TAC-110 fan capacitor

[EngiDent]

Hi folks
1967 Land Yacht Overlander with original TAC-110-1 air conditioner. Due to some shoddy work years ago, the (aftermarket) fan capacitor fell down in the bottom of the electrical box, which itself is rusted out at the bottom, so it got wet and the terminals rusted (nearly) off. Fan would run on low if I hand-started it, but would not run on high at all. The label is rubbed off of the capacitor, so I don't know what capacitance to match it to. What spec should I get?
Also, is there a polarity on the fan capacitor I should observe?
Last question... Is there such a thing as a replacement for the filter? Manufacturer / pn? Or do I have to do as listed in other posts, cut up a home filter and rig this old one?
Thanks!
Dave

[TomW]

It sounds like the capacitor is still good and you cannot connect to it. If that is the case, an HVAC counterman will have a multimeter with a capacitance setting behind the counter - he can measure the capacitance to sell you a direct replacement.

If the capacitor is bad, take many pictures of the fan motor, especially the spec plate, and stop by a motor shop. Those guys will probably recognize your motor and be able to sell you a capacitor that will work.

Tom

[TomW]

Oh, and there is no polarity on AC capacitors.

Tom

[EngiDent]

Thanks, good point. I *think* it's still good. It was working until I had it open to top off the R22 a couple months ago. I checked the capacitors, and tried cleaning up the rusty tabs, but one side was so bad I think I bent and partially broke it. That's when the fan problem started... Worked fine on the 30 amp in my driveway, but not so much after a 4 hour trip.

[EngiDent]

Here is the capacitor in question. It is aftermarket. I know it was replaced in 1990, maybe more recently too.

[TomW]

Your capacitor is most likely rated at 5 mfd, 370 vac like my Overlander's two replacement fans' capacitors have been.

Of note, your first image shows the LH capacitor lug clearly overheated. I have seen this before and it is not because your unit is drawing too much current it is because the double-prong connector is not rated for the current passed between the two wires (the capacitor does not continuously pull current and only serves as a mounting post). As a consequence, the connector heats up and smokes the capacitor & wiring. My solution has been to solder the two wires plus a short pigtail together, and attach the pigtail to the capacitor.

Hope this helps,
Tom

[EngiDent]

Thanks again. I was thinking I would dip the wire tips in muriatic acid to clean the 53 year old gunk off of them, and then solder the connectors on. So I'll solder the 2 wires together and then solder into the female connector.

[TomW]

Originally Posted by EngiDent

Thanks again. I was thinking I would dip the wire tips in muriatic acid to clean the 53 year old gunk off of them, and then solder the connectors on. So I'll solder the 2 wires together and then solder into the female connector.

No. It would be better to cut back to clean wire and solder a pigtail to the old wires. Then crimp/solder the pigtail to a female spade connector. Soldering the TWO wires to the connector will add too much mass - vibration going down the road will not treat the union well.

Tom

[EngiDent]

I see what you mean. I'll try that, solder together then single wire to cap. What I meant by acid was that every time I've had to strip any wire in this rig, it has had dark colored sticky goo all over it under the insulation. No matter how far up I cut.

[TomW]

Originally Posted by EngiDent

... What I meant by acid was that every time I've had to strip any wire in this rig, it has had dark colored sticky goo all over it under the insulation. No matter how far up I cut.

Muriatic acid will wick into the wire and corrode it where it cannot be washed off. My experience has been that rosin core solder used on copper wire with a soldering GUN is sufficient to clean the goo (resins from the insulation) sufficiently for a good bond. The newer zinc? coated wires need to be treated differently. I have high confidence your Airstream has copper wires.

Tom

[EngiDent]

I hadn't thought of that. Maybe acetone or MEK? Definitely copper. I'll try the gun first and see if I can get it to stick, but I haven't had much luck with it in the past.