MEP-831A - Generator Head Swap?

[AfghanVeteran2010]

Sine reading yertnamreg post about doing a head swap on a Dewey Battery Charging Aux Power Unit (BAPU) Wonder if a swap with a 4kW head (NorthStar Generator Head — 4,500 Surge Watts, 4,000 Rated Watts, 9 HP Required, J609B Engine Adaption) is possible. I think since its running a diesel it should be enough for the HP requirement. The head is 11.40" in length so some of the terminal blocks would have to be moved and the contactor relocated where the inverter used to be.

What are your thoughts about this?

 

[Chainbreaker]

So you are contemplating doing this in order to eliminate the inverter? I wonder what effect it would have on fuel economy during low current use having to spin a larger mass? However the tradeoff would be more output and a more reliable genset in theory.

 

[AfghanVeteran2010]

So you are contemplating doing this in order to eliminate the inverter? I wonder what effect it would have on fuel economy during low current use having to spin a larger mass? However the tradeoff would be more output and a more reliable genset in theory.

I don't plan on doing this my self, just throwing this idea out there if anyone has a bad/missing inverter.

 

[Chainbreaker]

Also, it appears that the MEP-831 is electronically governed to run between 3000 - 3450 RPM. The NorthStar unit you are looking is spec'd for 3450 - 3720. So finding a way to run at the proper RPM would have to be dealt with.

 

[AfghanVeteran2010]

Also, it appears that the MEP-831 is electronically governed to run between 3000 - 3450 RPM. The NorthStar unit you are looking is spec'd for 3450 - 3720. So finding a way to run at the proper RPM would have to be dealt with.

Probably could achieve this by setting it up like the MEP-531a governor, or the actuator could be used to maintain 60Hz with a microcontroller kinda similar what kloppk has made for replacement SLC100's.

 

[kloppk]

... So finding a way to run at the proper RPM would have to be dealt with.

One easy way is with my governor controller. I can easily change the firmware to make the 831 run at the correct RPM based on the frequency output of the new gen head instead of the frequency output of the PMA. Simple firmware change.

 

[AfghanVeteran2010]

One easy way is with my governor controller. I can easily change the firmware to make the 831 run at the correct RPM based on the frequency output of the new gen head instead of the frequency output of the PMA. Simple firmware change.

Probably the smarter choice to keep the actuator to maintain the control panel start/stop and faults. Wonder how Overvolt And Overload would be handled, would lose these after inverter is removed.

 

[Demoh]

ooo I like the concept of where this is going. A quick search just on the base engine (the L70) is rated to 3600 rpm so I would think that pushing the engine to this would be fine, assuming the specific variant of L70 thats in the 831s dont have any changes that prohibit them from running at 3600rpm.

If I end up having an extra 831 where I am unable to revive the inverter I would be considering doing something like this. Problem is today alone added 3 or so "projects" to my plate just browsing the forums here so I might get to this in 20 years at this rate.

Out of curiosity because I searched a little but couldnt find an answer, Is the L70 that is in the 831 a standard bolt pattern like J609A or B, meaning direct bolt up?

 

[Light in the Dark]

One easy way is with my governor controller. I can easily change the firmware to make the 831 run at the correct RPM based on the frequency output of the new gen head instead of the frequency output of the PMA. Simple firmware change.

 

[profo]

The yanmar already has a governor internally set to hold at 3600 you just adjust the governor spring bolt you don't need the electric governor. See the post above about mep 831'sijverters. I have a few of these engines and made open frame generators using the northern gen 4500 it bolts direct onto side of engine all you do is then loosen then old plastic star nut on governor assembly push it down then adjust the 10mm head bolt tighten or loosening the spring screw to 3600 rpm or 60 hz at generator and it will hold it for you, when your ready to stop the motor you turn star nut CCW and motor will stop unless you want to go to eBay and get a injector pump with fuel shutoff soleniod then the mep controls can take over!

 

[Demoh]

... I have a few of these engines and made open frame generators using the northern gen 4500 it bolts direct onto side of engine ....

So for confirmation, the genhead with the J609B is the direct bolt up for the MEP831?

... all you do is then loosen then old plastic star nut on governor assembly push it down then adjust the 10mm head bolt tighten or loosening the spring screw to 3600 rpm or 60 hz at generator and it will hold it for you, when your ready to stop the motor you turn star nut CCW and motor will stop unless you want to go to eBay and get a injector pump with fuel shutoff soleniod then the mep controls can take over!

So I am following (by looking at a 831 right now) and the 10mm you are referring to is the one that is facing downward right?

For this to work I am assuming you remove the rod that goes to the electric actuator and the engine is pretty much self governing at that point? I tested this theory a bit and it seems to be accurate but wanted confirmation.

So theoretically we wouldnt need the generator controller at all unless we wanted some form of auto-shutdown feature like no fuel, low oil pressure, etc...

I am wondering the pros and cons to using the mechanical governor vs Kurt's controller with a custom firmware. Ideas? Im thinking maybe the electric actuator can be held in such a position where it doesnt interfere with the mechanical governor lever but when a fault happens it can shut the engine down. I would like to see this come to fruition.

Kurt, I know you have your hands full with the other project (Im in front of the gen this weekend so I should be re-packing when I get back into town) but I would be willing to provide you with a genhead to slap onto a 831 if you wanted to persue building this firmware and wanted a real life test instead of one with the inverter disconnected.

One thought. Need some form of power source for 24v and battery charging, that would be a con for the controller route that would have to be considered.

 

[Demoh]

So pondering the 24v battery charger, I havent done any probing around yet, but from the label the existing alternator has 40v @ 5A on the nameplate. So my thought process would be take the 240v from the replaced genhead and run that through a transformer to drop it down to 40v to feed the existing battery charger / 24v supply on the unit. A quick search on mouser I can find some "similar" voltage ranges, like I found 225va 234v to 36v, which is close (secondary rated at 6.25A) so I am curious on what A) the voltage fluctuation is for the output of the existing alternator and B) what the input tolerance is for the rectangular black box charger thing.

This forum is a bad influence on me. Way too many projects and it seems every other time I visit I find something else to add to the list.

 

[AfghanVeteran2010]

Keeping the existing charger seems like a bad idea, since it's a hard to find item. Might want to use maybe a battery tender, should run fine as long there is a battery on set. I don't think it would supply voltage with out a battery. Kinda wondering what the amperage draw is when set is on run position. Going to check that soon

Sent from my SM-G935P using Tapatalk

 

[kloppk]

Before we get too excited we need to verify if the 831's engine is a J609A, J609B or some other mounting pattern and shaft setup.

 

[AfghanVeteran2010]

This is the best info I could find so far.

I'm fairly certain the L70AE is a J609B, the PMA uses the J609B pattern.

Heres a spec sheet from Yanmar


Here's the J609B pattern, top offset is 30 degrees and the bottom is 45 degrees. The Yanmar spec sheet says (B-flange)

Here's the J609A pattern, definitely not this since it has a 3.63" bolt circle. The engine has another set of bolts on a 5-inch circle.


Picture from my set, with PMA plate attached.



Hopefully, this info helps out.

 

[kloppk]

Great info. I agree it's looking like a J609B bolt pattern.
Any chance you can measure the distance from the mounting surface on the engine to the beginning of the shaft taper and also from the mounting surface on the engine to the end of the shaft?
Also can you measure the bolt circle diameter of the bolts mounting the PMA adapter plate?

From your last pic it looks like the engine casting has the locations for the 3.63" bolt circle but they just weren't drilled and tapped as shown in the L70AE drawing.

From my looking on the web the J609B bolt circle diameter is 6.5"
Length of engine shaft to beginning of taper 2.5"
Overall length of shaft 4.45"

Looking at your last pic the output shaft appears longer than 4.5"

 

[AfghanVeteran2010]

Ya, I can measure it. Just have to pull it from set first. But before I do that does anyone have a pulled engine sitting around that they could measure?

Sent from my SM-G935P using Tapatalk

 

[profo]

So for confirmation, the genhead with the J609B is the direct bolt up for the MEP831?


So I am following (by looking at a 831 right now) and the 10mm you are referring to is the one that is facing downward right?

For this to work I am assuming you remove the rod that goes to the electric actuator and the engine is pretty much self governing at that point? I tested this theory a bit and it seems to be accurate but wanted confirmation.

So theoretically we wouldnt need the generator controller at all unless we wanted some form of auto-shutdown feature like no fuel, low oil pressure, etc...

I am wondering the pros and cons to using the mechanical governor vs Kurt's controller with a custom firmware. Ideas? Im thinking maybe the electric actuator can be held in such a position where it doesnt interfere with the mechanical governor lever but when a fault happens it can shut the engine down. I would like to see this come to fruition.

Kurt, I know you have your hands full with the other project (Im in front of the gen this weekend so I should be re-packing when I get back into town) but I would be willing to provide you with a genhead to slap onto a 831 if you wanted to persue building this firmware and wanted a real life test instead of one with the inverter disconnected.

One thought. Need some form of power source for 24v and battery charging, that would be a con for the controller route that would have to be considered.

Yes the bolt facing down is what you use to adjust the max trottle/governor and as for bsttery charger its mounted on left just hook up the 120 vac input to the new generator.

 

[kloppk]

... as for bsttery charger its mounted on left just hook up the 120 vac input to the new generator.

According to the TM the PMA provides 32-50 VAC to the Battery Charger.
Sending 120 VAC into it would probably let the magic "white smoke" out of it.

 

[kloppk]

...Kurt, I know you have your hands full with the other project (Im in front of the gen this weekend so I should be re-packing when I get back into town) but I would be willing to provide you with a genhead to slap onto a 831 if you wanted to persue building this firmware and wanted a real life test instead of one with the inverter disconnected.

I'd be game but before we go down that road we need to verify that the engine is J609B compatible.
Need someone to verify the bolt circle diameter on the 831 as well as the output shaft dimensions.