Salvaging a Caframo fan with a failed control board

[Tin Tin]

The only caution I would have on this is the cheap controller boards possibly with no conformal coating, so subject to salt air corrosion in time, overheating, and blowing the fuse...... hopefully.

[GILow]

Originally Posted by Tin Tin

The only caution I would have on this is the cheap controller boards possibly with no conformal coating, so subject to salt air corrosion in time, overheating, and blowing the fuse...... hopefully.

Good point. Isn’t there some kind of spray I could use?

[NevilleCat]

Originally Posted by GILow

Good point. Isn’t there some kind of spray I could use?

Maybe this? https://www.jaycar.com.au/circuit-bo...y-can/p/NA1002
There are probably better coatings out there but hard to find in Aus

[GILow]

Originally Posted by NevilleCat

Maybe this? https://www.jaycar.com.au/circuit-bo...y-can/p/NA1002

There are probably better coatings out there but hard to find in Aus

Thank you, great find as I drive past Jaycar regularly. I’ll grab some, I think Tin Tin made a good point.

[GILow]

Ye gods! I just noticed these fans are going for AU$219.95 each at Whitworths! I don’t remember paying that much for my other three.

[Lake-Effect]

Originally Posted by GILow

Hi all,

A few months back I noticed four Caframo 12 volt fans in the dumpster at the marina....

So, after a discussion here on CF I finally got around to ordering some PWM DC motor controllers on EBay @ AU$2.45 each.

I chose the sort with the rotating knob that doubles as an on/off switch

I have nothing but respect for someone who can pick up something that someone else has tossed and make it work again . It's a bit of an obsession with me sometimes...

So, please confirm: the controllers were/are just for speed regulation, and if you connected 12v directly to the two leads coming from the fan motor, it would run at full speed?

I bought 10 of that same PWM controller for experiments with LED dimming. i should probably also try it on a fan as well...

PS - re conformal coatings - there are several sprays, including Boeshield T9. But one coating that's effective but too often overlooked is paraffin wax. Melt about 1/2" of wax in a small saucepan, and dip the board in... let cool. Great protection, and it can be mostly removed with a heat gun.

[wsmurdoch]

I just ordered what I think is the same PWM motor controller from ebay. https://www.ebay.com/itm/3-35V-12V-2...72.m2749.l2649

I have a three position switch on my failed Caframo fan. The switch has the positions off, slow (with a 33 ohm resistor in series with the fan motor), and full on. I'll make it into a rainy day science project to see if power losses in the motor controller when off ( "Quiescent current: 0.015A (standby state)" ) and at full speed (due to its efficiency) outweigh the losses when operated with the switch at half speed with the 33 ohm resistor in series with the fan motor.

US$3.79 for an afternoon's entertainment.

Bill

[GILow]

Originally Posted by Lake-Effect

I have nothing but respect for someone who can pick up something that someone else has tossed and make it work again . It's a bit of an obsession with me sometimes...

So, please confirm: the controllers were/are just for speed regulation, and if you connected 12v directly to the two leads coming from the fan motor, it would run at full speed?

I bought 10 of that same PWM controller for experiments with LED dimming. i should probably also try it on a fan as well...

PS - re conformal coatings - there are several sprays, including Boeshield T9. But one coating that's effective but too often overlooked is paraffin wax. Melt about 1/2" of wax in a small saucepan, and dip the board in... let cool. Great protection, and it can be mostly removed with a heat gun.

Great tip about the wax.

Yes, connecting the red and black straight to 12 volts runs the fan at the “normal” full speed, so the original control boards just provided the two lower speeds, and in some models, the timer function.

[GILow]

Originally Posted by wsmurdoch

...

US$3.79 for an afternoon's entertainment.

Bill

It will be good to hear the efficiency results... but... US$3.79 is a bit extravagant. [emoji846]

Jokes aside, I just bought four more and was a bit peeved that they cost me AU$14.45, until I realised that postage was free, whereas I’d paid $11 postage on the previous five, so they were actually cheaper. But it did mean I’ve actually understated the real cost of the controllers in my original post. [emoji53]

[wsmurdoch]

Check my ebay link in #22. The US$3.79 includes the shipping and China is closer to you than me. It is almost a record for a promised afternoon's entertainment, but I once did better.

Years ago, I stopped at a Salvation Army thrift store and found a Singer 403A sewing machine covered in dust, dumped in a wood peach crate, and marked $5. Everything was there; all the parts, a complete set of stitch disks, even the manual and sales receipt. I bought it, brought it home, and spent three or four days cleaning it up, flushing out the dried oil, adjusting it, and replacing the dried and cracked wiring. My wife complained mightily about "that piece of junk", waste of time, and such. But, she had just spent $5 on a movie DVD rental that only lasted 90 minutes. My entertainment lasted days. I gave the repaired machine to our older daughter who still uses it today. I felt badly about only paying the Salvation Army $5, so I did a little price checking on ebay and put the difference in their Christmas kettle. It beats watching the TV.

Bill

[wingssail]

Originally Posted by Draughty

Yeah Caframo fans; great design, pity about the execution.

There's a few marine equipment companies around that reckon design is everything (think Crewsaver; who promote an inflatable lifejacket/harness with a dedicated PLB pocket which won't fit any PLB available in the world).
Testing is everything!

Rgds all.

Great Design? Ha, it looks like a circus.

I prefer my Hella Turbos, but they have problems too. However we have 7 installed and 2 spares.

[Happydrv]

Here is the finished product. I would recommend putting the hole more centered lengthwise. I wanted to avoid the power wires and ended up bumping against the side as it narrows off center. Can't redrill without making an ugly mess....
Works great and saves a fan, now well over $100 on sale.

[svmatilda]

Gday Mate, I see its been a couple of years since you did the upgrade/repair to those fans, can you tell me how they are performing. I did something similar to 2 fans a few years back where I installed PWM boards, I thought we were on to a good thing but unfortunately the motors burnt out after a couple of nights . I am wondering if I should give it a go again or just dump the fan thats not working, be interested to hear how your repaired fans are going.

[GILow]

Originally Posted by svmatilda

Gday Mate, I see its been a couple of years since you did the upgrade/repair to those fans, can you tell me how they are performing. I did something similar to 2 fans a few years back where I installed PWM boards, I thought we were on to a good thing but unfortunately the motors burnt out after a couple of nights . I am wondering if I should give it a go again or just dump the fan thats not working, be interested to hear how your repaired fans are going.

They are all still working perfectly. And some, like the bedroom fans, are left running for days or even weeks at a time over summer.

I’m intrigued that yours burnt out. Were they Caframo fans?

[svmatilda]

Yes they were both Caframo Sirocco fans, and looking back we only got 1 or 2 nights run time out of them after installing the PWM controllers. It did make me wonder at the time whether the original electronics ran the fan at a slightly lower voltage. I have a friend who went down the resistor route and his work ok. So I can only guess the reasons my fans originaly played up was because the motors were failing.

I am about to install another PWM controller in a fan that runs ok when we can get the electronics running,,,,, lets see how that goes.

Thanks