.amazon.com/Antec-TriCool-120mm-Red-LED/dp/B00066FH7O/ref=sr_1_7?ie...

I just don't know how to wire that into a homemade switch (which is what your original question was about)

Wish I could be more help, I'm just not electrically inclined enough to understand what does what. My only tip to you is to draw it out as you experiment because I probably couldn't have put it back together properly once I moved it from the test table to the install table.

Jim


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Gene7
scholastic sledgehammer


Reged: 06/10/10

Loc: Mid Ohio, USA
Re: Electrical help with cooling fan design new [Re: jerwin]
      #5646655 - 01/27/13 06:38 PM

8 rechargeables, Naaa, that is a lot of grief. Use 3 4 volt lithium rechargeable cell # 18650, a much better battery. Get special size cell holder from e-bay. Use special lithium charger. Cells will hold a charge for a year. Not expensive now. Gene

Edited by Gene7 (01/27/13 06:41 PM)


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tnranger
super member


Reged: 01/14/12

Re: Electrical help with cooling fan design new [Re: Gene7]
      #5646751 - 01/27/13 07:24 PM

I appreciate the tip Gene.

I'm trying to make use of the 20 or so rechargeable energizers we have in circulation in the house now, but will check the lithium batteries out.


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wirenut
Pooh-Bah


Reged: 09/21/06

Loc: m'dale Pa
Re: Electrical help with cooling fan design new [Re: jerwin]
      #5647887 - 01/28/13 11:33 AM

Quote:

I didn't do a high low switch in mine but this is my wiring diagram.

This is what mine ended up looking like when completed. I used a coiled phone cable that I pumped the power over so I could leave the power supply on the ground rather than attach it to the OTA. I've also revisited the design to add a cap over the switch so I know it's turned off when transporting.

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5502411/Main...

Good luck.
Jim


something doesnt look right in this drawing. when the switch connects the battery feed to the wire on the left side, it should be shorting out battery. thinking about it, if its a potentometer and not just a switch it would work fine but would need to be sized to motor.
the speed switch in our cars heaters are wired so high goes straight to the fan, medium goes thru a resistor then to fan,low goes thru a bigger resistor then to fan. the resistor arent part of the switch they are located in the cars duckwork to help keep them cool and not part of the switch. this might be how you snowmobile switch be intended to work.


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tnranger
super member


Reged: 01/14/12

Re: Electrical help with cooling fan design new [Re: wirenut]
      #5648460 - 01/28/13 03:17 PM

That is my concern.
Would I be better off to get a cheap potentiometer and forget the switch in my original post? Remembering this fan has 3 wires, how would I wire a 3 post pot in this circuit?


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gpelf
sage


Reged: 12/28/11

Loc: Kentucky
Re: Electrical help with cooling fan design new [Re: tnranger]
      #5648509 - 01/28/13 03:33 PM

If the 3rd wire is yellow it may be from a PC, In which case the wire is used to monitor the fan speed and not a secondary speed line......

Clear Skies,
Greg


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tnranger
super member


Reged: 01/14/12

Re: Electrical help with cooling fan design new [Re: gpelf]
      #5648552 - 01/28/13 03:54 PM

This is a scavenged computer fan (I forgot to mention that in my original post). If the third wire is a speed monitoring line, how would I wire this fan to control the speed?

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tnranger
super member


Reged: 01/14/12

Re: Electrical help with cooling fan design new [Re: tnranger]
      #5648934 - 01/28/13 06:39 PM

Just got home, it does indeed have a yellow lead. It is a Foxconn DS90SM-12 rated at 35 CFM and 0.18A.
Any ideas on wiring to control speed?


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Mxplx2
sage


Reged: 09/12/12

Loc: PA USA
Re: Electrical help with cooling fan design new [Re: tnranger]
      #5649086 - 01/28/13 07:50 PM

In a pinch you could experiment. First measure the resistances between all three wires. If there are no dead shorts or very low resistances, hook up 12 volts between two at a time and see what happens. Perhaps introduce a potentiometer and experiment with that.

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Gene7
scholastic sledgehammer


Reged: 06/10/10

Loc: Mid Ohio, USA
Re: Electrical help with cooling fan design new [Re: Mxplx2]
      #5649162 - 01/28/13 08:17 PM

Yes, forget the third wire and control the power with a Buck Converter from e-bay,NOT a pot, which wastes power. The adjustable Buck converter does not, it converts excess power to amps. Costs $1.52 on the Bay. Get several. Gene
http://www.ebay.com/itm/251066005460?ssPageName=STRK:MEWAX:IT&_trksid=p39...


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gpelf
sage


Reged: 12/28/11

Loc: Kentucky
Re: Electrical help with cooling fan design new [Re: Gene7]
      #5649260 - 01/28/13 09:04 PM

I hate to be a Naysayer, But.....
The yellow line cant be used for speed control, It is hooked to a hall sensor that produces a square wave on this line when a very small magnet on the motor armature spins (This is how the computer monitors the speed). I use one of the true DC fans (NO small circuit board under sticker and frame) and for a second reason, I use a DPDT center off switch and a variable supply. This way I can adjust to any speed and Reverse the fan as well. Hope this helps some.
The buck converter mentioned by Gene7 is also a very good idea if you dont care about reverse.


Good Luck,
Greg


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Mark Peterman
super member


Reged: 08/07/12

Loc: Texas
Re: Electrical help with cooling fan design new [Re: gpelf]
      #5649434 - 01/28/13 10:58 PM

Greg,

Do you have a make/model or part number for that fan you use? I can't find any that are reversable.


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gpelf
sage


Reged: 12/28/11

Loc: Kentucky
Re: Electrical help with cooling fan design new [Re: Mark Peterman]
      #5649852 - 01/29/13 08:35 AM

Mark,

Not sure if they make a small modern fan that will, The one I use came out of an old circa 1970`s oscilloscope. I will be glad to look in my garage and see if I have another.

Clear Skies,
Greg


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gpelf
sage


Reged: 12/28/11

Loc: Kentucky
Re: Electrical help with cooling fan design new [Re: gpelf]
      #5649856 - 01/29/13 08:40 AM

Found one here, but i`m not sure about the availability.
Link

Greg


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Mark Peterman
super member


Reged: 08/07/12

Loc: Texas
Re: Electrical help with cooling fan design new [Re: gpelf]
      #5649899 - 01/29/13 09:16 AM

Thanks Greg, I appreciate the help.

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