mep 803a power at lugs one time

[Walter J Riedel]

I am having an issue with power at lugs. New to me generator with 21 hrs on meter, no reset mod, 2005 year model. Professional wired to house. Started it and no power at lugs.
Opened unit and looked for loose wires . Found loose wire at K20. Started unit again and S5 switch worked and powered whole house for 4 hours. Days later no power when S5 raised. Have since read many threads and tested S5, K1. No issues. Found i have no power from S8 to K1 on B1 wire when running. There is power on all other terminals on S8. Should all B's have 110 when selector set to 120/240 single phase? Have used DeoxIT on S8 but still the same. Another issue is negative reading on ammeter. Tested alternator, output 47 volts. Have 50mv at back of gauge. Hope this information is enough to start.

 

[csheath]

Are you remembering to toggle the Circuit Interrupter switch closed after you start it?

 

[kloppk]

Test the Contactor Closed Lamp to verify it's working. To do so put S1 in Prime/Run and press on the lamp lens to verify it illuminates.
With the set running and HOLDING S5 up does the contactor lamp illuminate?

 

[Walter J Riedel]

Yes I close the switch and nothing. And yes the contactor light does test good.

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[Guyfang]

Place marker.

 

[kloppk]

I assume when you say "nothing" it means the contactor lamp did NOT illuminate.
So....

1) When you had the set running where there any Fault lamps illuminated. If unsure restart the set and verify no Fault lamps are illuminated. Are they all off?

2) Test the Fault Monitor by putting S1 in Prime Run and depress the TEST button on the Fault Monitor and verify all the lamps illuminate.

You'll need a hand held voltmeter to take some DC voltage measurements.
3) Open the gauge panel
4) Set you meter to DC volts
5) Connect your meters negative lead to the ground stud in the right corner of the gauge panel.
6) Start the generator
7) Measure the DC voltage at S5 terminals 2, 3 & 5. All three terminals should be ~ 24 volts DC. Are they?
8.) Measure the DC voltage at S5 terminal 6. It should be 0 volts DC. Is it?
9) Now connect your meters positive lead to S5-5.
10) While watching the meter lift S5 up and see if the DC voltage goes from ~24 volts DC to 0 volts DC when S5 is lifted UP. Does it?

 

[Walter J Riedel]

Terminal 5 on S5 has no voltage.

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[Guyfang]

Before or after steps 7-10?

7) Measure the DC voltage at S5 terminals 2, 3 & 5. All three terminals should be ~ 24 volts DC. Are they?
8.) Measure the DC voltage at S5 terminal 6. It should be 0 volts DC. Is it?
9) Now connect your meters positive lead to S5-5.
10) While watching the meter lift S5 up and see if the DC voltage goes from ~24 volts DC to 0 volts DC when S5 is lifted UP. Does it?

 

[Walter J Riedel]

No voltage at step 7 on 5. No voltage on step 8 on 6. No change to voltage on step 10.

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[kloppk]

If no 24 volts at S5-5 with the set running then there is a problem with the 24 volts getting from K20 the Oil Pressure relay all the way to S5-5.

Here is the path from K20-6 all the way to S5-5. With the set running start at K20-6 verify 24 volts DC is there and continue down the path until you lose 24 volts.

K20-6---Wire 150D---TB5-19---Wire150E---J6-29/P6-29---Wire 150B---K1-X-K1Coil-K1-Y---Wire152D---P6-35/J6-35---Wire 152C---TB5-16---Wire 152B---S5-5

 

[Walter J Riedel]

Where is TB5 and J 6/P6?

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[Walter J Riedel]

J6 is as screw plug?

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[kloppk]

TB5 is the long terminal strip behind the row of relays

J6 Visible in this pic. P6 is plugged into it from underneath the compartment.

 

[Walter J Riedel]

I got TB5

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[Walter J Riedel]

So I have to unplug J6 and test while running?

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[kloppk]

Leave it plugged in and check all the other points along the path.
If what you get for measurements points to a P6/J6 problem then we'll need to do some resistance checks with the set OFF.

 

[Walter J Riedel]

It could still be J6.

 

[kloppk]

I you had 24 volts at K1-Y and nothing at TB5-16 then it could be a problem with the connection between P6 & J6.
With the set OFF and Dead Crank in OFF unplug P6 from J6. Access from the right door under the gauge panel.
You'll need to turn the locking collar on P6 CCW to unlock it before you can remove P6 from J6.

Examine the contacts in P6 & J6. Focus on pin 35. If no corrosion then you'll want to use you meter to check for continuity between K1-Y and P6-35. Then check for continuity between J6-35 and TB5-16.

 

[Walter J Riedel]

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[kloppk]

Do you mean no continuity between TB5-16 and J6-35?