Low voltage out of Genset

[Alan]

My 87FC35 has a 8.0 kW genset. I am getting low voltage out of it
(around 95 volts). On my last onan genset (77 GMC - carbed gas),
this was a common problem and was simply corrected by increasing
RPMs. (If this is the fix, how do I adjust idle speed? This fuel
injection isn't as intuitive for me as I've been a carburetor guy.)

I found an installation manual for the genset and it says to adjust
some "taps" on a transformer regulator. It also says "output
frequency is determined by engine speed and normally does not
require adjustment." I'm not exactly sure what it means by "output
frequency". Is that voltage??

Is this problem more complicated than adjusting the RPMs? Maybe I
don't have one of the Onan manuals..?? I have a parts manual and an
installation manual.

I have searched the forums and did not find a post that seemed to
address my situation. Let me know if I missed it.

Thanks in advance,
Alan Johnson
87FC35

[Curt Sprenger]

I'm not an expert but found this on the Internet. For an oscillating or
varying current, frequency is the number of complete cycles per second
in alternating current direction. The standard unit of frequency is the
hertz, abbreviated Hz. If a current completes one cycle per second, then
the frequency is 1 Hz; 60 cycles per second equals 60 Hz (the standard
alternating-current utility frequency in the United States).

I recall the Onan guy adjusting rpms on our previous gen. set to get the
frequency to 60 and to increase voltage.

Sounds to me you are on the right track. If you can, turn up the rpms
and watch for voltage increase. Good luck. Please keep us posted.

Curt Sprenger 1987 PT38, Anaheim Hills, Calif.



Alan wrote:

> My 87FC35 has a 8.0 kW genset. I am getting low voltage out of it
> (around 95 volts). On my last onan genset (77 GMC - carbed gas),
> this was a common problem and was simply corrected by increasing
> RPMs. (If this is the fix, how do I adjust idle speed? This fuel
> injection isn't as intuitive for me as I've been a carburetor guy.)
>
> I found an installation manual for the genset and it says to adjust
> some "taps" on a transformer regulator. It also says "output
> frequency is determined by engine speed and normally does not
> require adjustment." I'm not exactly sure what it means by "output
> frequency". Is that voltage??
>
> Is this problem more complicated than adjusting the RPMs? Maybe I
> don't have one of the Onan manuals..?? I have a parts manual and an
> installation manual.
>
> I have searched the forums and did not find a post that seemed to
> address my situation. Let me know if I missed it.
>
> Thanks in advance,
> Alan Johnson
> 87FC35
>
>

[Pete Masterson]

I'd suggest using a Hertz meter as well. You don't want to move the
Hz too far from 60 as it can adversely affect motors, etc.

Pete Masterson
aeonix1@...
'95 Bluebird Wanderlodge WBDA 4203
El Sobrante, CA




On Aug 22, 2006, at 8:14 AM, Curt Sprenger wrote:

> I'm not an expert but found this on the Internet. For an
> oscillating or
> varying current, frequency is the number of complete cycles per second
> in alternating current direction. The standard unit of frequency is
> the
> hertz, abbreviated Hz. If a current completes one cycle per second,
> then
> the frequency is 1 Hz; 60 cycles per second equals 60 Hz (the standard
> alternating-current utility frequency in the United States).
>
> I recall the Onan guy adjusting rpms on our previous gen. set to
> get the
> frequency to 60 and to increase voltage.
>
> Sounds to me you are on the right track. If you can, turn up the rpms
> and watch for voltage increase. Good luck. Please keep us posted.
>
> Curt Sprenger 1987 PT38, Anaheim Hills, Calif.
>
>
>
> Alan wrote:
>
>> My 87FC35 has a 8.0 kW genset. I am getting low voltage out of it
>> (around 95 volts). On my last onan genset (77 GMC - carbed gas),
>> this was a common problem and was simply corrected by increasing
>> RPMs. (If this is the fix, how do I adjust idle speed? This fuel
>> injection isn't as intuitive for me as I've been a carburetor guy.)
>>
>> I found an installation manual for the genset and it says to adjust
>> some "taps" on a transformer regulator. It also says "output
>> frequency is determined by engine speed and normally does not
>> require adjustment." I'm not exactly sure what it means by "output
>> frequency". Is that voltage??
>>
>> Is this problem more complicated than adjusting the RPMs? Maybe I
>> don't have one of the Onan manuals..?? I have a parts manual and an
>> installation manual.
>>
>> I have searched the forums and did not find a post that seemed to
>> address my situation. Let me know if I missed it.
>>
>> Thanks in advance,
>> Alan Johnson
>> 87FC35
>>
>>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>



[Non-text portions of this message have been removed]

[Wilhelmus Schreurs]

Most of these generators either run at 1800 or 3600rpm, check which yours is
close to. If you are lower than either of these numbers, then you have to
adjust.

Bill
84FC35SB
Terrace, B.C.

Curt Sprenger wrote:
I'm not an expert but found this on the Internet. For an oscillating
or
varying current, frequency is the number of complete cycles per second
in alternating current direction. The standard unit of frequency is the
hertz, abbreviated Hz. If a current completes one cycle per second, then
the frequency is 1 Hz; 60 cycles per second equals 60 Hz (the standard
alternating-current utility frequency in the United States).

I recall the Onan guy adjusting rpms on our previous gen. set to get the
frequency to 60 and to increase voltage.

Sounds to me you are on the right track. If you can, turn up the rpms
and watch for voltage increase. Good luck. Please keep us posted.

Curt Sprenger 1987 PT38, Anaheim Hills, Calif.

Alan wrote:

> My 87FC35 has a 8.0 kW genset. I am getting low voltage out of it
> (around 95 volts). On my last onan genset (77 GMC - carbed gas),
> this was a common problem and was simply corrected by increasing
> RPMs. (If this is the fix, how do I adjust idle speed? This fuel
> injection isn't as intuitive for me as I've been a carburetor guy.)
>
> I found an installation manual for the genset and it says to adjust
> some "taps" on a transformer regulator. It also says "output
> frequency is determined by engine speed and normally does not
> require adjustment." I'm not exactly sure what it means by "output
> frequency". Is that voltage??
>
> Is this problem more complicated than adjusting the RPMs? Maybe I
> don't have one of the Onan manuals..?? I have a parts manual and an
> installation manual.
>
> I have searched the forums and did not find a post that seemed to
> address my situation. Let me know if I missed it.
>
> Thanks in advance,
> Alan Johnson
> 87FC35
>
>






---------------------------------
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[Non-text portions of this message have been removed]

[one_dusty_hoot]

Alan, the genset puts out 2 cycles per revolution,it
should run at 1800 rpm, govenor controlled. This would
output 1800 X 2=60 cycles per second. As load is
increased, the speed decreases, then more fuel is
given by the govenor to maintain speed.

Look at the governor next on the motor, there is an
arm that goes against a stop when the generator is
started. There at the stop point is the speed adjustment.

Before you start adjusting the stop you need to know
what speed your motor is turning. You can buy a
vibration tachometer at small motor repair shops.
You can move the wand in and out by turning the
knob. When the harmonic frequency is reached, the
extended arm will begin vibrating rapidly. Mayve $20?

Do not attempt to adjust speed without something as
a reference.

Your problem may be that the motor is running sour,
could be the air filter is clogged, and possibly not
enough diesel by a dirty filter?

Bob Janes 87FC35 Greenville, SC




--- In WanderlodgeForum@yahoogroups.com, Curt Sprenger
wrote:
>
> I'm not an expert but found this on the Internet. For an
oscillating or
> varying current, frequency is the number of complete cycles per
second
> in alternating current direction. The standard unit of frequency is
the
> hertz, abbreviated Hz. If a current completes one cycle per second,
then
> the frequency is 1 Hz; 60 cycles per second equals 60 Hz (the
standard
> alternating-current utility frequency in the United States).
>
> I recall the Onan guy adjusting rpms on our previous gen. set to
get the
> frequency to 60 and to increase voltage.
>
> Sounds to me you are on the right track. If you can, turn up the
rpms
> and watch for voltage increase. Good luck. Please keep us posted.
>
> Curt Sprenger 1987 PT38, Anaheim Hills, Calif.
>
>
>
> Alan wrote:
>
> > My 87FC35 has a 8.0 kW genset. I am getting low voltage out of it
> > (around 95 volts). On my last onan genset (77 GMC - carbed gas),
> > this was a common problem and was simply corrected by increasing
> > RPMs. (If this is the fix, how do I adjust idle speed? This fuel
> > injection isn't as intuitive for me as I've been a carburetor
guy.)
> >
> > I found an installation manual for the genset and it says to
adjust
> > some "taps" on a transformer regulator. It also says "output
> > frequency is determined by engine speed and normally does not
> > require adjustment." I'm not exactly sure what it means by "output
> > frequency". Is that voltage??
> >
> > Is this problem more complicated than adjusting the RPMs? Maybe I
> > don't have one of the Onan manuals..?? I have a parts manual and
an
> > installation manual.
> >
> > I have searched the forums and did not find a post that seemed to
> > address my situation. Let me know if I missed it.
> >
> > Thanks in advance,
> > Alan Johnson
> > 87FC35
> >
> >
>

[one_dusty_hoot]

It could be that your govenor is not functioning.
It is a mechanical device with springs and
counter weights.

Att no load, listen to the motor judging it's
speed with your ear. Have someone turn on an
air conditioner. The motor sound will decrease
momentarily then return to the previous speed.
If it does your govenor is working, if it don't,
well...

Voltage output will be reduced with an increased
load without a govenor.

Bob Janes '87FC35 Greenville, SC

--- In WanderlodgeForum@yahoogroups.com, "Alan"
wrote:
>
> My 87FC35 has a 8.0 kW genset. I am getting low voltage out of it
> (around 95 volts). On my last onan genset (77 GMC - carbed gas),
> this was a common problem and was simply corrected by increasing
> RPMs. (If this is the fix, how do I adjust idle speed? This fuel
> injection isn't as intuitive for me as I've been a carburetor guy.)
>
> I found an installation manual for the genset and it says to adjust
> some "taps" on a transformer regulator. It also says "output
> frequency is determined by engine speed and normally does not
> require adjustment." I'm not exactly sure what it means by "output
> frequency". Is that voltage??
>
> Is this problem more complicated than adjusting the RPMs? Maybe I
> don't have one of the Onan manuals..?? I have a parts manual and
an
> installation manual.
>
> I have searched the forums and did not find a post that seemed to
> address my situation. Let me know if I missed it.
>
> Thanks in advance,
> Alan Johnson
> 87FC35
>

[John Suter]

Alan, we (the group) are assuming the low voltage you
report is equally low for both legs. If not, advise
the as we might have to modify the advice.

John Suter


--- one_dusty_hoot wrote:

> Alan, the genset puts out 2 cycles per revolution,it
> should run at 1800 rpm, govenor controlled. This
> would
> output 1800 X 2=60 cycles per second. As load is
> increased, the speed decreases, then more fuel is
> given by the govenor to maintain speed.
>
> Look at the governor next on the motor, there is an
> arm that goes against a stop when the generator is
> started. There at the stop point is the speed
> adjustment.
>
> Before you start adjusting the stop you need to know
> what speed your motor is turning. You can buy a
> vibration tachometer at small motor repair shops.
> You can move the wand in and out by turning the
> knob. When the harmonic frequency is reached, the
> extended arm will begin vibrating rapidly. Mayve
> $20?
>
> Do not attempt to adjust speed without something as
> a reference.
>
> Your problem may be that the motor is running sour,
> could be the air filter is clogged, and possibly not
> enough diesel by a dirty filter?
>
> Bob Janes 87FC35 Greenville, SC
>
>
>
>
> --- In WanderlodgeForum@yahoogroups.com, Curt
> Sprenger
> wrote:
> >
> > I'm not an expert but found this on the Internet.
> For an
> oscillating or
> > varying current, frequency is the number of
> complete cycles per
> second
> > in alternating current direction. The standard
> unit of frequency is
> the
> > hertz, abbreviated Hz. If a current completes one
> cycle per second,
> then
> > the frequency is 1 Hz; 60 cycles per second equals
> 60 Hz (the
> standard
> > alternating-current utility frequency in the
> United States).
> >
> > I recall the Onan guy adjusting rpms on our
> previous gen. set to
> get the
> > frequency to 60 and to increase voltage.
> >
> > Sounds to me you are on the right track. If you
> can, turn up the
> rpms
> > and watch for voltage increase. Good luck. Please
> keep us posted.
> >
> > Curt Sprenger 1987 PT38, Anaheim Hills, Calif.
> >
> >
> >
> > Alan wrote:
> >
> > > My 87FC35 has a 8.0 kW genset. I am getting low
> voltage out of it
> > > (around 95 volts). On my last onan genset (77
> GMC - carbed gas),
> > > this was a common problem and was simply
> corrected by increasing
> > > RPMs. (If this is the fix, how do I adjust idle
> speed? This fuel
> > > injection isn't as intuitive for me as I've been
> a carburetor
> guy.)
> > >
> > > I found an installation manual for the genset
> and it says to
> adjust
> > > some "taps" on a transformer regulator. It also
> says "output
> > > frequency is determined by engine speed and
> normally does not
> > > require adjustment." I'm not exactly sure what
> it means by "output
> > > frequency". Is that voltage??
> > >
> > > Is this problem more complicated than adjusting
> the RPMs? Maybe I
> > > don't have one of the Onan manuals..?? I have a
> parts manual and
> an
> > > installation manual.
> > >
> > > I have searched the forums and did not find a
> post that seemed to
> > > address my situation. Let me know if I missed
> it.
> > >
> > > Thanks in advance,
> > > Alan Johnson
> > > 87FC35
> > >
> > >
> >
>
>
>
>
>


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[Bruce Morris]

Be careful when you start adjusting a generator. It requires special equipment
and knowledge to do it correctly. A lot of generators run at 1800 rpm and use
rpm to determine the 60 hz (Onans are generally set at 58 hz). There is also a
tool that will put a load on the generator. It is mostly a bunch of heating
coils that can be added to or removed from the generator output by different
switches. This allows the generator to be adjusted over a range of loads.

My Kohler has a voltage regulator on it that was replaced by Ralph F which is
what determines the voltage output to the coach.

Be careful adjusting generators unless you know what you are doing or you can
really mess things up without really trying.

Bruce Morris (919)872-7635 Raleigh, NC
Webmaster - WOO (http://www.wanderlodge.us)
1983 WL FC35RB

FMCA: 7142s Ham Radio: KI4ME
Vietnam Vet - 1966-67 'Doc' (Navy Corpsman) 3rd MarDiv

----- Original Message -----
From: Pete Masterson
To: WanderlodgeForum@yahoogroups.com
Sent: Tuesday, August 22, 2006 12:37 PM
Subject: Re: [WanderlodgeForum] Low voltage out of Genset


I'd suggest using a Hertz meter as well. You don't want to move the
Hz too far from 60 as it can adversely affect motors, etc.

Pete Masterson
aeonix1@...
'95 Bluebird Wanderlodge WBDA 4203
El Sobrante, CA

On Aug 22, 2006, at 8:14 AM, Curt Sprenger wrote:

> I'm not an expert but found this on the Internet. For an
> oscillating or
> varying current, frequency is the number of complete cycles per second
> in alternating current direction. The standard unit of frequency is
> the
> hertz, abbreviated Hz. If a current completes one cycle per second,
> then
> the frequency is 1 Hz; 60 cycles per second equals 60 Hz (the standard
> alternating-current utility frequency in the United States).
>
> I recall the Onan guy adjusting rpms on our previous gen. set to
> get the
> frequency to 60 and to increase voltage.
>
> Sounds to me you are on the right track. If you can, turn up the rpms
> and watch for voltage increase. Good luck. Please keep us posted.
>
> Curt Sprenger 1987 PT38, Anaheim Hills, Calif.
>
>
>
> Alan wrote:
>
>> My 87FC35 has a 8.0 kW genset. I am getting low voltage out of it
>> (around 95 volts). On my last onan genset (77 GMC - carbed gas),
>> this was a common problem and was simply corrected by increasing
>> RPMs. (If this is the fix, how do I adjust idle speed? This fuel
>> injection isn't as intuitive for me as I've been a carburetor guy.)
>>
>> I found an installation manual for the genset and it says to adjust
>> some "taps" on a transformer regulator. It also says "output
>> frequency is determined by engine speed and normally does not
>> require adjustment." I'm not exactly sure what it means by "output
>> frequency". Is that voltage??
>>
>> Is this problem more complicated than adjusting the RPMs? Maybe I
>> don't have one of the Onan manuals..?? I have a parts manual and an
>> installation manual.
>>
>> I have searched the forums and did not find a post that seemed to
>> address my situation. Let me know if I missed it.
>>
>> Thanks in advance,
>> Alan Johnson
>> 87FC35
>>
>>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>

[Non-text portions of this message have been removed]





[Non-text portions of this message have been removed]

[one_dusty_hoot]

John, excellent point, "assume" can get one
into a lot of trouble. And yes, I was assuming
that both leg voltages were nearly equal.

But...Suppose leg 1 had a normal voltage reading
of 120 VAC and leg 2 read the 95 VAC. Then it
is possible because of heavy load on leg 2, maybe
a hi-amp charge rate, or, dragging AC motor, the
additional current requirement has decreased the
voltage to 95 VAC and the genset is fine.

The only assumption that can safely be made is
that it did operate properly at one time.

Alan, give us some more infomation on the voltage
using a multimeter. Could be a defective gage as
well?

Bob Janes '87FC35 Greenville, SC


--- In WanderlodgeForum@yahoogroups.com, John Suter
wrote:
>
> Alan, we (the group) are assuming the low voltage you
> report is equally low for both legs. If not, advise
> the as we might have to modify the advice.
>
> John Suter
>
>
> --- one_dusty_hoot wrote:
>
> > Alan, the genset puts out 2 cycles per revolution,it
> > should run at 1800 rpm, govenor controlled. This
> > would
> > output 1800 X 2=60 cycles per second. As load is
> > increased, the speed decreases, then more fuel is
> > given by the govenor to maintain speed.
> >
> > Look at the governor next on the motor, there is an
> > arm that goes against a stop when the generator is
> > started. There at the stop point is the speed
> > adjustment.
> >
> > Before you start adjusting the stop you need to know
> > what speed your motor is turning. You can buy a
> > vibration tachometer at small motor repair shops.
> > You can move the wand in and out by turning the
> > knob. When the harmonic frequency is reached, the
> > extended arm will begin vibrating rapidly. Mayve
> > $20?
> >
> > Do not attempt to adjust speed without something as
> > a reference.
> >
> > Your problem may be that the motor is running sour,
> > could be the air filter is clogged, and possibly not
> > enough diesel by a dirty filter?
> >
> > Bob Janes 87FC35 Greenville, SC
> >
> >
> >
> >
> > --- In WanderlodgeForum@yahoogroups.com, Curt
> > Sprenger
> > wrote:
> > >
> > > I'm not an expert but found this on the Internet.
> > For an
> > oscillating or
> > > varying current, frequency is the number of
> > complete cycles per
> > second
> > > in alternating current direction. The standard
> > unit of frequency is
> > the
> > > hertz, abbreviated Hz. If a current completes one
> > cycle per second,
> > then
> > > the frequency is 1 Hz; 60 cycles per second equals
> > 60 Hz (the
> > standard
> > > alternating-current utility frequency in the
> > United States).
> > >
> > > I recall the Onan guy adjusting rpms on our
> > previous gen. set to
> > get the
> > > frequency to 60 and to increase voltage.
> > >
> > > Sounds to me you are on the right track. If you
> > can, turn up the
> > rpms
> > > and watch for voltage increase. Good luck. Please
> > keep us posted.
> > >
> > > Curt Sprenger 1987 PT38, Anaheim Hills, Calif.
> > >
> > >
> > >
> > > Alan wrote:
> > >
> > > > My 87FC35 has a 8.0 kW genset. I am getting low
> > voltage out of it
> > > > (around 95 volts). On my last onan genset (77
> > GMC - carbed gas),
> > > > this was a common problem and was simply
> > corrected by increasing
> > > > RPMs. (If this is the fix, how do I adjust idle
> > speed? This fuel
> > > > injection isn't as intuitive for me as I've been
> > a carburetor
> > guy.)
> > > >
> > > > I found an installation manual for the genset
> > and it says to
> > adjust
> > > > some "taps" on a transformer regulator. It also
> > says "output
> > > > frequency is determined by engine speed and
> > normally does not
> > > > require adjustment." I'm not exactly sure what
> > it means by "output
> > > > frequency". Is that voltage??
> > > >
> > > > Is this problem more complicated than adjusting
> > the RPMs? Maybe I
> > > > don't have one of the Onan manuals..?? I have a
> > parts manual and
> > an
> > > > installation manual.
> > > >
> > > > I have searched the forums and did not find a
> > post that seemed to
> > > > address my situation. Let me know if I missed
> > it.
> > > >
> > > > Thanks in advance,
> > > > Alan Johnson
> > > > 87FC35
> > > >
> > > >
> > >
> >
> >
> >
> >
> >
>
>
> __________________________________________________
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam protection around
> http://mail.yahoo.com
>

[Alan]

Ok, here are my findings so far.

1. Engine RPMs - right at 1800 (I bought a vibration tach, as
suggested.)
2. Frequency stays right between 59.5 and 60.5 whether under heavy
load or not.

Leg 1 Leg 2
------ ------
No (very little) load 108v 108v
Front a/c only 104.5 110
Both a/c's on 104 101.5
Rear a/c only 100 91 (a/c compressor is having
trouble running)

When on shore power I've got right at 120v. On the generator, I'm
obviously low on voltage all the time, but do these different
readings tell you guys anything? Do I just need to up the rpms, or
will that mess up my frequency??

Thanks!
Alan Johnson
87FC35






--- In WanderlodgeForum@yahoogroups.com, "Alan"
wrote:
>
> My 87FC35 has a 8.0 kW genset. I am getting low voltage out of it
> (around 95 volts). On my last onan genset (77 GMC - carbed gas),
> this was a common problem and was simply corrected by increasing
> RPMs. (If this is the fix, how do I adjust idle speed? This fuel
> injection isn't as intuitive for me as I've been a carburetor guy.)
>
> I found an installation manual for the genset and it says to
adjust
> some "taps" on a transformer regulator. It also says "output
> frequency is determined by engine speed and normally does not
> require adjustment." I'm not exactly sure what it means
by "output
> frequency". Is that voltage??
>
> Is this problem more complicated than adjusting the RPMs? Maybe I
> don't have one of the Onan manuals..?? I have a parts manual and
an
> installation manual.
>
> I have searched the forums and did not find a post that seemed to
> address my situation. Let me know if I missed it.
>
> Thanks in advance,
> Alan Johnson
> 87FC35
>