Replace, repair, or upgrade motors in Cafromo 747 fans? Brushless an option?

[autumnbreeze27]

We loaded the boat up with Cafromo 747 fans... the cageless ones.

We had our first one grenade on us a few months ago. Several others are sounding like they are moments away from self destruction.

I pulled the one apart that had died, and the motor appears to be a rs-555sh20120 (barely legible on the motor)

Should I take the bad motor to somebody in La Paz and have the brushes replaced? or should I buy new motors? can I get a better motor? maybe brushless? without getting louder or drawing more power?

All my google mojo can find is a link to DC Motors | All Electronics Corp.
Mabuchi# RS555PH-23300A

So the model # is slightly off... but I was wondering if anybody on here had any experience with these and had any info to share.

Thanks!

[tkeithlu]

Well, I think you can eliminate repair as an option on a $4.50 motor. What's the cost of the fan? Is it worth ordering a few spare motors to substitute in when one blows?

In all likelihood the motor self destructed because of a bad bearing, perhaps in turn due to a fan not being perfectly balanced. It could also blow if it really isn't big enough to power your fan blades. That's an awfully small motor for a ventilation fan. We use a 12v reversible fan mounted in the forward hatch - under most conditions (anchor) the natural flow is bow to stern, and we help it along by blowing inward. But, it can be reversed if the flow is stern to bow. I wish I could cite the maker, but a quick Google says there are a lot on the market. They all have considerably larger motors than yours, which might be the core of your problem.

[autumnbreeze27]

If that $4.50 motor works I'd order 10 so I had plenty of spares, I think we have 6 on the boat. It looks like if I order 10 they're only $4.

I probably paid around $40/ea for the fans. But I'm cruising full time in Mexico so I can't easily get a replacement, and if I did they'd be way more money because they charge huge import tariffs on everything gringos use.

[tkeithlu]

It sounds like you're using them for "blow on me" cooling rather than whole boat ventilation. Staying in country, consider looking at three other possibilities - computer fans (very small), truck cab fans (bigger, often cheap), and automotive radiator fans. The latter can be found at junk yard prices, and are powerful enough to flow air through your boat. We have a truck cab fan in our closed wheelhouse that blows directly on the helmsman.

[zeehag]

hay autumnbreeze--if you have a spare--mebbe we could meet up and help fix my dead one?? i only have 1.
reward to be issued for assistance in htis......<3

[Brewgyver]

The Mabuchi motor you mentioned draws 1.25 amps, the Caframo 747 two speed draws less than half that, so it's not the same motor.
Go to the Mabuchi site and look through the product sheets:
List1 : Motor Designations (alphabetical) | MABUCHI MOTOR
You won't find either of the numbers you listed, but those numbers are likely OEM numbers for specific manufacturers, and may in fact be the same motors listed under a different number on the Mabuchi site.

Compare the voltage range and current draw of each to the Caframo specs. It would appear the 545PH is pretty close,
RS-545PH

I've not seen that fan, but I've used lots of small DC motors in hobby robotics. Typical small DC "tin can" motors mount via two holes at the shaft end of the motor.Check that the physical dimensions match, specifically the shaft diameter, max overall length, max diameter, and the size and spread of the mounting holes.

[slowpoker]

Most fans, anywhere, whether the 110V AC at home or 12 Volt DC, or anything with a spinning shaft on a bronze bearing, needs cleaning and lubrication sometime or another.
Unless the electrical parts are burned, corroded or broken, any of those spinning shaft fans can be made to work again, for another year or so each time, by just cleaning off the dust and gunk even with water hose pressure and then apply a few drops of machine oil, ( not engine oil which has 'detergents' in it ) such as "3 in 1" brand sewing machine oil or thin non-detergent oil, to those bearings. WD 40 has no lasting lubrication qualities in these cases.
If difficult to place those drops of oil only to the bearing without making a mess or disassembling the unit, you can 'guide' the drops via a toothpick or a thin wire resting right on the place you need to lube and let the oil drops follow down that wire.
Don't worry about getting fresh water anywhere on the electrical parts, just let it dry before putting power to test it. I do this regularly with great results.

[autumnbreeze27]

Thanks for the lead on the rs-545ph and advice on cleaning. I have been lubing them regularly. I don't know why they die, I guess I'll find out if I open up the dead one. Maybe I'll dry washing it first, not much to lose, but I'm guessing it needs new brushes. I'll probably have to find someplace in la paz to get some brushes and try and repair them myself. The only luck I've had so far finding rs-545ph is on ebay for $20/ea.

[andyalford]

Originally Posted by autumnbreeze27

Thanks for the lead on the rs-545ph and advice on cleaning. I have been lubing them regularly. I don't know why they die, I guess I'll find out if I open up the dead one. Maybe I'll dry washing it first, not much to lose, but I'm guessing it needs new brushes. I'll probably have to find someplace in la paz to get some brushes and try and repair them myself. The only luck I've had so far finding rs-545ph is on ebay for $20/ea.

Did you have any luck with this? I really like the Caframo 747/757 fans ut so frustrated with how often they need replacing. Some are running 24 hours and rarely last 12 months.


I have had some good experience with a PWM controller on one, and wonder if this might keep it lasting longer.


Of course, to change the motor to a brushless type would be the ideal solution.


Anyone had any success with this?

[apexio]

I also was tired of replacing these great fans just because the tiny brushed motors' brushes would wear out - what a waste of money and earths resources!

I like to leave the fans running for air circulation in the tropics whenever I am off my boat (sometimes many months at a time). I have one running 24/7 on low for over a year in my cats litter box room. I have replaced the cheap brushed motors in 747 fans with brushless motors and they now run forever.

The motor I used is:
"NIDEC 22H051F PWM 12V 24V Brushless DC Motor CW BLDC High Torque Built-in Driver" I bought them on ebay for $12 each.

They are nearly drop in replacements. The only difference is mounting - I found it easiest to drill two holes behind the fan blades and use metric bolts through the plastic housing and into the motor.

With these motors, the fan is slightly slower at both speeds. The means Low is almost silent and High is not very loud.

Quieter, less power draw, will now last forever.