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Onan 6.5 MDKDP26501C output 177 Volts instead of 220


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  #1  
Old 03-18-2017, 08:25:55 PM
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Default Onan 6.5 MDKDP26501C output 177 Volts instead of 220

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Originally Posted by skip to joy
hello Harry, first i want to say hello, i am new here and my name is roman... thank you for this informative page. I am sorry for my English. I am from Austria and sometimes use a translator.. i hope everything is to understand for you.
the reason for my visit was because of searching for a wiring diagram for my generator (onan 6,5 MDKDP26501C). i use him in a formosa sailship. when i tried to start my diving comressor the onan didnt work .... on the output there are just 177 volt instead of 220.
do you have an idea what happened to my generator?
I am sorry for writing like that but I didn't find anything in the forum for an onan 6,5 mdkd. best regards, roman...(rae1968@gmx.at .... +436643431551)
This is the Onan forum: https://www.smokstak.com/forum/forumdisplay.php?f=1

I'll post this up there so that maybe someone will recognize your unit and its ailment.

skip to joy profile: https://www.smokstak.com/forum/member.php?u=105778
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Old 03-18-2017, 08:41:29 PM
Wayne 440 Wayne 440 is online now
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Default Re: Onan 6.5 MDKDP26501C output 177 Volts instead of 220

What is the rated voltage and frequency of the unit? I'm guessing maybe 220V, 50Hz.

My first move would be to check the engine speed or output frequency, if you have the means to do so.
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Old 03-18-2017, 08:47:07 PM
len k len k is offline
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Default Re: Onan 6.5 MDKDP26501C output 177 Volts instead of 220

Looks like manual number maybe 981 -0502
http://www.twinslan.net/~n0nas/manuals/onan/

Looks like YD genhead, Section 5 onward of that manual.

Interestingly they came with either electronic voltage reg or current transformer "reg". Which one do you have?
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Old 03-19-2017, 04:10:47 AM
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Default Re: Onan 6.5 MDKDP26501C output 177 Volts instead of 220

Hello len k, thank you for answering, .... yes, it's a 220v 50hz
The engine speed is like always before, .... the motor had a refit 2 years before, he runs perfect.
After switching a big load (starting a diving compressor) there was no full output anymore. Maybe you have any idea which parts I may have damaged. Thank you.

Sorry, I ment Wayne 440

Hello len k, ..... my wiring diagram numbers are
612-6184-04
And
612-6187-02
Maybe this is important for you to help me.
Thanks a lot for helping me
Best regards
Roman
(From austria)
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Old 03-19-2017, 08:12:41 AM
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Default Re: Onan 6.5 MDKDP26501C output 177 Volts instead of 220

Check the voltage regulator output. The wires should be labeled X1 and X2 or possibly F1 and F2. With the generator running t the usual speed and no load, should be around 12 to 14 volts DC (not AC).
If OK, apply some load and check again, should go up with the load.

If voltage regulator output is low, I'd suspect the voltage regulator. If high, probably a failed rotating diode.

The regulator can be rebuilt or repaired. Diodes can be purchased from an Onan parts source.
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Old 03-19-2017, 12:52:17 PM
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Default Re: Onan 6.5 MDKDP26501C output 177 Volts instead of 220

The MDKD gen end is very similar to a YD gen end physically but mostly they use transformer regulation , some have an electronic voltage regulator . The most common failure that I have seen is the bridge rectifier in the control box or especially on marine generators the exciter coil corrodes through. I would check those two things first. Cheers Dan
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