Reply
 
Thread Tools Display Modes
Old 06-26-2013, 09:32 AM   #1
Senior Member
 
Mike & Molly's Avatar
 
Join Date: Apr 2013
Location: New York
Posts: 120
Question Generator Question

Yesterday I was "exercising" the Onan generator on my 3010DS.
Once started , I turned on the AC unit, & the refrigerator to put a good draw on the generator, which I let run appox. 1 hour.
At the end of the hour, I shut down the AC & the Refrigerator, & had nothing else running in the RV, but left the generator running.
I noticed the RPMs did not go down to a lower idle, once there was little if any load on the system.
Is this normal (running at full RPM all the time)?
Or should the RPM adjust according to the draw/load?
It's still under warranty.
Any help/info is appreciated.
__________________

__________________
Mike & Molly is offline   Reply With Quote
Old 06-26-2013, 10:07 AM   #2
Senior Member
 
Join Date: May 2013
Posts: 254
Mike,
I believe there should be a noticeable difference in the generator RPM's when the A/C unit is running and cooling. Maybe shut everything down again and just use the A/C as the load and see what happens. Have someone stand outside by the generator when you turn on the A/C to listen. The generator should vary its RPMs based on the load otherwise it is burning more fuel then necessary.
__________________

__________________
Tim

2013 Forester #3051SF
2009 Toyoda Tacoma (toad)
2010 Newmar Dutchstar (Sold)
2011 Fleetwood Bounder (Sold)
trwmodela is offline   Reply With Quote
Old 06-26-2013, 10:28 AM   #3
Senior Member
 
wyo700's Avatar
 
Join Date: Jul 2012
Posts: 892
The only time you will notice a change in rpm is when it's loaded and then the Rpms will drop just slightly. Other wise the Rpms you hear at idle are kinda high but normal.
__________________
2012 Sandstorm 203slc
2013 Toyota Tundra
Eqil-l-izer hitch,Prodigy P3
2014 Honda Pioneer 700-4
2004 Yamaha Grizzly 660
wyo700 is offline   Reply With Quote
Old 06-26-2013, 11:01 AM   #4
Senior Member
 
Join Date: Oct 2012
Location: Cobbs Creek, VA
Posts: 201
Its generating a/c so freq = f(rpm). A change in sound when unloaded, but not speed
__________________
Geri is offline   Reply With Quote
Old 06-26-2013, 11:19 AM   #5
Plain Old Member
 
Join Date: Nov 2012
Location: Full Timing in South Louisiana
Posts: 1,938
Like they said. Constant 3600 rpm to maintain frequency / voltage etc. just change in sound by load demand. I prefer these over the ones that idle down when no load. My Hondas do that, and it gets aggravating hearing them change. Oy thing when exercising onan, let it run a little bit once loads are removed before killing it.
__________________
John and Rebecca Dickson
Emma-7 / Little John-5 / Iva-1
Full Timing Again, Rev B
2013 Ford F-350 Lariat CC LB PSD
2015 SOB TT - With OC's Awning Poles (#8)
At least in Heaven, RVs will be perfect, and I won't have to keep fixing them.
BigJohnD is offline   Reply With Quote
Old 06-26-2013, 01:37 PM   #6
Senior Member
 
Join Date: May 2013
Posts: 254
My Class "A" diesel generator was 8KW and it had a more noticeable change in sound with a load. But it was running two A/C units, a residential refrigerator and other goodies. I also have a large portable Honda generator for the house here in South, Florida. There is a throttle switch that allows it to run auto or full rpm's.
__________________
Tim

2013 Forester #3051SF
2009 Toyoda Tacoma (toad)
2010 Newmar Dutchstar (Sold)
2011 Fleetwood Bounder (Sold)
trwmodela is offline   Reply With Quote
Old 06-26-2013, 08:59 PM   #7
Member
 
Join Date: Nov 2011
Posts: 85
Most generators of the size and type ours are operate at 3600 rpm with or without load.
__________________
budblack is offline   Reply With Quote
Old 06-27-2013, 08:16 AM   #8
Senior Member
 
MotocrossCamper's Avatar
 
Join Date: Nov 2010
Posts: 653
Just to add to what most have said, the Onan will not change rpm, just sounds like its working harder under a load.
__________________
MotocrossCamper is offline   Reply With Quote
Old 06-27-2013, 08:25 AM   #9
Senior Member
 
Join Date: May 2013
Posts: 254
My Class "A" diesel Onan was 8kw. The fuel burn chart for it showed a use of about 1/2 gallon at 1/2 load and just over 1 gallon at full load. Not sure how is uses less fuel if the RPM's remain constant. What do our generator experts believe?
__________________
Tim

2013 Forester #3051SF
2009 Toyoda Tacoma (toad)
2010 Newmar Dutchstar (Sold)
2011 Fleetwood Bounder (Sold)
trwmodela is offline   Reply With Quote
Old 06-27-2013, 08:48 AM   #10
Site Team - Lou
 
Herk7769's Avatar
 
Join Date: Oct 2009
Location: South Eastern PA
Posts: 21,158
Well, this is a motorhome thread and I don't have one.

The way I understand AC power generators (NOT A EXPERT!), there are two ways of governing (controlling the speed) in order for the output to remain at 60 cycles per second and it depends on the type of inverter you have.

A solid state inverter can take varying cyclic input (rpm of the alternator) and still output 60 hertz. These generators are easily identified by the "ECON" setting which allows the ROM to ramp up and down depending on load. They are very fuel efficient in ECON, but are slow to react to rapid demands on current (like an Air Conditioner starting up). If you are going to run an AC off these generators, the manual recommends "NORMAL."

A "contractor" type conventional generator that uses a rotating (mechanical) inverter and they MUST run at a constant 3600 RPMs regardless of load in order to produce 60 cycle AC. As load increases, the RPMs start to slow down, (like a lawn mower getting into tall grass) and the mechanical governor increases fuel to keep the RPMs constant.

This must be the type of generator you have.

Source:
Conventional vs. Inverter Portable Generators - Cabin Life Magazine
__________________

__________________

Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW
Herk7769 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



» Virginia Campgrounds

Reviews provided by




ForestRiverForums.com is not in any way associated with Forest River, Inc. or its associated RV manufacturing divisions.


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 01:52 PM.