Skip to main content ↑ ↓
Topic: Genset AC power frequency (Read 1027 times) previous topic - next topic

Genset AC power frequency

I started and ran our genset this morning and used it to power our coach (lighting, heat tape in air conditioner, then the air conditioner and the fan over the cook top) for a while.  After running the genset for a short while, I checked the display on the Progressive Industries 50 EMS unit I installed earlier this week. 

The display was reading 58 HZ instead of 60 HZ and had a code of PE08  (line frequency low).  Is this an acceptable frequency or is there a way to adjust it to the 60 HZ?  If it can be adjusted, how do I make this adjustment?  (If I didn't have the Progressive Industries  50 EMS installed, I would not have known about the 58 HZ frequency.)

Thank you very much.

Morris
Morris and Janice
1997 U270 36'

Re: Genset AC power frequency

Reply #1 –
When I was trying to figure out my genset problems, the chief engineer from the company I work for checked the frequency and found it at 60 cycles or very close.  It fluctuated a little (58-62) and he didn't get excited by it, saying it was normal.  I seem to remember that it like to stay at 59 mostly.  My problem turned out to be a failing ignition coil.
Dwayne Keith
1992 U240
3116/MD3060

Re: Genset AC power frequency

Reply #2 –
Quote from: Dwayne –
When I was trying to figure out my genset problems, the chief engineer from the company I work for checked the frequency and found it at 60 cycles or very close.  It fluctuated a little (58-62) and he didn't get excited by it, saying it was normal.  I seem to remember that it like to stay at 59 mostly.  My problem turned out to be a failing ignition coil. 

Sounds like our genset frequency is OK then..... that is good news!!!  Thank you very much.
Morris and Janice
1997 U270 36'

Re: Genset AC power frequency

Reply #3 –
For the useless info fans, the UL acceptable limits are +/- 5% on freq, and +/- 10% Voltage
 :)

Re: Genset AC power frequency

Reply #4 –
Genset frequency is changed by adjusting the throttle governor lever which is often identified by its lead seals. Frequency is determined by generator RPM and the governor's job is to keep the correct speed under varying loads. If the frequency is always near 58 under different loads, the RPM should be adjusted up a little at a time. As you can see EMS considers 58 out of correct range. Important for many USA electrical devices that frequency be very close to 60 cycles per second

Re: Genset AC power frequency

Reply #5 –
Especially clocks...
The selected media item is not currently available. Dave Head & Megan Westbrook
Titusville, FL - The Great Outdoors
'98 270 buying this month
Toad is a 2018 F150 XLT

Re: Genset AC power frequency

Reply #6 –
Quote from: Dave Head –
Especially clocks...

I spent most of 1970 on a combat base near the DMZ in Vietnam. All power was from a local generator. I worked in the MARS station (radio geeks). The generator operators would call us to help set the speed on the generator.  If our wall clock was running fast, the generator was running too fast. If our wall clock was running slow, the generator was running too slowly. If 60 seconds on the wall clock matched 60 seconds on an accurate wrist watch, the generator was right on.

Most clocks now use an internal frequency reference. "Old timey" electric clocks ran synchronously with the power line. You can set the speed of your generator with an "old timey" electric clock or with a frequency meter. The "Kill-A-Watt" meter will show voltage and frequency at any outlet in your coach. Chances are that the frequency will drop a bit with heavier loads. If the frequency is in the range of 58-62 Hz (cycles per second), you are doing fine.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX

Re: Genset AC power frequency

Reply #7 –
The generators in our Foretravel motor homes use a mechanical governor on the engine.  The governor does a very good job or controlling the rpm/frequency of the generator.  the UL standard for generators as I mentioned earlier is simply 5% on frequency and 10% on voltage.
5% on freq is 57 to 63 cycles/hertz.  If your equipment has the UL label, it will operate fine within these standards.
Now IF you want better governor control, you can opt for an electronic isochronous governor.  It will maintain the desired frequency 60 Hz. with in the horsepower limits of the engine.
The down side of the isochronous governor, it is not CHEAP and not as reliable as the mechanical governor in the present Kubota diesel engine.  The isochronous governor is subject to various ailments depending on the make, style and cost.
For better control, you best purchase a very long extension cable and keep connected to your home circuit as you travel.
There are solutions like the new Onan 12-18 KW as used in the new high end Foretravels.  It is a variable speed engine, so is not dependant on the governor for freq. control.

Re: Genset AC power frequency

Reply #8 –
J.D.

I was a 52B20 Generator Operator and Mechanic in a hospital reserve unit from 1966 to 1972.  I was trained on generators up to 60KW (Ft Belvoir, Va) and I seem to remember that the gensets all had a vibrating reed frequency meter on them which I thought was supposed to be accurate.
John Cooper
'91 GV 36'
Oshkosh chassis
Cat 3208T 300HP
 

Re: Genset AC power frequency

Reply #9 –
Quote from: John Cooper –
... I seem to remember that the gensets all had a vibrating reed frequency meter on them which I thought was supposed to be accurate.

I expect your recollection is accurate. I don't know what kind of instruments were on the generator at the combat base, nor do I know how competent were the operators. In the MARS station somewhere near the DMZ, we had a pretty good analog voltmeter on the wall, and an analog clock that used a synchronous motor. The guys operating the generator would call us to check on the frequency and voltage they were delivering to our station.

Fortunately, the Collins radio gear we used to run phone patches into the US was pretty tolerant of adverse conditions.

Based on my experience, I would expect the Powertech generators would generally provide output of appropriate frequency and voltage for a coach unless there is a significant problem. A significant problem would probably expose itself in the sound of the engine, or a severe deviation from the normal voltage shown on the power monitor.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX