speed of drive for AC compressor

[larryh]

I've checed my manual to find the speed of the drive for the AC compressor on my 1974 8V71 Buffalo 4905 I'm looking at a AC generator to provide electric when driving.

The generator is rated at 545 RPM

LarryH

Quartzsite

Been in mid 80's last week or so can take a lot of these days and lot's of room here in Desert so when u tired of shoveling that white s*$# come on down LOL.

[TomC]

That generator sounds like it was for a PTO drive off a tractor.  If so, those generators have a gear drive to up the rpm to either 1800 or 3600rpm that the generator is actually rated for.  If it is small in diameter-like less than a foot, then it is most likely an 3600rpm.  If it is bigger in diameter, an 1800rpm.  I would suggest you remove the gear drive and use a normal 2 or 3 belt pulley to the engine.  The main problem with an AC generator to the main engine, is that AC generators should have very closely controlled rpm, since rpm is what controls the hertz, or cycles per second-in our case 60 cycles per second (that's why either 1800 or 3600rpm-or either 2 pole or 4 pole alternator).   It would probably be easier just to buy either a small Diesel or gasoline engine to power the AC alternator, then you'll have control over the rpms.  The easy rule of thumb is, whatever the output of the generator, just double it for the horsepower of the engine to power it.  For example- a 6,000 watt or 6kw gen would need a 12hp engine.  Good Luck, TomC

[boogiethecat]

Look at this ebay item
330284054671   

It's a brand new Auragen kit, complete.  It's configured in a similar technology to honda inverter-generators and doesn't care what speed the engine is running as long as it's "fast enough" (over 1000 rpm or so when the belts are properly ratio'd to it) and it'll give you a pure sine wave 60hz AC at 5KW while you're driving.
This kit is a really good deal- it's new and complete, and they cost 4-5 times this much from a dealer.  A buddy got one and he's real happy with it (the seller has/had more than one)

Cheers

[RJ]

I've checked my manual to find the speed of the drive for the AC compressor on my 1974 8V71 Buffalo 4905.  I'm looking at a AC generator to provide electric when driving.

Larry -

The PTO for the A/C compressor on your coach (off the front of the engine near the torus drive for the fan), runs at crankshaft speed.  For folk who have a PTO on the side of their V-730, it, too, runs at crankshaft speed.

FWIW & HTH. . .

[larryh]

Thanks RJ thats what I was looking for the inverter/generator is a a bit pricy and I will have to machine a adaptor to mount it so will be looking at ebay a whole lot. Tom C. I do not want any belt drives on my unit at all and there is no need to buy another engine to run I do have a Onan 5.5 Marquite quiet gen when the big engine is not running.

LarryH

Quartzsite AZ

[Tony LEE]

What do you intend powering from the engine driven generator.
As Tom said, it is just not possible to run any motor or anything with a transformer in it from a source that varies so much in frequency - say from 25Hz to 65Hz - and another bigger problem is that with most simple generators, the output voltage also varies widely with speed.