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Things, sometimes [work equipment]

The lab here has two nice-looking Percival incubators. Unfortunately, at some point early in their usage, they were filled too full with crickets, and this started to cause a buildup of material on the unit cooler fan motors. The buildup, in turn, wore out the fans to the point where they started making horrible fan-dying noises. Before I arrived, at least some of the fans were replaced, but of course I don't know which out of the four fans (two fans per unit). About a week ago, I turned on the second incubator, and left it running without any crickets in it whatsoever. Over the weekend, one of its fans started to make the terrible dying noises.

It sounds like we're probably out of the warranty period for the units, and in any case, the person I tried to contact at the original vendor hasn't replied to my query, so I'm strongly inclined to figure out how to fix/replace the damn things myself.

But ugh, I don't know a whole lot about fan motor specs, so it's taking some head-scratching to try and figure out what to order/stockpile as a replacement. One of the fans helpfully declares, on its side, "120 VAC 60 Hz S1 0.45 A" and it has a 1/8" shaft diameter with a 1.5" shaft. From this I gather that it's for a 120-voltage system (US standard), operates at 60 Hertz (i.e. 3600 rpm) with a current of 0.45 amps (specs from the wiring diagram indicate the cooling unit has a total current of 1.3 amps).

So, does that mean that this will work? Or will it draw too much current? The last time I thought about most of this was high school physics, argdarnit.

Another diagram describes the whole cooler unit as "RCO-001 UNIT COOLER BOHN #TA-17SF; w/TWO(2) 115 VAC/1-PHASE/60 Hz, 1.6 TOTAL FLA, 210 TOTAL CFM FANS; 1/2 SAE FLARE NUT INLET, 3/8 ODF SOLDER SUCTION-LINE CONNECTION, 1/2 ODF SOLDER DRAIN-LINE CONNECTION"

More information needed?


( 14 remarks — Remark )
Mar. 9th, 2016 02:09 am (UTC)
Nothing particularly useful (I am sleep deprived at the moment) except for the idle comment that the last two times I was replacing failing fans in non computer things, it turned out that standard 10cm (I think?) computer case fans were pretty much just the thing. (After the first one - which was in our chillers - I got a stack of them, so the second time I just grabbed one to see if it might work, and sure enough.) Are you fairly certain you need to replace just the motor, and not the whole fan?
Mar. 9th, 2016 02:10 am (UTC)
Could you take a picture of what you currently have?
Muffin fans like this:
are ubiquitous in electronics.
Yours is a monster: that's a 50 watt fan.
Probably the most relevant item in the latter chunk of info is 210 total cfm -- that's the cubic feet per minute it flows. I presume that's several fans, some of which are burnt out or failing?
Two of these: http://www.amazon.com/dp/B009OWRMZ6 would exceed the flow capacity of the originals. They should also last for something like five years of continuous usage.
The Packard frame motor would probably work. Generally you'd rather the replacement have the same or slightly lower max amperage, because that way the power supply/control system wouldn't be straining to run it.
Mar. 9th, 2016 02:40 am (UTC)
Photos, as requested:
Incubator fan

Incubator fan

And yeah, these are monsters because they're doing a lot of work to ensure even airflow through an environmental chamber that's slightly larger than a refrigerator. Do you think muffin fans would do a better job of coping with dust and debris as compared to the shaded pole style?
Mar. 9th, 2016 02:41 am (UTC)
The overwhelming ubiquity of FST rulers!
Mar. 9th, 2016 02:43 am (UTC)
I know, right? I have an inordinate fondness for this kind of ruler. In the present case, it was the closest thing within reach for providing a sense of scale. It isn't a scientific photo if there isn't a scale. ;^)
Mar. 9th, 2016 02:44 am (UTC)
And also - it might be more straightforward to just replace the whole fan, you're correct. It kind of pisses me off that these fans have failed and are supposedly "expensive to replace." Incubators are a pain in the ass.
Mar. 9th, 2016 02:52 am (UTC)
Weird proprietary parts streams. There are a lot of things that have that kind of ecosystem.

(And a lot of the them can be kludged, and... then you get to decide how much your time is worth versus the ridiculous amount of money you can save. There are way too many things around the lab that it is known that I can fix - like the non user serviceable hydraulic micro manipulators, for one of the more amusing examples - but then, I had it in the back of my head that if my health didn't improve enough to really make a proper go at research, I could be the best lab manager ever.)
Mar. 9th, 2016 02:44 am (UTC)
The main difference is quality muffin fans have ball bearings, while almost all the shaded pole ones have sleeve bearings, which don't last as long. (ball bearings have better seals and lower wear even when the seals are shot.)
But those are huge. The ones I was posting would give you a 130 mm wide blast of so much air they'll lift themselves off the table: a laser blast. Yours are probably more like 400mm in diameter. So, yeah, replacement of the motor is probably a better idea. Then it's a matter of trying to figure out how to bodge together a connection between the motor case and the bracket that attaches to the whole contraption. (Presuming the shaft size is the same. If you have a smaller shaft on your replacement motor I can cut a bushing that'll take up the difference, very easily.)
Mar. 9th, 2016 02:46 am (UTC)
Oh hey yeah ruler. Okay so that's like 160mm blade tip to tip. Let me look around a bit.
Mar. 9th, 2016 02:49 am (UTC)
http://www.amazon.com/115V-AC-Cooling-172mm-150mm/dp/B005F1MX54 is 150mm in diameter and may do what you need for a fairly reasonable price. It's not quiet, but boy will it move a lot of air. If there is no speed controller/thermostat, you could use a wall dimmer to slow this down a bit and reduce the noise a lot.
Mar. 9th, 2016 02:51 am (UTC)
btw volts times amps is watts, so you have 120*0.45 = roughly 55 watts. Anything in the 40-60W range should be okay, especially if it's in the same flow rate.
Mar. 9th, 2016 03:01 am (UTC)
Good to know about the difference between bearing types. That definitely pushes me in the direction of muffin fans. I'll need to put together some info for my boss on this, but I think she'd be amenable to the switch. It sounds like the first round of replacements was expensive, but that was probably because she had the original company do the work (and WHY don't they sell parts??!! Jerks.)
Mar. 9th, 2016 03:06 am (UTC)
If she feels like moving to muffin fans, one of several nice things is that in the future they will be trivial to replace.
( 14 remarks — Remark )

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