3000W Chinese Gensets Info.

professor95 wrote:

rogerw2 wrote:
Professor, and All,

I have purchased a Champion C46540 for RV use to power a Dometic 13.5BTU-hr A/C. I had previously borrowed a friends 7.5KW Generac and Man, was that noisy! Being a semi-retired EE, I did my calculations and came to the conclusion that 2KW ...... snip
rogerw

Wow, you ask some really complex questions. Actually, the questions bring to light some problems I really had not noticed.

I need to do some of my own research into this before I respond. Meanwhile, perhaps Bob (TopRudder) and George (Mr Wizard) will also jump in. I do not mean to insinuate the two above are the only guys on this thread who can contribute - obviously there are many others who have similar expertise.

One comment though, just about all of the newer 13.5 and 15K air conditioners using the scroll compressor also have what is commonly refered to as "soft start" technology. This is extremely effective and even allowed me to lock in the compressor on my previous Coleman 15K A/C with voltages as low as 85 VAC with a 1,700 watt mechanical inverter (dynamotor). If your A/C is of a similar design you really do not need to go further.

BTW - welcome to the forum. If you are reading all of the pages, you are definately my new hero!

Thanks for quick reply! And I really do wish to compliment you and others on this forum....very informative and collegial!

I hope I did not imply to anyone that I had any trouble using my C46540 to run my 13.5K A/C..... It runs it very well; as others have said, "like a Champ!"

I did have a little rocky road getting to that point because of
a) my basic unfamiliarity with HVAC, which I have been lately trying to remediate, and,
b) the mud dauber nests that were built onto the fan blade and rotor cage blower during inactivity and before purchasing the genny! (whump! whump! whump!)

The "unfamiliarity" led to an early finding that mysteriously I could cut the air successfully on at the genny switch each time, but not at the thermostat.....turns out I was cutting the air OFF and THEN back ON at the thermostat, not giving the PTCR time to cool for a recycle, hence I would get the full locked rotor current and bog the genny down without re-starting. (When I would go out of the TT and do this at the genny, I was giving the PTCR more time to cool.) Once I studied up a bit and realized that I was causing the issue, no problems at all that I can detect.

Of course, cleaning out the mud-dauber's nests gave me oppty to familiarize myself with my A/C unit (bonding...!) and to insulate various cold tubes with foam insulation and the external surfaces of the cold plenum with insulating sheathing such that it is more efficient now.

But it did get me to thinking that maybe I could improve the "soft start" characteristics with a EPR instead of a PTCR operated start capacitor. Also, I like the timeout feature of the E-Series Supco products since, if a PTVR were to fail "closed" it would tend to burn out the start windings in the compressor motor. I suppose the Supco could also "fail closed" too, but it is presumably much more reliable than the common thermo-mechanical switch.

My unit is only 3yrs old, and my guess is that you are correct that I do not really have to do anything to it for pure startup reasons. (I don't have a Clamp-style Ammeter to prove what the peak startup is....so I am guessing this is so.) However, my curiosity has been aroused as to what voltage a SPP6E and a SPP4E actuates the relay cut-out...and whether folks may be inadvertently really depending on the time-out instead of the potential feature of the product, and the reply from Supco left me still skeptical.

BTW, I am trying to convince myself why I should not go out and buy a second C46540 as a backup, just in case.....

Kudos and thanks!


YHS,
rogerw