Re: Aftermarket Air Conditioning

Posted by HH56 On 2023/7/9 21:31:31

I think he was referring to the dual shaft 12v blower motor as not having a 6v replacement and was probably the reason he automatically went for the converter. You are correct in that he is undoubtedly raising voltage then lowering again and could surely power the motor directly at some lower fixed speed. I started to do the 6v lower voltage with my repro prewar AC in the 47 which is based on a 12v modern unit. Was not happy with the airflow since the max speed was only about medium low. With the unit in the trunk I could not feel much air in the front. Stuck with 12v but then went with an automatic switching dual battery setup. Am rethinking that approach now if I ever decide to finish the project.

You can get 6v universal single shaft heater motors but not 6v dual shaft AC motors. The heater motor is smaller and not quite as powerful so only maxes out at about med high as a comparative speed. To run dual blowers with that motor would take some re-engineering and some kind of long shaft setup. It still might not be powerful enough in the end.

I also wondered about the single switch for everything and can only conclude he probably started wth one of the inexpensive aftermarket units with blower controls that use a rotary switch to do the on/off and select a fixed specific size resistor mounted in a module for 3 disceet blower speeds. He obviously eliminated that switch and decided to only power a single resistor at whatever speed. If he has a 10 amp converter then medium or low would be my guess because many of those AC motors exceed 10 amps when on high.

The long unsupported belt lengths if on the slack side can start to whip at higher engine speeds so that is the downside to the long single belts. If it wears and loosens and then whips too much it can pop off a pulley and do some damage. That would also stop the radiator fan and generator. Even though it was only the compressor, Packard had idlers on both sides in their long factory dual belt arrangement on the 53-4 units. I think an idler would be advantageous to any install that has a similar length but without one just keep an eye on belt wear and tension.