Micro CoGen.

I found a 60uf cap and now I am in business, thanks for the input.

The largest load on the unit is my pool pump. I supplement my electric usage with a generator transfer panel. I swap my 120 vac load in the house and shop. I also run a 500 watt attic fan to remove the heat from the attic which reduces my AC load. So the pool pump, attic fan and lighting, TV's, pc's and ceiling fans are the load and it is about 2800 watts or 111 volts x 11.7 amps on one leg and 112 volts x 11.3 amps on the other. Do the math and that is 1299 watts on one and 1266 on the other plus 1/2 an amp for cooling fans on the genset. So that's less than I said at 2600 +/- watts. My Fluke 287 on the terminals of the disconnect indicates 60hz and the corresponding voltage per leg. It doesn't really decay much as the genset temp goes up like the ST head did. Just my luck I guess. I will put the water heater on it tomorrow by itself with is 4500 watts of resistive load and report back. Increasing the capacitance value would mean going from 45uf to 50uf or the other way around, 45uf to 40uf?

Ok the 40uf cap went the wrong way with the voltage so tomorrow I will get a 50uf. I guess I read your post wrong Bob, my bad.

Quote from: mobile_bob on April 13, 2015, 10:48:16 PM

if that does not help then increase the capacitance value as stated, but work to keep the unloaded voltage around 126vac or so to be safe.

bob g

I verify the freq and voltage with a digital fluke meter and at 60hz no load I get @ 116 volts per leg. I bought an american made motor run cap yesterday at my local HVAC shop and nothing improved. I will head back over there today and get a 40uf cap and give it a try. Also at 62hz I get @ 124 volts per leg no load but when loaded with about 3kw it droops to 110 volts per leg and even lower when more load it placed on the genset. Thank you guys for the input it is much appreciated.

Ok my ST head would not develop voltage any more, I purchased the Harbor Freight gen head with the 20% coupon online and it was shipped to the house for 275.00. The fan melted the first run so I took that off and also replaced the flimsy plug/gauge panel with a 12x12 carlon pvc box and mount two 4 inch fans forcing air thru the gen head, so far so good. The only concern is that it will not maintain 120 VAC or 240 VAC when loaded @ 3000 watts. It drops to around 110 or 220, I don't think it will hold if I loaded it more. It has a plastic capacitor 45uF 450volt, would a higher quality and/or different value make a difference in output voltage. So far this is the only issue I have with it. It is much quieter and has less vibration than the ST head. It runs hotter than the ST but that is to be expected with it's compact design. I hope someone can advise me on the capacitor as I really don't understand how this brushless unit works . I had a 5500 watt portable unit once that would maintain 240 vac with our electric water heater appling the load. Thanks for looking and have a good day.

I looked into net metering here in florida and in order to comply, your system be accepted and approved it has to be installed by a licensed contractor (absolute BS in my opinion). There is a minimum size for the solar array and multiple other restrictions. I work for a large utility and perform work on electrical systems from 120 VAC to 4160 3 phase. I have no issue wiring the system to code but it must be done by a contractor before the utility company will buy into it. All the red tape involved makes this a real headache and paying a contractor 3 to 5 times what the system really would cost just isn't worth it at this time. Once the price of solar starts coming down it may be worth it and then I can run my little yanny on waste ATF and earn credits with the power company to offset the summer power bills. Why does everything have to be so damn difficult!!!!!

Hello, I currently producing some of my electricity with my yanmar/st genset thru a generator transfer panel. I am interested in solar grid tie and well as running my genset in grid tie as I currently run it with used ATF. I need to understand how to tie this to the grid with an invertor that will accept a DC input from PV panels and a 240 AC input from my genset. My genset is not big enough to run the whole house but with grid tie it would cut my consumtion quite a bit. What type of inverter would I need? I understand that I would also need a auto disconnect if the grid goes down as not to back feed the grid. I could also use an alternator setup for DC power generation but that is a cat of another color and not really and option because I currently produce AC power. Would I need a net power meter from my local power company? What regulates the output of the genset say a constant 5000 watts, the inverter size? Any help and guidance would be appreciated.

Regards Dave

Quick question about exhaust temp limits for these little engines. I used an infrared temp gun to check my exhaust temp while at different loads. At the highest load about 4500 watts the exhaust pipe metal temp right at the flange where it bolts up was 600 degrees F. With about 1000 watts it read 360 +/- degrees F. Also the oil pan metal temp was indicating the lube oil was running @ 200 degrees F at 4500 watts and about 190 degrees F at the lower load with oil pressure indicating a tick below 60 psi. I am running the Rotela 5w-40 synthetic oil. Do these temps seem to be within normal operating range???

Sweet, thanks for the replies. I actually had a neighbor complain yesterday about the noise. I moved the intake filter box outside the metal building over the weekend to allow cooler air to enter the engine. The neighbor came over and asked is that a generator you have running?? I said yes and asked him how long it had been bothering him and he said only a few days. I thought thats funny because it has been in service for more than a year. Now the intake is outside it echos over to the street behind me. Thanks pressurepro I will be looking for those part numbers and if those ar too expensive I will try to find a used air intake system from an old GM diesel pickup.

Maybe something like this!!! http://www.ebay.com/itm/YANMAR-AIR-CLEANER-ASSEMBLY-PART-129030-12501-NIB-GENUINE-PART-SEE-DETAILS-/350609500017?pt=BI_Heavy_Equipment_Parts&hash=item51a1f46771#ht_337wt_896

I have my genset rigged with an air box from the same car I got the radiator/fan/over flow can. The intake air seems to be pulsing at the inlet of the filter box. This is also creating a droning sound that is louder than the exhaust. Do I need to run one of those round canister style intake filters found on heavy equipment to suppress this sound. I can hear it in the house over the exhaust or even the natural noise the engine makes. I read that the small 2 and 3 cylinder diesel have this pulsing intake but cannot find anything about how to suppress it. The other day we had a small track hoe onsite and it had a 3 cylinder yanmar for power and it was quite as a mouse even with the engine compartment door open. I need help as this is driving me crazy. 

Thanks for the reply. I see it took six hours to raise the 500 gallon tank 40 degress to 162 with a 40 plate heat exchanger. Right now I am only trying to heat a 50 gallon domestic tank. I run mine about 4 hours a day in the evening so a 40 plate heat exchanger might be to larger. I am afraid I might have to add a bypass around the exchanger because my tank will rise to max temp longer before my 4 hour run is over. If I use you formula, I would need 6225 btu/hr to raise 50 gallons from 100 degrees to 160. I need to look at a data sheet for the heat exchagers to find the right size. Thanks again, Dave

Tom, I understand your idea but I have only a standard AO Smith hot water heater. So in order to keep my cost down I was going to run my domestic on one side of the plate exchanger and engine coolant on the other for now. When it is time to replace the exsisting HWH I will buy one with the coil inside as you mentioned. I think someone said there would be an issue with running domestic along side engine coolant but wouldn't the water pressure on the domestic side be higher than the coolant side? If a leak in the exchanger where to happen the domestic would bleed over to the coolant side. The domestic is about 70 +/- psi from the city. I have found a heat exchanger and a circ pump so now I need to purchase those plus the pex and get to work. Thanks to everyone who responded as that is where alot of good info and FYI stuff comes from. I always learn something new when I come in and look around. Thanks again.

Thanks for the reply. I checked and the pex/taco pump looks like it is rated for 200 degrees F @ 80 psi. Now the next question is how many plate exchanger to buy. I was thinking a 20 or 30 would do it by looking at the data sheet for each. I may have to install a bypass valve if the domestic water reaches its maximum temp and just throttle or bypass coolant around the exchanger but this will be a manual operation. Also the engine with @ 1500 watts on it holds pretty steady at 180 degrees F out of the engine. This does vary with ambient temp. It runs as high as 210 with a 4000+ watt load on it. Again thanks for the reply.

Are you running the engine at 3600 rpm? I have mine set to 2800 +/- and a 7.5 kw ST head for 1800 rpm. I can only produce about 4500 watts at that engine speed. I know it makes more horse power at 3600 rpm but wanted longevity from the engine. Could you show a picture of your plate heat exchanger as I want to heat my domestic hot water off the coolant side of the engine. I live in florida so the heating load here isn't much so there is really no need for capturing all the btu's the engine puts out. I built mine as a back up for outages but since found a steady supply of used ATF. I filter it and mix it 90/10 with diesel fuel and supplement my grid power in the evenings when at home. I run it for 4 to 5 hours a night and 20 gallons of the mixed fuel last more than a month. I posted a write up and pictures in the memebers project section. Here is the link:

http://www.microcogen.info/index.php?topic=3085.0

I am looking at heating my domestic hot water with my yanmar 2tnv genset. I am curerently running it about 4 to 5 hours a night to supplement my electric consuption from the grid. I am burning a 90/10 used/filter ATF to diesel fuel mixture. I thought I might as well heat a tank of water while running the genset and adding a tempering valve for the hot supply to the house. I think I want to use a plate heat exchanger like the ones on ebay or from Duda Diesel. The ones Duda Diesel sell have a 3/4" max sized inlet and outlet. This is a concern as the coolant hose from the engine to the radiator is about 1.125". I was going to route the hot coolant thru the heat exchanger and then the radiator. Will this 3/4" port restrict to much flow for proper engine cooling??? My hot water heater is located in the garage and is approx. 50 feet from the shed where the genset is housed. Would this pose a problem using pex pipe and a circulator pump or will that be ok. I just hate to put the money out on this project and get an unsatisfactory result. Thanks for any tips and tricks I know you fellers have up your sleeves.