Help! Vintage Sears A/C fan weak/inoperative!

[red_october]

Well I just got my Sears AC and the fan was VERY weak at first and now seems to have conked out entirely. The compressor will kick over (without so much as dimming the lamps) and make VERY cold air; but the fan won't turn quickly. I got it to run weakly by giving it a kick-start with a pencil, but it didn't work long and now won't move. What do I do! I'm very happy the compressor works but that doesn't mean much without a fan!!! Thanks in advance for any and all help!

 

[sudsmaster]

If the fan motor has an oiling fitting, then perhaps it needs some oil. 20 weight oil generally works. Otherwise the fan motor might need to be replaced.

 

[coldspot66]

Most a/c's have a start capacitor wired to the fan & compressor. You can test the capacitor with an ohmmeter on the side where the fan is wired. Is the fan blade bound up, or does it turn freely? If it's bound up, you may need a new fan motor.

 

[red_october]

Turns freely. Will keep turning from momentum. If kicked over manually with a suitable instrument, it will turn for quite a while, sometimes, seemingly under power. Sometimes not. Because airflow is very low, the compressor will not run for long. But when the compressor runs, the air it makes is VERY cold.

 

[red_october]

Updates...

The motor doesn't seem to want to start on its own any more.
I have a thing of 20-weight oil designed for motors 1/4 HP and above. I can see said motor through the side grill. How would I get to it to oil it and where would I put said oil if no oil wick makes itself obvious. when current is applied to the motor it will hum a little bit as if it were under a load. Based on my experience with vintage electric fans, I am giving it every opportunity to catch and run. It may be my imagination but it seems to be turning slightly faster.

 

[sudsmaster]

Many 110 volt motors have capacitors that provide starting current to the starting winding in the motor. Once the motor gets up to a certain speed, a centrifugal switch shuts off the starting winding and the main winding takes over to keep the motor turning.

Failure to start can be due to a faulty capacitor. Failure to run after starting could be bad bearings or bad wiring in the winding. Maybe a loose connection to the motor or in the switch. I suspect you'll have to open the thing up one way or another to get at the motor and switches to find out.

 

[danemodsandy]

Capacitor or Gummy Lube

Red:

Once you get the unit open, see if the construction of the fan motor is such that you can get the nozzle of a can of WD-40 close to the bearings. I'd shoot the bearings with WD-40, turn the fan a bit by hand, and see if that makes the motor run. If it does, you had dried-up oil hampering the motor's operation. HOWEVER- you should remember that WD-40 is a penetrant, not a serious lubricant. If WD-40 makes the fan run, you should then oil it. On older units, there is usually an oiling hole in the motor housing, and it's usually marked. Six drops or so, while turning the fan blades by hand, will usually do the trick.

If the WD-40 trick does not work, it's likely your motor's capacitor is at fault. DO NOT attempt any repairs yourself if you are not experienced with capacitors. Capacitors store a large amount of electricity to use for "kick starting" motors, and they are "live" whether the unit is on, off, plugged in, or unplugged. They BITE, trust me; you can get injured pretty badly by one- or worse. If all this is familiar to you, my apologies for covering old territory. But if you didn't know, I don't want you to get hurt, mmkay?

 

[red_october]

Curiouser and Curiouser...

Well There is some good news on the home front: The unit, which took me and my ladyfriend (whom I might add is a very strong woman; she proudly boasts of the "Finnish peasant women" in her background) several minutes of maximum exertion to put in the window, is a bloody SLIDE OUT CHASSIS. It had no ready indication of being such and it wasn't apparent until I looked at it carefully. This answers the question of dissasembly. It is still frighteningly heavy; I will probably need a helper again to remove just the works from the shroud.

At any rate, the motor is made by GE (perhaps this answers the question of who made it for Sears) and, peculiarly, has wiring diagrams and even wires for a variety of fan speeds, although the unit has only one. All of these wires chase off into the control box (Did Sears really save all that much by omitting four positions from the switch yet having to have two seperate faceplates printed up, one for the full-function unit and one for the single-speed unit?), which I haven't yet opened.

Furthermore, when I had the unit partly slid into the room, I was reaching around on the back of the fan for an obvious oil fill, but found none (I still haven't seen the back of the fan; this does not disprove its existance). What I did find was that the motor was rather frighteningly hot; not hot enough to burn, but hotter than you'd think a 1/10th HP motor should get in operation, especially when it was doing precious little of that. Heat suggests resistance which suggests... something not right in the motor. It turns very freely, just not as quickly as it should and it will not start. I will try to oil it when I can (I will be busy all day tomorrow and it's 2:00AM right now so help is a little scarce) but it's starting to look, at least to me, like I might have to replace the motor or have it re-wound or something like that. Anyone have any thoughts? The motor doesn't seem to be remarkable, are motors for 50-year-old A/Cs available? How much is it to have a motor re-wound? Oh, and is that startup cap on the motor or the switch side of things? (for some reason I'm thinking of Toyota alternators that have integral regulators...)

 

[danemodsandy]

Can't Speak to the Cost...

...But remember- not every motor can be replaced, but most can be rewound.

I think that heat might be a good sign. If the shaft can't spin freely in the bearings, heat would be generated. That might be a sign that gummy old oil is the culprit. You'll know more later when you get to try the WD-40 trick, I guess.

Best of luck- I know what it's like to own a gorgeous vintage machine and have it give frustrating problems at first. With me, it was my Volvo 240 wagon.

 

[red_october]

I could go on...

Sitting outside right now are a 1984 Corvette and a 1988 MR2. I have a thing for pretty, angular, tech-laden 1980s sportscars as well as old appliances (and old stuff in general; I type on an IBM Model M, Print to a LaserJet III, and lament that I can't effectively compute on my IBM 5155. I still have and use Laserdisc and Betamax.) I could go on and on about beautiful machines of all sort and the struggle to make them function as intended.

 

[danemodsandy]

Funny...

...How we're all different in our approach to vintage. For me, collecting vintage is a chance to get rid of tech that's not needed. My centre-dial Maytags wash and dry well without the hinky electronics found on today's machines. My Volvo gets me around without a plethora of onboard computers that no one knows how to fix, or even exactly what they do, it seems.

I do appreciate older technologies. My Polaroid SX-70 is a very elegant design, both in appearance and its approach to doing its job. I loved Betamax- I did not see that picture quality on home video again (once VHS gained dominance) until DVD came out. And I had much more fun with my IBM 8088 computer with its 2400 baud modem than I've ever had with a computer since (can you spell BBS?).

But it's also fun to render yourself free of some overly complex technologies that generate as many problems as they purport to solve. Today's refrigerators certainly have a mind of their own, and that mind can save energy. So can keeping an old reefer properly defrosted, LOL.

 

[nasadowsk]

I wouldn't condem the motor just yet. I've got my money on the start capacitor. Pull the motor out, anyway, clean the shaft/bearings/wipe it off. And find the start capacitor, and go buy a new one - it has to be the same ratings. Once you hook it up, I bet the motor starts and runs beautifully. Cap troubles are generally what cause 'no start' conditions on these things.

 

[toggleswitch]

Thank you for posting a pic of this in another thread.
Surely a classic.

 

[red_october]

So...

Where do I look for the start cap???

 

[panthera]

Kransky Oktybar,

A fifty year old capacitor would be more likely to fail than a fifty year old motor.
The capacitor is dangerous, this has been mentioned already. It also contains PCPs and other nasties so be careful.
They come in various forms but since these units have to stand up to weather exposure, they usually look a bit like the picture below.
Don't forget to discharge the terminals properly.
By the way, in a unit that old the motor is bound to be a standard production fractional horsepower, GE made them by the billion. It will have a reference number which can be used to exchange it for a generic brand.
There will probably be at least one other if not two other capacitors in that housing, they will all be at the limit of their useful lives.

 

[red_october]

Thanks. Where in the unit will I find this capacitor? The motor is definitely a regular GE 1/10th HP with a refference number. Its statistics are printed on it too, 115V, 60 cycles, 1.14 Amps, I believe, and something like 1175 RPM. So finding a replacement shouldn't be difficult. All this is, of course, assuming that simply oiling the motor with WD-40 and then some propper oil doesn't clear this up. Where do I purchase weather-hardened capacitors? Will the appliance parts shop have them?

 

[panthera]

These

are standard units and have been for many decades. The cap(s) can be just about anywhere; since their location is not important to their functioning (and they outlast most other components) you often find them tucked away in the oddest corners. Capacitors are sold in standard values and you will have no trouble finding what you need at any repair house or through a catalog. The weather proof part doesn't mean they are made to run under water. Do not believe the clerk who tells you you have to adjust capacitance to reflect the higher voltage in use today, blah blah blah, etc, etc. Stick with what is marked on the schematic or the capacitor or stamped into the motor frame. Oh, usually the capacitor will be rated at double or quadruple voltage, that is not important - just not under-rated.
One sure way to find it (them, remember, if this one is shot the others are not far behind) is to trace back the wires from this motor. Of course, we still are not positive that it HAS a capacitor hooked up in series. There are other solutions available here so you may not be out of the woods yet. Oh, one thing which occurs to me: Could it be that this motor is not getting the voltage it needs? You said it is 115v. Does it have two or three wires running to it?
If only two, then try hooking it up to the line directly. If it purrs along, well then, it is something else. It there are three wires, then you probably do have a capacitor in series with the starting winding. Or, other possibility, this motor is not original and somebody made a mistake in hooking it up.
I have kept quiet on the lube front, but if you don't mind my .02cents...I think you should not be spraying WD40 in the housing of this airconditioner. It stinks forever and since this thing constantly moves air into and out of the room, you could well end up with long-term stink.
WD-40 is a good "un-freezer" and a lousy lubricant. In my opinion (ok, more than just my .02cents, sorry) it is best to do the job right: Carefully disassemble the motor, clean the shafts (no sandpaper), re-oil the bearings with a decent oil (20w is cool, if it is non-detergent and non-acid) then re-assemble being careful to tighten evenly and not too tight (hand tight not arm tight) with lock-tite or somesuch.
Such a pretty unit, I bet you will soon have it up and running.

 

[red_october]

Thanks

Since it is a slide-out I can do that. The motor has 5 wires, black, brown, white, blue and red. Two go to line, one is tied across hot with the capacitor (natch. I was hoping it didn't have one), and three go to the switch and are labeled as to speeds the motor is capable of. The unit has only one speed, though. I will try to re-condition the motor and we'll go from there. Hopefully I will have time to do it tomorrow after work.