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The idea of an alternator under the car on a postwar model seems to be problematic because of the frame X being right where the power takeoff would need to be. That doesn't leave enough room for even a mini alternator to mount without doing some surgery and that is something I would rather not do.

As to AC components, there are apparently no longer any 6v clutches to be found and dual shaft 6v blower motors also seem to be extinct.

Sanden specs say the stock clutch will pull in at approx 7.3v and I know some are being used on 6v cars. It must work using the generator output voltage to pull in. If the generator is not putting out it's normal volt or so above regular battery voltage the clutch is inoperative. Dwight Heinmuller has the Sanden too and mentioned checking with a Sanden rep who said the compressor would work that way but it was his unofficial opinion as obviously he couldn't endorse the use. Dwight has factory AC in his 54 and had to replace a failed compressor. I don't know what others with Sandens on 6v are using for their AC units but aside from yours I know there are several others out there.

On the blower side, there are 6v single shaft heater motors readily available and I've played around with converting an Old Air single blower Hurricane unit to use one. It is adequate but not as fast or as powerful as the 12v motor -- I'd estimate it is about 10-15% slower. Its regular 12v 3 discreet speed motor will work on 6v but at that voltage, compared to the regular voltage, the high speed is more like medium and medium is more like low. The third or low speed is almost useless at 6v.

Is your Custom Auto unit the typical underdash hang on dual blower setup with the double shaft motor and does it appear to be running at a normal speed? If so, I am wondering if when the installation was done 6v motors were still available or perhaps the blower motor was rewound to work on 6v.

Hi Howard

I'll get back with you on whether the blower is running at 'normal' speed. With a sample size of one that will be quite subjective.

I don't know any of the details of my AC installation. Clearly southern California is filled with folks that could rewind an existing blower motor to 6 volts. I'm led to believe the polarity change will result in a motor that rotates in the opposite direction. The fan will lose some flow at constant speed that could be recovered with a slight bump in motor speed . . . assuming you can tolerate the current increase. All of that activity could have been done 'in-house' at CAS.

Every so often the subject of the compressor clutch will come-up at the Saturday evening car show. We are equally at a loss as to whether this is truly a 6 volt item or a 12 volt unit operating at essentially below the recommended minimum voltage. If I can find some coil resistance data I can measure mine and put this to rest. Clearly the AC would be activated after the engine is running and if the voltage regulator was less than full normal operating temperature the voltage would be biased high. My car, once started, will have a system voltage of 7.5-7.6 volts until the regulator warms . . . then it's in the 7.1-7.2 volt range.

There is also the issue of 'pull-in' versus 'hold' voltage. A half volt between the two would make a world of difference.

My unit is mounted hanging off the lip at the bottom of the dash. The 'far end' of the evaporator is essentially resting on the transmission hump. I have not disassembled to view the configuration of the motor, but I would expect a double shaft design . . . AC designs like to have lots of exit velocity and noise as surrogates for performance.

I've got a pretty good sized rheostat, perhaps I could map the clutch performance envelope of pull-in and release voltage levels. It's hard to measure the release voltage with only the unit's ON/OFF switch.

I have been toying with the idea of having an 'on-board' converter on my '54 with some type of current limiter so I can re-charge the 'constant loss' 12 volt system if the voltage gets on the low side. The two six volt Optima batteries combine to a lot of hours of running the radio. Right now I trickle charge once every three weeks.

Have you made a decision on whether your system will have a common ground?

dp

Quote:

Not entirely.. AC and the 47 has kind of been on the back burner lately and right now it is 12v positive ground. There is nothing really polarity sensitive in my unit. I bought and modified a very low key basic AC to fit my prewar replica evaporator case. If the compressor clutch had a built in back emf diode which would be needed with an electronically controlled unit that would be an issue (as would an entire electronic AC) but the one I have does not have a diode.. If I make the switch to an alternator then it becomes a question of whether a 12v positive ground alternator is readily available. Haven't really researched what is available in depth yet but if it requires something custom then will probably do the neg ground for AC.

Common grounds are not an issue as long as the two power supplies and the items they feed are kept separate and there are no feedback paths. The big issue for us comes about when you have something with switched polarity that can accidentally touch ground. Something like a phone charger plugged into a separately powered 12v negative ground outlet with an exposed tip that could fall across and touch a positively grounded item. Typically the metal shell of the usb plug or charger tip end is at the same ground potential as the power outlet. That would result in a series connection between the two power supplies so in our Packards, an 18v direct short.

Howard

I called CAS today. They disavowed any knowledge about the AC system in my (Bill Lauer's) '54. Their comment was they do not install or work on AC systems, so although I'm never wrong this time I was a little short of being right. I found the stack of receipts that came with the car when I bought it, and there was a single page, not quite a receipt, but a single page with no letterhead, that detailed some of the parts and cost associated with the AC installation. On that page was mention of an automotive refrigeration business in Orange, CA. I'll call them tomorrow and post the details of that conversation. Perhaps that company configured units to the desired voltage and polarity . . . one can only hope.

I have some amount of experience with PMs, they been used on motorcycles for years. I see only two wires in the photos you posted. My bet is that is the AC output of the alternator, with all of the rectification and voltage limiting provided by the 'regulator'. That's the good news is, you can configure whatever you want. The PMs in a Harley produce at least about 12 volts per 1000 rpm . . . that's the AC voltage. So at full song the AC voltage is north of 70 volts. The regulator is heavily finned and faces the wind. I suspect if I cut one apart I would see a rather large Zener along with a diode based bridge.

dp

I'm waiting the arrival of a small denso 12 volt alternator (ebay) to replace the same kind in my 54 Cavalier.

I need to run the fan and the compressor clutch.

Add on R-12 system. (I have 12).

I will add a small 12 volt battery to replace the dead one.

The original car system is pos ground 6 volt and my add on is 12 volt neg ground.

Works OK.

Converting the car to 12 is not an option for me.

Jim

With the extra wide belt on the 356 engine and no wide pulleys easily available plus not having belt space for anything else, have been giving plan B some thought. Acquire a PS version of the early 50s Mopar generator and see what is involved in using the power steering coupling on those to run one of the small pancake style 20 amp 12v PM alternators off the back of the generator.

Howard, clever idea. All you would need, I think, is the MoPar's armature and commutator end housing to go on your Packard's Auto Lite generator. JWL

I happen to have one of the mopar gens and the power steering pump if anyone is interested.

Just an update to the PM alternator idea. Here are a couple of in progress photos. The generator has not had the new brushes installed yet.

Acquired the 6v Chrysler generator from Dell and mounted a small 12v 20 amp alternator on the back in place of the PS pump. Generator was kept absolutely stock so the PS pump can go back if desired.

Whether I ever get around to putting the thing on the car is another question but at least it is now an option. If it happens, am thinking a maintenance free 12v battery under the car will work the AC and any modern 12v accessories that might be wanted. 20 amps should be more than enough to keep that battery charged. It does require an external regulator but that is a small flat package that can go next to the battery.

The Chrysler generator has a 3/4 shaft while the Packard is 5/8. Made the wide belt pulley from scratch rather than destroy a Packard pulley. The fan is a stock aftermarket alternator part. That pulley is aluminum for now. If it goes on the car I may need to find a machinist to make one out of steel.

The original plan was to mount a stock alternator to the generator so it could be easily replaced in case it failed and made a bracket to that end The more I looked at that version the more undignified and out of place the arrangement seemed like it would look in the car. Bit the bullet and revised the mount and modified the alternator to fit. I would have made the mount flush to the generator end to cover the gap but decided the generator ventilation would be compromised. There is provision for the alternator to draw air but there are no vent holes in front so no idea how much it needs. All it has is a dozen or so coils of wire on an iron form with magnets spinning above them. Rather than cut the threaded mounting ear off the alternator decided to keep it in case a secondary support bracket is needed.

Overall, I believe the second version looks much better and being mounted low in the car is less likely to be that noticeable. The second mount also reduced the overall length to 14 inches which nicely fits the space available.

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I bought a 1 wire Denso alternator (35 amp) on Ebay, it has a built in regulator for less than 70 bucks, new.
The Kubota type is very similar to the way the under flywheel type alternators work on tractors, uses a simple regulator similar to them. One thing with these is you need a switch to disconnect the battery from the regulator when the engine is not running it or it will ruin the voltage regulator in time.
John