Empathy List Archives

J&

Jim & Emily

Mon, Jun 14, 2004 5:56 PM

Started up my 15 KW Onan MDJF this afternoon for some exercise. This is the first time I have owned a boat with a gen-set that has a Frequency Meter and I noticed that on initial start up the Onan displayed about 61 HZ. When I put a load on it of two a/c units the frequency dropped to about 58/59 Hz (this is the vibrating type meter). Under further load of one of the burners on the electric range it dropped to 57/58 Hz. Is this normal operation for this gen-set?

Thanks,

Jim Alexander

Started up my 15 KW Onan MDJF this afternoon for some exercise. This is the first time I have owned a boat with a gen-set that has a Frequency Meter and I noticed that on initial start up the Onan displayed about 61 HZ. When I put a load on it of two a/c units the frequency dropped to about 58/59 Hz (this is the vibrating type meter). Under further load of one of the burners on the electric range it dropped to 57/58 Hz. Is this normal operation for this gen-set? Thanks, Jim Alexander

CG

Chris Grubb

Mon, Jun 14, 2004 7:04 PM

<<<<<Started up my 15 KW Onan MDJF this afternoon for some exercise. This
is the first time I have owned a boat with a gen-set that has a Frequency
Meter and I noticed that on initial start up the Onan displayed about 61 HZ.
When I put a load on it of two a/c units the frequency dropped to about
58/59 Hz (this is the vibrating type meter). Under further load of one of
the burners on the electric range it dropped to 57/58 Hz. Is this normal
operation for this gen-set?>>>>>

Jim,
Our Onan MDJB 6.0 has a frequency of 61.8 with no load @127 volts. Fully
loaded the hertz will drop to about 59+ with voltage of 117. This is about
the best I can adjust the governor. What voltage is yours running fully
loaded? Maybe you can adjust the governor a little more to achieve less of
a drop without a hunting condition (as long as the fuel filters are
clean-KISS)
I'm curious as to what others with Onans experience. We use the Kill O watt
meter for frequency testing. I've tested it against a Fluke and it's on the
money.
Listening for answers,
Chris

<<<<<Started up my 15 KW Onan MDJF this afternoon for some exercise. This is the first time I have owned a boat with a gen-set that has a Frequency Meter and I noticed that on initial start up the Onan displayed about 61 HZ. When I put a load on it of two a/c units the frequency dropped to about 58/59 Hz (this is the vibrating type meter). Under further load of one of the burners on the electric range it dropped to 57/58 Hz. Is this normal operation for this gen-set?>>>>> Jim, Our Onan MDJB 6.0 has a frequency of 61.8 with no load @127 volts. Fully loaded the hertz will drop to about 59+ with voltage of 117. This is about the best I can adjust the governor. What voltage is yours running fully loaded? Maybe you can adjust the governor a little more to achieve less of a drop without a hunting condition (as long as the fuel filters are clean-KISS) I'm curious as to what others with Onans experience. We use the Kill O watt meter for frequency testing. I've tested it against a Fluke and it's on the money. Listening for answers, Chris

RC

R C Smith Jr

Mon, Jun 14, 2004 7:28 PM

Absolutely normal...at least for a 20-yr-old genset. You are talking about
less than 2% fluctuation...not bad. However, the a/c's do not like low
frequency, so I set my gensets to run on the high side without
load...allowing them to settle in around 60Hz when working.

Bob

Robert Calhoun Smith Jr
M/V MARY KATHRYN
Hatteras 58 LRC

Jim & Emily wrote:

Started up my 15 KW Onan MDJF this afternoon for some exercise. This is the
first time I have owned a boat with a gen-set that has a Frequency Meter and I
noticed that on initial start up the Onan displayed about 61 HZ. When I put a
load on it of two a/c units the frequency dropped to about 58/59 Hz (this is
the vibrating type meter). Under further load of one of the burners on the
electric range it dropped to 57/58 Hz. Is this normal operation for this
gen-set?

Absolutely normal...at least for a 20-yr-old genset. You are talking about less than 2% fluctuation...not bad. However, the a/c's do not like low frequency, so I set my gensets to run on the high side without load...allowing them to settle in around 60Hz when working. Bob ________________ Robert Calhoun Smith Jr M/V MARY KATHRYN Hatteras 58 LRC Jim & Emily wrote: > Started up my 15 KW Onan MDJF this afternoon for some exercise. This is the > first time I have owned a boat with a gen-set that has a Frequency Meter and I > noticed that on initial start up the Onan displayed about 61 HZ. When I put a > load on it of two a/c units the frequency dropped to about 58/59 Hz (this is > the vibrating type meter). Under further load of one of the burners on the > electric range it dropped to 57/58 Hz. Is this normal operation for this > gen-set?

CW

cooke_w@bellsouth.net

Mon, Jun 14, 2004 7:37 PM

Our genset is a Phasor and its very much the same. I don't remember the
numbers exactly but I know that they don't stay static under different
loads.
I believe you will find this pretty much the case with most of the gensets
found in boats around our sizes.
Given a preference I'd want the voltage not to drop under 110-112 regardless
of freq. assuming that stayed between 55-65. The only thing a 8-10% change
in hertz will do is make your electric clocks inaccurate but a low voltage
will deal things like AC and fridge fits and if it gets too low the
compressors will overheat and could die.
Bill

Our genset is a Phasor and its very much the same. I don't remember the numbers exactly but I know that they don't stay static under different loads. I believe you will find this pretty much the case with most of the gensets found in boats around our sizes. Given a preference I'd want the voltage not to drop under 110-112 regardless of freq. assuming that stayed between 55-65. The only thing a 8-10% change in hertz will do is make your electric clocks inaccurate but a low voltage will deal things like AC and fridge fits and if it gets too low the compressors will overheat and could die. Bill

trawlers@lists.trawlering.com

Onan MDJF