MEP-806A Low voltage/ low frequency problem ??

[DieselAddict]

Nice. Congrats!

 

[1800 Diesel]

OK Boys and Girls !! I got this figured out ! Ok a old friend came over with a tach to see what the engine is doing. We put the tape on the balancer. fire it up and it was running 1550 to 1625 RPM . Still have low frequency and voltage. I went to go get a small screw driver and just before I was going to adjust the frequency the engine stumbled twice then the rpm jumped up to 1800 RPM by itself . Oddly for a moment the frequency and voltage were still low . Then the generator did a self flash ! and boom everything was reading correctly !! so after turning it back off then back on. it runs for a min then it self flashes itself . So for it to do this the RPM needs to be at 1800 . So that's why it wouldn't work before. Even doing it manually flash before it wouldn't because the RPM were to low.

R Racing,

Edit--I mistakenly thought this was the other post on the MEP-004A...my mistake & original reply has been deleted. Sorry for the mix-up. Interestingly though, later today I took a quick look at the TM for your generator and realized that some of my original comments may also apply to the 806A. In the 24 TM I noticed the field flash magnetic contact should close somewhere near 900 RPM, so you may have something going out on the magnetic pickup that senses speed for both the cranking circuit disconnect and the field flash connect after start-up. Even at the lower RPMs you measured prior to the engine speed coming up to 1800 RPM, the field should have been flashed (with near proper voltage showing but frequency lower than 60hz). I have no hands-on experience with that model but if these sets behave per the TM, the engine speeds your friend measured should not have been a cause for a no-flash.

Also on the unexplained speed changes you're seeing, you may have some air or water in the fuel system causing that to happen. If you haven't drained the filter housings lately or changed fuel filters lately, both of these may be in order.

 

[R Racing]

Well after not starting this Gen for more than 2 months I'm having a similar issue again? The difference this time is the RPM is up at 1800 + with the knob I can turn it up to 2000 RPM . I can manually flash the gen, But as soon as I let go of the start switch the power and freq drop ??? any thoughts?

 

[R Racing]

Ok I have a update. 1 of the things I read in the manual talked about the magnetic pickup switch to show the control proper RPM for a flash. So I pulled the 1 connector out to measure resistance. went to remove the second 1 it wouldn't budge. after some brute force it came apart and it was corroded badly. after some cleaning up It ohmed good ( between 800 and 1100 ohms). and using the dead crank switch Its supposed to read between 2-3 volts AC I was getting 3.0 to 3.6 VAC. went to crank it up and everything works as it should. Maybe a coincidence . but its working !!

 

[Ray70]

Hello R Racing, I was just reading this post and wondering if your 806B is still working properly? If so, the magnetic pickup ended up being the problem?

 

[R Racing]

Hello R Racing, I was just reading this post and wondering if your 806B is still working properly? If so, the magnetic pickup ended up being the problem?

Unfortunately I believe I have a bad controller box. I still have the same problem. By the way it's a 806A . I'm saving up for a new control box

 

[Guyfang]

The problem, as described above, could never have been the mag pickup. It could only have been a governor problem. And if your mag pickup still reads 3.6, you need to screw it back out. The book reads, and you wrote, 2-3 volts AC. The danger to your mag pickup is not too high voltage. It that it's way to close to the ring gear. If you grind the end off, thats not good. Also, the ring gear can build up oil, and metal filings. When the mag pickup gets covered in that crud, it stops working properly.

Any time you get proper excitation with the S1, and voltage drops off when you let go of S1, the volt regulater is 99% the cause.

 

[Guyfang]

Hello R Racing, I was just reading this post and wondering if your 806B is still working properly? If so, the magnetic pickup ended up being the problem?

you are comparing apples and oranges. The differences between the A & B models is great.

 

[MMckearney]

Do you have the electrical drawing for this governor?

 

[Guyfang]

What governor? What gen set?

 

[MMckearney]

I need a tech manual for a Governors America Corp esd5560 (P/N 88-22850-30)

 

[Guyfang]

There is no tech manual for any governor. I do have some info for the many different gov, for the many different types of gen set. But they are listed by NSN, and if I have to look up all of them, it will be later tonight. Tell me what kind of gen set, what model, then I can find it much faster.

 

[MMckearney]

There is no tech manual for any governor. I do have some info for the many different gov, for the many different types of gen set. But they are listed by NSN, and if I have to look up all of them, it will be later tonight. Tell me what kind of gen set, what model, then I can find it much faster.

MEP 806a. If you come across info on woodward (DYNA-CONTROLLER PART NUMBER 8270-1010) or barber coleman (DYNA 10502-003-0-24) versions of this speed controller it should be identical. I attached some info on it that you have already posted. I believe this is the same governor for 804a/805a models
View attachment 88-22850-30 SCU (15-60KW A Model A5 GCU Adj).pdf

 

[Guyfang]

Indeed, it fits them all, and that's all the info I have. The manufactures, will not give out more then that to the unwashed masses. To CECOM, maybe. I will try a source, but he is moving right now, don't know if he has the time to help, if he even can.

What do you need/want?

 

[kpcxn393]

Hello everyone　
I also had a similar problem with low voltage, so I solved itI will write solution.
Turn the start switch for 3 ~ 5 seconds
It has started successfully.
Maybe the start switch was bad
I'm glad if you can use it as a reference

This thread helped me. Thank you very much!

 

[R Racing]

The problem, as described above, could never have been the mag pickup. It could only have been a governor problem. And if your mag pickup still reads 3.6, you need to screw it back out. The book reads, and you wrote, 2-3 volts AC. The danger to your mag pickup is not too high voltage. It that it's way to close to the ring gear. If you grind the end off, thats not good. Also, the ring gear can build up oil, and metal filings. When the mag pickup gets covered in that crud, it stops working properly.

Any time you get proper excitation with the S1, and voltage drops off when you let go of S1, the volt regulater is 99% the cause.

Well I have finally ordered a replacement voltage regulator for this Gen. I'll post a update once I receive it and have it installed. question is this considered a weak link or high failure item on these generators? how about the blue box governors ?

 

[MMckearney]

MEP 806a. If you come across info on woodward (DYNA-CONTROLLER PART NUMBER 8270-1010) or barber coleman (DYNA 10502-003-0-24) versions of this speed controller it should be identical. I attached some info on it that you have already posted. I believe this is the same governor for 804a/805a models
View attachment 737071

Governors America Corp (GAC) speed control unit 88-22850-60 fits both applications (GAC P/N ESD5560). P/N 88-22850-30 and 88-22850-15 are identical units from GAC, just separate part numbers for 30kW and 15kW sets.

NSN: 2990‐01‐601‐2476
• Description:
– Universal diesel engine speed governor
that replaces Woodward NSNs:
• 2910‐01‐368‐7644 (DOD p/n 88‐21860)
• 2910‐01‐373‐2590 (DOD p/n 88‐21858 )
• 2910‐01‐368‐9883 (DOD p/n 88‐21856)

 

[R Racing]

Governors America Corp (GAC) speed control unit 88-22850-60 fits both applications (GAC P/N ESD5560). P/N 88-22850-30 and 88-22850-15 are identical units from GAC, just separate part numbers for 30kW and 15kW sets.

NSN: 2990‐01‐601‐2476
• Description:
– Universal diesel engine speed governor
that replaces Woodward NSNs:
• 2910‐01‐368‐7644 (DOD p/n 88‐21860)
• 2910‐01‐373‐2590 (DOD p/n 88‐21858 )
• 2910‐01‐368‐9883 (DOD p/n 88‐21856)

ok found something very interesting today! the 400 hz regulator and the 60hz regulator use the same internal boards , and transformers. the big difference is resistor values and some capacitors and resistors added , and some not there. it appears to me you could take the 400 hz board and swap resistors from the 60 hz board. and 4 capacitors and make it a 60hz board. the boards even share the same part numbers. the 1st picture is the 60 hz board. the 2and is the 400 hz board.

 

[R Racing]

ok found something very interesting today! the 400 hz regulator and the 60hz regulator use the same internal boards , and transformers. the big difference is resistor values and some capacitors and resistors added , and some not there. it appears to me you could take the 400 hz board and swap resistors from the 60 hz board. and 4 capacitors and make it a 60hz board. the boards even share the same part numbers. the 1st picture is the 60 hz board. the 2and is the 400 hz board.

sorry pi led the wrong pictures. let's try this again.

 

[R Racing]

sorry pi led the wrong pictures. let's try this again.

pictures of the transformers. 1st picture is 60 hz. 2and is 400 h