Converting a MEP-831A to standard generator

OverkillTASF

Member
76
1
8
Location
Central Virginia
24 volts from the battery direct to the governor is 2.2 amps draw. That's good news in that a much smaller MOSFET than I expected can probably be used. Now to see if I've got one around here...

DA, I'm probably reinventing a lot of what you've done. Obviously a minimal step one is being able to start, run at 3600 RPM, stop the motor. Obviously the mechanical governor could be relied on to keep it at 3600 RPM, but I find myself interested in also being able to dial the RPMs down, even with a regular generator head on it. Could do something like, have the contactor shut off main power, dial back to the max-torque max-fuel efficiency RPM, and either use that (I think 40-50 hz) AC to rectify out for charging a battery bank through a charge controller fairly efficiently or doing some resistive heating or some such. Also I just want to see an arduino control something big and nasty like an military diesel generator. Heh. But I also want to do it on the super cheap... my very poor understanding of the circuitry needed to support a large enough MOSFET doing PWM off of the Arduino pins might get me there and be interesting!
 

OverkillTASF

Member
76
1
8
Location
Central Virginia
Well not that I have made much progress on anything super interesting... But had some power outages here and after hearing some gensets spinning up and seeing "no ETA for power restore", since I'm home alone with small kids I figured my manhood was at stake. I got the engine with Northstart generator head moved out to the shed, wired it in, did some real unsafe things to gravity feed fuel to the generator, and now have a really loud "whole house generator".

Setting the mechanical speed control to full speed gave me a ~61 Hz frequency under no load, it has been pretty stable. At a 27 amp / 120 volt draw, which I will call 3240 watts (refrigerators, dehumidifiers, fans, batteries charging, toaster-oven running), I get the first Hz dip. No black smoke from the generator, so it might have a little more room to grow but I don't have a great way to load test.

The enclosure is responsible for a LOT of noise savings... even inside the shed (ventilated with open eaves) it's pretty **** loud.

In any case, the proof of concept proves out so far; The engine works with the Northstar 4000 watt head but as expected probably can't make full use of it.

I could run it like this in the enclosure, but not with everything plugged in; The J7 (I think... the big one) connector is in the way. But if I move it and the hole it passes through over... I might be able to get everything back into the genset.
 

kloppk

Well-known member
Steel Soldiers Supporter
1,173
889
113
Location
Massachusetts
Yes, P7/J7 has to be relocated. Did it to my 831 with the 4K head installed. The contactor has to be relocated too.

I'll let that cat out of the bag for those that may be interested in converting their 831A to a "standard" generator head such as the Northstar 4000 watt head.
I'm developing a smart Governor Controller replacement to support using a "standard" gen head.
The new controller will:
- Control engine RPM to maintain the frequency to better that 60 +/- 0.2 Hz from 0% load to 100% load.
- Restores Overload protection function so that the 831's contactor will open after a sustained overload condition for more than "x" seconds. It will do this if EITHER leg of the gen head is overloaded.
- Re-purposes the existing Killowatt load meter as an ammeter. It displays the load current on the two output legs of the gen head. The current load displayed on the meter is the larger of the two current loads on the two gen head legs.

The plan is to be able to produce controllers, a plug and play wire harness and installation instruction for the complete conversion. No wire harness modifications to make to install it.

Status of the development effort:
I have an 831 with the Northstar 4K head installed
Working prototype of the new controller. (Final version will incorporate jumpers and additional components.
60 Hz maintained within 0.2 Hz
Plug-n-play harness working
Overload contactor control working.

20190722_155419.jpg20190722_155448.jpg20190722_155533.jpg
 

Attachments

Last edited:

Guyfang

Well-known member
9,780
5,075
113
Location
Burgkunstadt, Germany
Yes, P7/J7 has to be relocated. Did it to my 831 with the 4K head installed. The contactor has to be relocated too.

I'll let that cat out of the bag for those that may be interested in converting their 831A to a "standard" generator head such as the Northstar 4000 watt head.
I'm developing a smart Governor Controller replacement to support using a "standard" gen head.
The new controller will:
- Control engine RPM to maintain the frequency to better that 60 +/- 0.2 Hz from 0% load to 100% load.
- Restores Overload protection function so that the 831's contactor will open after a sustained overload condition for more than "x" seconds. It will do this if EITHER leg of the gen head is overloaded.
- Re-purposes the existing Killowatt load meter as an ammeter. It displays the load current on the two output legs of the gen head. The current load displayed on the meter is the larger of the two current loads on the two gen head legs.

The plan is to be able to produce controllers, a plug and play wire harness and installation instruction for the complete conversion. No wire harness modifications to make to install it.

Status of the development effort:
I have an 831 with the Northstar 4K head installed
Working prototype of the new controller. (Final version will incorporate jumpers and additional components.
60 Hz maintained within 0.2 Hz
Plug-n-play harness working
Overload contactor control working.

View attachment 771213View attachment 771214View attachment 771215
We really need to talk about someone reverse engineering things for the MEP-002A through to MEP-006A. Know anyone who might be interested?
 

OverkillTASF

Member
76
1
8
Location
Central Virginia
Yes, P7/J7 has to be relocated. Did it to my 831 with the 4K head installed. The contactor has to be relocated too.
I'm developing a smart Governor Controller replacement to support using a "standard" gen head.
**** YEAH brother. I was planning on slowly figuring out how to restore most of the functionality, but I am somewhat electronics stupid. "Let me know if you need any additional testers", of course. Heh

In addition to making everything built-in work, I wanted to add and think about and possibly blow up my whole house by considering:

- Remote start / shutdown.
- Remote monitoring
- "low idle" function - If no load for some period of time, open contactor, throttle down. When load detected again (possibly based on resistivity of load side?), get back to 60 Hz, close contactor. Additionally there may be some low-load functions where the frequency isn't so crucial? Running incandescent lights? Rectifying the AC and hooking it up to a charge controller for a battery bank?
- Shouldn't it be possible to sync two MEPs set up this way and parallel their outputs?

I'm curious what you did with the alternator and battery charger? Seems silly to buy a ****ty $100 24 volt battery charger and then plugging that in...

CallMeColt said:
Not sure if this will help you at all but I did a build off an old MEP-501A engine
It does help me feel like less of a crazy person! I might have missed it... Was the solenoid on the fuel pump an easier cutoff than something to close the throttle?
 

OverkillTASF

Member
76
1
8
Location
Central Virginia
- Re-purposes the existing Killowatt load meter as an ammeter. It displays the load current on the two output legs of the gen head. The current load displayed on the meter is the larger of the two current loads on the two gen head legs.
What was the limitation here? If you know the current on both legs, can't you show the combined output?

Maybe leave contacts for a leg overload/imbalance indicator light or something... or a 3 way momentary toggle switch that lets you see combined versus per leg... Spitballing someone else's work of course. I think it's awesome and I'm excited for it.
 

kloppk

Well-known member
Steel Soldiers Supporter
1,173
889
113
Location
Massachusetts
What was the limitation here? If you know the current on both legs, can't you show the combined output?
Maybe leave contacts for a leg overload/imbalance indicator light or something... or a 3 way momentary toggle switch that lets you see combined versus per leg... Spitballing someone else's work of course. I think it's awesome and I'm excited for it.
The limitation at the moment is the tiny 8 pin micro controller on the present Governor Controller. It only a couple of inputs and outputs that can be utilized.
What I'm working with at present is one of my Governor Controllers and hacking it up to see if the concept will work.
Still working on tweeking the design, features and doing more live testing in my 831.
I may switch to a micro controller with more I/O to handle more features such as independent L1 L2 readings and whatever else pops up.

As for overload protection it's set up so that if there is a sustained overload on either leg it will open the contactor.
 

kloppk

Well-known member
Steel Soldiers Supporter
1,173
889
113
Location
Massachusetts
@kloppk, what did you do with the alternator and battery charger in order to still charge the battery?
I've reverse engineered the original battery charger and now produce replacements.
Will be looking at modifying that design to support the conventional gen head.
The change is the original charger uses ~50 VAC from the PMA @ 150-300 Hz. The new charger version will need to use 1 leg of the gen head output at 120 VAC & 60 Hz.
Will be crossing that bridge after I get the frequency controller design wrung out.
 

kloppk

Well-known member
Steel Soldiers Supporter
1,173
889
113
Location
Massachusetts
....- Remote start / shutdown
- Remote monitoring
I have a version of my 802/803 WiFi Remote Start and monitor system for the 831 already which includes the variable Governor Controller electronics for the the 831 with the Inverter.
Just need to re-spin the PCB into the final version and build some units.

I'd need to evaluate if it's cost effective to create a cousin to it that provides the Remote Start, Monitoring and governor functions for the replacement head fixed speed for 60 Hz.

....- "low idle" function - If no load for some period of time, open contactor, throttle down. When load detected again (possibly based on resistivity of load side?), get back to 60 Hz, close contactor.
Two issues with attempting that.
1) Not sure the voltage regulation system in the replacement gen head will tolerate being run at an RPM way less that 3600. Spec sheet for the head says 3540 - 3720 RPM.
2) It's tough to detect a light load such as LED lighting since it's not a purely resistive load. I have inverters with "sleep" functions and they cannot detect when an LED light is switched on to wake them wake up.

....Was the solenoid on the fuel pump an easier cutoff than something to close the throttle?
?? There isn't any solenoid on the 831 Fuel Pump.
The 831 shuts down the engine by dropping power to the Actuator causing it to close the throttle.


I have bigger micro controllers on their way to provide for independent measuring and reporting of the current for each leg plus room for additional features.
 

OverkillTASF

Member
76
1
8
Location
Central Virginia
I have a version of my 802/803 WiFi Remote Start and monitor system for the 831 already which includes the variable Governor Controller electronics for the the 831 with the Inverter.
Just need to re-spin the PCB into the final version and build some units.
Your signature link to those kits isn't working for me - don't have one of those generators but wanted to take a look.
I'd need to evaluate if it's cost effective to create a cousin to it that provides the Remote Start, Monitoring and governor functions for the replacement head fixed speed for 60 Hz
Man I would think it would be... the value it creates for the most commonly broken things on the MEP-831a's while turning them into a superior diesel generator, geez. But I am historically a bad estimator of the value people will see in things.
1) Not sure the voltage regulation system in the replacement gen head will tolerate being run at an RPM way less that 3600. Spec sheet for the head says 3540 - 3720 RPM.
2) It's tough to detect a light load such as LED lighting since it's not a purely resistive load. I have inverters with "sleep" functions and they cannot detect when an LED light is switched on to wake them wake up.
I hadn't considered that the voltage regulator could be damaged under no load and any RPM. Well there goes that "idea".
There isn't any solenoid on the 831 Fuel Pump.
Yeah I didn't realize CallMeColt's video was for a different generator; He added a solenoid and I wondered why he didn't use the throttle actuator or something else that controlled the throttle to shut it off. Guess adding the solenoid was easier or less expensive!
I have bigger micro controllers on their way to provide for independent measuring and reporting of the current for each leg plus room for additional features.
Awesome. And good timing. I'll put my MEP in storage until your kits are done!
 

Mogman

Well-known member
Steel Soldiers Supporter
827
580
93
Location
Papalote, TX
We really need to talk about someone reverse engineering things for the MEP-002A through to MEP-006A. Know anyone who might be interested?
I am not sure what you mean by reverse engineering, it is very easy to remove the phase switch, wire the 12 wire gen for 120/240V single phase and replace the voltage regulator with an aftermarket unit, this gets rid of virtually everything that causes problems on the gen side of the 002-003
 

Guyfang

Well-known member
9,780
5,075
113
Location
Burgkunstadt, Germany
I am not sure what you mean by reverse engineering, it is very easy to remove the phase switch, wire the 12 wire gen for 120/240V single phase and replace the voltage regulator with an aftermarket unit, this gets rid of virtually everything that causes problems on the gen side of the 002-003
I was speaking in general, but to someone specific, about the many components that are becoming hard to find. Reverse engineering the entire gen set is possible, but not cost effective. Why? It works. Its simple. Once you start to tinker on the gen set, you might as well toss out the TM's, and write your own. Everything Kurt has made, is made to work with the set, AS IS.

I do not consider the phase switch, I assume you mean the S6, Volt Reconnection Switch, to be all that big a problem. Most of the time, a simple cleaning of the switch, takes care of most problems. Dont forget, a lot of these gen sets are older then most folks in this forum. Yes, you could remove it, and simply use a terminal board. But the flexibility of the gen set is lost. Not everyone wants a straight 120/240 set. There is a bunch of things in the A.C. output box, that could, can and do go wrong with these sets. Much harder to fix or source then S6.

There is an aftermarket AC and DC volt reg for these gen sets.
 

OverkillTASF

Member
76
1
8
Location
Central Virginia
kloppk,

Did you ever finish development of your remote start compatible with standard gen heads / kit? With Winter coming, it's probably time to get my MEP out of storage and get it buttoned back together.
 

kloppk

Well-known member
Steel Soldiers Supporter
1,173
889
113
Location
Massachusetts
kloppk,

Did you ever finish development of your remote start compatible with standard gen heads / kit? With Winter coming, it's probably time to get my MEP out of storage and get it buttoned back together.
The effort stalled about a year ago when Northern Tool stopped carrying gen heads that fit the L70. I looked around off and on and haven't found a source for a suitable head until just recently. A fellow SS member found a US source of heads for a very fair price. We just installed it on his 831. Parts on order to complete the install and hope to test it all out with the existing 3,600 RPM Governor Controller design. Concurrently investigating a re-spin to that design to make it even more accurate. Prototype built awaiting test.
This effort will renew finalization of a "kit" for installing a convention gen head in an 831.

As for combining the 3,600 PRM Governor Controller with the WiFi Remote Start will be dependent on what I see for an ROI on such an effort. At the moment I don't see any demand for such a design. The sales of my existing Inverter based 831 Governor Controller / WiFi Remote Start for the 831's has been very low. Likely one for the gen head swap version would likely be way lower.
 

Mneil

New member
3
3
3
Location
MA
The effort stalled about a year ago when Northern Tool stopped carrying gen heads that fit the L70. I looked around off and on and haven't found a source for a suitable head until just recently. A fellow SS member found a US source of heads for a very fair price. We just installed it on his 831. Parts on order to complete the install and hope to test it all out with the existing 3,600 RPM Governor Controller design. Concurrently investigating a re-spin to that design to make it even more accurate. Prototype built awaiting test.
This effort will renew finalization of a "kit" for installing a convention gen head in an 831.

As for combining the 3,600 PRM Governor Controller with the WiFi Remote Start will be dependent on what I see for an ROI on such an effort. At the moment I don't see any demand for such a design. The sales of my existing Inverter based 831 Governor Controller / WiFi Remote Start for the 831's has been very low. Likely one for the gen head swap version would likely be way lower.
I just want to say that you are an amazing person and asset to this community, Kurt. You've been incredibly generous and patient, trying to reconstruct even one "good" inverter from THREE that have turned out to be bad - - no luck. And then generously helping me install a standard gen head on my 831 and dialing it. This will benefit not only me (selfishly speaking), but hopefully others out there who have found (and believe me, if you own an 831 and its "unobtainium" inverter, you WILL find out at some point when it unexpectedly goes "snap, crackle and pop") the inverter to be the key weak link over time in these otherwise amazing units. THANK YOU for all you do to help us all.
 

OverkillTASF

Member
76
1
8
Location
Central Virginia
I got the generator out of storage and finished cutting the hole for moving J7, mounted everything back up, put the muffler back on, reconnected the wires and fuel lines, rigged up a 24 volt battery with some old car batteries, and she came right to life. It has been a loooong time since I saw that running.

I was gonna start actually using it too, but... I seem to have lost the damn connector to plug into the leads coming off the head. Northern Tool is no help, and the wires are so short I don't wantto cut them and put a different connector on. Gonna have to do someresearch on that connector...

Still not sure how I'm going to keep the batteries charged. Hate the idea of buying a Genius 24 volt charger just for the gen.
 

kloppk

Well-known member
Steel Soldiers Supporter
1,173
889
113
Location
Massachusetts
If you are running two 12 volt batteries in series it's best to use two 12 volt chargers instead of a single 24 volt charger. That way the two batteries are kept balanced.

I have two Battery Tender 12V 750mA wall wart chargers that I can let go cheap. Not using them anymore. I switched to a different battery chemistry.
Two of them for $50 including shipping.
They are similar to these.. Battery Tender Chargers
 
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website like our supporting vendors. Their ads help keep Steel Soldiers going. Please consider disabling your ad blockers for the site. Thanks!

I've Disabled AdBlock
No Thanks