Do you have any idea how close to death you were? Not because your parts were wearing out (but we'll get to that), but because of your RAPIDLY declining SAF (Spousal Acceptance Factor)? I've made excuse after excuse for you to the detriment of my marriage. All for the pursuit of The Good Ice™.
For now, with some new bearings, and a new capacitor, you live and make ice. Do not piss my wife off again. Or I'll let her replace you with a wine chiller or mixing stand.
Your Benevolent Overlord.
As funny as it is for such simple parts to cause such issue, there's a whole saga attached. To skip the story: click here
I've got a Scotsman SCN-60 Pellet Ice Maker. Actually, at one point I had two.
I got my first one for ~$100 while on vacation in Florida and brought it home. The diagnosis from the previous owner: "It doesn't make ice. I don't know why."
I'm always down for an adventure, and the price seemed right, how bad could the parts be to replace?
Turns out, this first ice maker had never been serviced. And as such, had built up such a scale on the auger, that it scored both the auger and the condenser.
The parts to replace: A staggering $1400. Not including refrigeration labor.
So I started saving nickles and keeping my eye out on the marketplaces.
Weeks passed. The seasons changed. Children grew. I aged.
Finally, after 2 solid years. I had $3.47 saved. But there was a second SCN-60 local to me that popped up. Free was the asking price. $20 to hold it til I got there later in the week. It too was broken. "It doesn't make ice. I don't know why". A recurring theme.
I had hoped that it was also broken, but in a different way, and that I could Frankenstein the two together.
Fortunately for me, and the dwindling SAF, this was the case.
The motor on the second one was shot, but the auger and condenser were not.
Swap the motor and gearbox in and everything hums along. Until....
About 8 months later, it stopped keeping up in making ice. And then it wasn't making but three little pellets at a time. SAF was in freefall. Amazon wishlists were being made. Something must be done to preserve the limitless source of perfect margarita ice.
Through bottom feeding on Facebook Marketplace, I happened across refrigeration equipment that would let me test the system. I figured no ice meant it wasn't getting cold enough.
Nope, drain and refill the proper amount of R134a (same stuff you get at the car parts store), and still no ice.
When the rest of my family went out on vacation, I started to really diagnose things.
The auger motor would only run for a short time. The auger motor would get really hot. The auger motor would consume 1.3 amps before shutting down.
Consulting the manual, overcurrent protection was a thing, but not indicated anywhere on the control panel. Thanks Scotsman...
I pulled off the capacitor, and tested it on my trusty multimeter. 3.4uF, supposed to be 7.5uF. Well that won't work. In a AC motor, the run capacitor acts as a current limiter as well as part of the coil excitation. If the capacitance is too low, the motor will draw too many amps and create a bunch of waste heat.
This is in line with the motor getting hot, so a replacement was procured and pressed into service.
Partial success! We have (some) ice!
But it still trips overcurrent, and is still quite warm. There must be something inside.
Fortunately, the hoard provides, and I have a cadaver motor to examine. Because I'm sure as shit not paying $1300 for a new motor assembly.
Upon examination, I see four things.
1) An absolutely destroyed stator.
2) A truly staggering amount of corrosion.
3) A bearing sitting on top of the shaft.
4) A case that splits in half.
Upon examination of the bearing, it reads "608Z". Plug that into the google machine and we find that's exactly the bearing size used on skateboards.
The other bearing (in the housing) is stuck fast, and I can't get the shaft out.
After much swearing, drilling of fasteners, and beatings with one of many trusted hammers, the case opens.
Only to reveal nothing but corrosion is holding the shaft to the bearing. The bearing is not removed from the housing in one piece. Examination of the now freed shaft indicates the top and bottom bearings aren't the same. This one seems to have a 9.5mm ID (good luck finding that).
I have a hunch to just pull the shaft from icemaker #2 (upstairs languishing). Fortunately the bearing comes out on the shaft and isn't stuck in the housing.
This one is a different size from the lower bearing on the first motor assembly, BUT it matches the top bearing which is our old friend 608Z.
I had managed to squeeze some nice (enough) skateboard bearings onto an overnight Amazon order the night before this discovery.
A quick dremeling off of the old bearings, and putting the new ones on (through a mix of freezers, deep sockets, bench vices, and a hammer) and we reassemble our icemaker.
The motor now runs VERY cool, and for a longer period than I've ever heard before. The ice now floweth.
So. To get a $4500 ice maker for under $200, you will probably need: two broken icemakers of the same model, a 7.5uF capacitor, some skateboard bearings, and about $500 in tools.
We'll see if the repair fixes the SAF as much as it does the icemaker.
After a further 6 months of the new bearings churning away and overheating the motor again and again and again (on for a few minutes, then off for 4 to cool down), I've determined that Scotsman flew too close to the sun and damaged the SAF and tranquility of my home. The unit was unplugged and off for most of the summer.
In order to rule out the only working stator I have, I had to be even more patient. The motor/gearbox assembly new was almost $1700, and again, I'm a cheap bastard.
Finally, one day in June, my patience paid off and a new Bison 1/20HP 110V AC Offset gearmotor assembly appeared on eBay for a song. ~$100 if memory serves. The catch? It came with a different output shaft design, and a different gear ratio (lower speed, 3x the torque).
After it arrived, I disassembled the brand new (seriously, still sealed) gearmotor and extracted the output shaft.
I whipped up the existing output shaft (from the long deceased gearbox) in FreeCAD, as well as the new eBay output shaft. I started comparing dimensions and found the two to be nearly identical. See attached github link for the files to see for yourself.
The most notable difference is the original gearbox had an output gear about half the thickness as the output gear on the eBay gearbox.
After consulting the mechanical engineers at $DAYJOB, it was determined the correct course of action after some hasty napkin math was to Full Send.
One swapped output shaft, a gearbox transplant, and some prettying up of wiring later, and a much slower ice machine is drawing 1/2 the current while chruning out copious amounts of ice.
Total bill so far:
|Mechanical Engineering Advice
|$20 (cost of a favored 6-pack)
Was it worth it? I'm not sure. But for now, I can have an ice cold drink with ice to crunch whenever I'd like.
The ice floweth freely. There is peace in the kingdom.