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Why is the generator cycling??

supercub
Explorer
Explorer
Running the generator this morning. I have the frig on gas. Running a small 110 house fan. HWH is on gas. TV is on as well as the direct TV box. Other then that nothing else is on except the hidden devices. What is cycling causing my generator to fluctuate in speed and my amps to vary from 2 up to 16amps? Batteries were low (12V) when I turned the generator on this morning. I don't understand what is turning on and off to change the load on the generator.
13 REPLIES 13

atsrmf
Explorer
Explorer
A generator will vary in speed based on electrical load. The alternator is trying to maintain the correct 60hz frequency needed for American standards. When an A/C is turned on, a mechanical resistance to the engine is created due to the magnetic resistance created in the rotor. The engine governor adds throttle to compensate for the drop in RPM.
3600 Rpm = 60 cycles per second. If the frequency drops the current (amperage) builds up along with heat. When the alternator reaches 3600 RPM voltage and frequency will be correct.

wildmanbaker
Explorer
Explorer
wa8yxm wrote:
How frequent is the cycling. Nobody has ask that.
Running up and down every second is the air/fuel mix (Carb setting) on a gasoline generator

Running at low amprage for oh say 20 hours then Kicking up.. Progressive Dynamics Charge Wizard

Running low for oh say an hour then kicking up usually about 3 amps. Fridge auto switched to AC

There are more options too. (not sure of the fridge cycle time)
Its a Diesel Generator, not gas.
Wildmanbaker

wa8yxm
Explorer III
Explorer III
How frequent is the cycling. Nobody has ask that.
Running up and down every second is the air/fuel mix (Carb setting) on a gasoline generator

Running at low amprage for oh say 20 hours then Kicking up.. Progressive Dynamics Charge Wizard

Running low for oh say an hour then kicking up usually about 3 amps. Fridge auto switched to AC

There are more options too. (not sure of the fridge cycle time)
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times

sch911
Explorer
Explorer
Check the status of the Inverter/Charger while it's happening. It's probably charging your house batteries.
OEM Auto Engineer- Embedded Software Team
09 Holiday Rambler Endeavor 41SKQ Cummins ISL
2012 Jeep Grand Cherokee Limited Toad

2oldman
Explorer II
Explorer II
converter
"If I'm wearing long pants, I'm too far north" - 2oldman

jdc1
Explorer II
Explorer II
supercub wrote:
I have an Onan 7500 diesel generator. With a Xantrax 2000 watt inverter/charger. It cycles every couple of minute. I've let it run for a couple hours, batteries are charged, so I'm assuming it's the charger that is cycling. I wasn't aware while charging the charger would cycle, why is that?


Because you are using 12v's somewhere (lights, CO detector, radio memory). You're water heater will turn on and off too, as needed, causing the genset to rev every so often. If it bothers you, put a constant load on it like so many have said.

supercub
Explorer
Explorer
I have an Onan 7500 diesel generator. With a Xantrax 2000 watt inverter/charger. It cycles every couple of minute. I've let it run for a couple hours, batteries are charged, so I'm assuming it's the charger that is cycling. I wasn't aware while charging the charger would cycle, why is that?

RLS7201
Explorer
Explorer
What your are experiencing is call "lean roll".
If you have a fuel mixture screw on the bottom of the float bowl, give it a 1/4 turn out and see what happens.

Richard
95 Bounder 32H F53 460
2013 CRV Toad
2 Segways in Toad
First brake job
1941 Hudson

Sagebrush
Explorer
Explorer
If its a basic gasoline RV generator its probably the carb/fuel/air filter or the governor. If it runs smoothly with a load check the governor setting, verify its putting out 120 plus volts at 60 hertz with a digital volt meter with the hertz capability. You can get cheap meters off Amazon for less than $50 and check it yourself. Generators don't like light loads, so if it runs fine with the A/C you probably just need to set the governor rod to 62 hertz. That usually gives you 126 to 130 volts with no load. With a light load it will always stumble occasionally, especially the smaller generators. The single cylinder 4KW models are glorified lawn mower engines, the V-twin 5500 types run smoother though, but they don't run any better than my John Deere riding mower either.

valhalla360
Nomad III
Nomad III
What type of generator? Gas/Diesel, inverter, built in/portable, etc... (exact model would be best)
What are you defining as "cycling"? Every 2-3 seconds or every few minutes?

If it's a carbureted gas inverter generator, could be a gunked up carb. This would be a continuous cycling every few seconds.

Or if it's reving up every few minutes, it's likely an intermittent load. Battery charger, water heater would be common items that you wouldn't hear kick on but would add a load causing the generator to apply more power.
Tammy & Mike
Ford F250 V10
2021 Gray Wolf
Gemini Catamaran 34'
Full Time spliting time between boat and RV

MountainAir05
Explorer II
Explorer II
X2 on puting a load on it.

jorbill2or
Explorer II
Explorer II
If the batteries were low ....Battery Charger?
Bill

way2roll
Navigator
Navigator
In the 2 MH's that we had the gen sets would idle up and down with no load. Based on what you outlined, your genny really has no load on it. Try running the AC.

Jeff - 2023 FR Sunseeker 2400B MBS