MEP 805A Libby Voltage Reg. Retrofit

[Capt.Moondog]

Has anyone bought and retrofitted a MEP 805A generator from TRC to Libby with a Libby retrofit kit.
there is one on eBay and been having problems with my hertz jumping around won’t stay on 60 just jumps back to 50 not sure what all needs to be changed but I’m in the mood to throw every part known to mankind at this thing to get it running smoothly!
I seen somewhere but can’t find it again that Libby is a better system so just figured while I was chasing generator issues I would change it out just in case I’ll send picture of the one on ebay

 

[Light in the Dark]

Is it the hertz gauge that's moving around, or is the sound of the engine actually changing rpm (and thus changing what the gauge displays)? An important distinction.

 

[Capt.Moondog]

Well I changed out the hertz meter to make sure It wasn’t that but yes the motor itself changes in rpm just a touch and the hertz meter jumps from 60 to 50

 

[kloppk]

Might want to check the frequency with an external device such as a DMM that can measure frequency or a Kill-a-Watt meter.
That way you'll know if it's engine RPM or a bad transducer.

 

[Capt.Moondog]

Ok so if the transducer is bad or going bad it will make the rpm change?
Also I was wondering if it’s worth the weight and gold to change to a Libby system for the voltage regulator. I know it’s not part of the problem I’m having now but was thinking since I’m in there and in the mode would it be worth my time

 

[kloppk]

To switch systems you have to relpace the regulator, T1 transformer, front panel voltage adjuster and resistor R16 on the back of the freq select switch.

 

[Light in the Dark]

I'm not familiar with this machine, but I am assuming its mechanically governed like the smaller sets (not electronically governed). If that assumption is true, no controls play part in RPM shift.

 

[Capt.Moondog]

 

[Capt.Moondog]

In that picture is the electric controlled governor so not sure if this part is the problem or not would you know what controls this could it be this part or whatever is telling it what to do

 

[kloppk]

Basically the operation is the Magnetic Pickup (MPU) sensor on the bell housing detects the engine RPM. The Electronic Governor Controller (A5) measures output signal from the MPU to determine the actual engine RPM. The Electronic Governor Controller then adjusts the signal it sends to the electronic actuator (A6) to adjust the engine RPM as needed. The Electronic Governor Controller in mounted on the back wall behind the gauge panel.
The frequency select switch tells which frequency the Governor Controller is supposed to maintain 50 or 60 Hz.
R2 is the fine frequency adjust.

 

[Guyfang]

You wrote:
Has anyone bought and retrofitted a MEP 805A generator from TRC to Libby with a Libby retrofit kit.
there is one on eBay and been having problems with my hertz jumping around won’t stay on 60 just jumps back to 50 not sure what all needs to be changed but I’m in the mood to throw every part known to mankind at this thing to get it running smoothly!
I seen somewhere but can’t find it again that Libby is a better system so just figured while I was chasing generator issues I would change it out just in case I’ll send picture of the one on ebay

Nothing in that kit would have anything to do with Speed control. See the attachment. Check to see if your GCU is mal adjusted first, before you do any knob dicking.

 

[Ray70]

If you're looking to change out the regulator ( for whatever reason ) I'd go with @kloppk's replacement regulator instead of all the hassle of switching from the TRC to Libby.
I used it on an 806 and worked perfectly, dropped right in and it bypasses the mouse-urinal of a transformer in the machine I was working on!
Cheaper, easier and more reliable, pretty much a no brainer.

 

[Capt.Moondog]

Thanks to everyone’s support!! I’ll check the above suggestions and also look into the bypass idea! Thanks again

 

[Capt.Moondog]

Color me stupid, here I am again!!

I got the courage to dive into the gremlins again and cranked up the 805a again everything works perfectly except the hertz would not work on 60h and so I started adjusting the freq. CW and got it to run on 60 hertz I also had to adjust the over speed a touch from keeping it from shutting down. All worked well but the battery charger gauge runs up to 10+right after cranking and slowly creeps down to 0 volts ? But the machine runs and produces electricity I had a heater plugged in and a extra volt meter to check everything, but about every 5 minutes it has strange surges and hits the over speed limit and shuts off .
I shut machine off and reset several times and it still continues to do it after about 5 minutes.

I then shut machine off and switched the hertz meter to 50 to just see what would happen and it stays on 60h! So it appears the machine is stuck in the 50 hertz mode and all I did was adjust the frequency to 60 with it in that mode!
Any suggestions on where to place the dynamite or parts to change or steps to take from here?
Anything is appreciated
I took a picture of back side of hertz switch just for a reference sake just in case there is something obvious with the wireing due to previous owner definitely did a better job dicking with it than me as suggested earlier

Rusty

 

[Guyfang]

Rusty.
You need to get your TM's out and read. The 50 hertz switch. I hope you did not switch it back and forth while running? Bad things can happen when you do that.

By "would not work on 60h and so I started adjusting the freq. CW and got it to run on 60 hertz I also had to adjust the over speed a touch from keeping it from shutting down. " Where did you do this adjusting? Was it in 50 05 60 hertz mode?

"All worked well but the battery charger gauge runs up to 10+right after cranking and slowly creeps down to 0 volts"
This is how it normally works. You deplete the battery level on start up, so the battery charging circuit sees this and cranks up the juice a bit, to top the batter off. Then the charging circuit senses the batteries full, and cranks the juice back down. Over charging a battery is not goo. So this is a non problem.


In the picture, I see a screw missing from the S12, The Frequency selector switch. I also see a screw on the bottom of the control cube. Have you compared the S12 to the wire diagram, to see if its wired correctly? Also you need to check R16 to see if its good.

 

[2Pbfeet]

@Guyfang Eagle eye!

 

[Capt.Moondog]

Thank you for your response and support!!

No I did not switch from 60 to 50 while machine was running! If I have learned anything from Yall I remembered you telling me earlier.
Thanks for the clarification on battery meter!

I used that page you forwarded to me on the instructions of A5 and adjusted the frequency knob on far left CW to advance the hertz up to 60 while doing that the machine picked up rpm accordingly and I hit the over speed limit and so I adjusted that knob on far right of A5 and got it running smoothly!
I was strutting around patting myself on the back and then!!! it started a sudden jump in rpm hit the overspeed limit and shut off it would do this about every 5 minutes at first so I advanced the over speed a touch and then it would surge and then go back down.
I had a heater plugged in the outlet in front and also had a volt meter checking the volts interesting enough when the machine would surge the volts would drop some and the hertz meter would go up.

This is when I shut the machine down and switch to the 50hertz cranked it back up and it was at them same hertz as before 60. “Note that before I dicked with A5 it would stay on 50hertz and could not get it to go to 60.
The picture I took was for the purpose you spotted I noticed the same screw was out and on the bottom I have not checked the diagram wiring but I will by the picture you sent.
Thanks for now I’ll let Yall know how the switch wiring is.

Rusty

 

[Capt.Moondog]

I trying but need confirmation is R16 the diode on back of frequency selector switch?

 

[kloppk]

Back of Freq switch - Yes
R16 is a Resistor, not a Diode.

 

[Capt.Moondog]

Thanks do you know right off hand where best place to buy one