Changfa 1115, 12 kW 3-phase genset

[rcavictim]

A few years back I was able to purchase a new Changfa 1115 engine from Pat at Altopro.  It has the electric start option.  I have been waiting all this time to come upon a suitable 3-phase 480 volt gen head so I could put together a plant that would become prime/backup to my existing shop workhorse, my DIY 1.5 liter VW Rabbit engine based 9 kW 3-phase 480 volt plant.  I use the VW genset regularly to power my machine shop and the house on occasions when there is a power outage.  Once I am off grid I will absolutely need a similar capability machine as a backup to the VW.

I finally found the gen head I wanted to use and purchased two of them from Tom Osborne.  The plan is to put the second unit on my wind turbine which is slowly approaching completion.  I went with the STC, 24 kW (30 kVA) 12 wire 480 volt 3-phase head.  These have a built in AVR that works off the harmonic winding but can also be run from the output power winding through a xfmer if needed.  The waveform on these is really clean without the distortion hump seen from the harmonically excited single phase ST heads.

Being as the Changfa's and any other single cylinder diesel other than a slow Lister are rather noisy, I need to put this plant in a room within my shop where the door can be closed and noise controlled.  I have such a room now where my noisy Petter PJ-1 air cooled 803 cc, 5 kW single phase plant lives.  In order to also fit this new genset in there where floor space is at a premium I had no option but to stack the gen head above the engine on this machine to minimize footprint.  No option for direct drive therefore so I had to go with a belt system.  I managed to obtain a pair of 9" OD shieves that handle 4 and 6 B size belts and put the four belt on the STC head.  The 6 belt went onto the engine by way of a DIY keyed shaft which I made up here on my lathe.  A common back 4B belt connects the two and a tensioner idler is included in the path on the slack side.

I include a picture taken before the guard was fabricated to show the belt path.

The base is really heavy being 3/8" thick box tubing all sand filled.  The four vertical 4" box tubes are also sand filled.  Castor wheels are solid metal.  I discovered one of the factory cast iron engine mount brackets that came with the Changfa had already broken open in two places while I had the engine on a temporary lashup bolted to a pair of heavy I-beams. I'd heard that this is a weak part and that they can break.  It is true! That made the decision easy to make my own fracture proof mounting out of 1/2" thick mild steel.  There is no rubber floating isolation between the engine and frame or the gen head and frame.  I do have rubber isolation to the 10 IMP gallon fuel tank (a repurposed and modified watersystem bladder tank) and the radiator/blower package. I also plan to shock mount the starting battery, bracket not yet made.

I made a larger volume expansion tank for the exhaust out of a portable air pig sold by Canadian Tire for filling tires (dump score).  The final silencer is a commercial unit I purchased many years ago new which was very expensive.  I just tore into it and removed half the guts and spark arrestor, replacing the second half of the flow path with basically a large core glasspack muffler.  It makes the exhaust quiet enough I can now run the plant at night without bothering the neighbors.  I punched a hole through my shop roll-up door so I can test run the plant where it presently sits.  It is not shown in it's final generator room setting.

I have the plant operational now and can actually use it although I still have some details to finish including some instrumentation and a proper electrical box.  I have run it with an 11 kW load at 1800 RPM and there is no color yet to the exhaust.  This is an impressive engine!

[rcavictim]

More pics...

[mobile_bob]

very nicely done!

i like it, it turned out to be a nice compact package.

good work.

bob g

[rcavictim]

very nicely done!

i like it, it turned out to be a nice compact package.

good work.

bob g

Thanx Bob!  It can fit through a 27" doorway and is fork friendly between the wheels so can be lifted with a big enough forklift.  It has to weigh close to 2000 lbs though. A smooth concrete floor is my friend.  Pretty much theft proof.

[rcavictim]

VERY nice !!!!
The belt looks like it doesn't have any ribs on it - optical illusion ?
Could you post a picture showing idler details ? How do you tension the belt ?
Nice welding job on the shaft to engine adapter !

The whole thing looks like it might be difficult to service with it being as compact as it is.

That is an optical delision.  A nudder picture when I first tried the belt in my temporary lashup shows the belt ribs better.

I measured the placement of everything very carefully then ordered the belt.  I bought a common size to make getting a replacement which I ought not ever need, easy.  These are expensive suckers.  The idler has no adjustment.  It has to be removed to swap the belt, then reinstalled. To fine tune the belt tension I have a set of washers under the engine mounts.  I can drop the engine 3/32" as it is now on one set of washers should the time come when tension needs to be increased.  Alternately I could add washers under the gen head.

The idler is a solid block of aluminum turned on the lathe to accept a sealed ball bearing into each end, interference press fit. The bearings have a 3/4" bore and are on a grade five allen head smooth shank bolt. The pulley is raised only on each end and is smooth along the valley where the ID of the belt rides.  Too much unnecessary trouble to try to duplicate a four groove shieve.  If it was the least bit incorrect it would have caused shortened belt life.  I'll try to get a closeup picture for you.

I actually designed it with easy access to the engine for rebuild right in place.  Thanx for the compliments.

[rcavictim]

Here are pictures of the fuel tank under construction and an image that conveys well what a great invention paint is!  What would I do without my trusty heat gun?!  This water system tank was like brand new and it followed me home from the dump years ago.  It is amazing how one can save a bundle making things you need out of other things other folks don't need.  The disgarded 20 pound and larger propane cylinders also make excellent fuel tanks and silencer/muffler casings.

[rcavictim]

I mentioned above how the output sinewave from the 3-phase STC heads is free from the nasty distortion that is present on single phase ST heads that also employ harmonic winding excitation source.  The attached scope photo shows the nice clean sinewave on one of the phases with an 8 kW load on the 24 kW STC head.

Given that one has so many connection and output options with a 12 wire STC head that include 120-0-120 VAC single phase, and that they are now available for a good price with a built in AVR module that appears to work well, I think the choice to buy a STC for a single phase application would be wise.  There are then options for down the road that you otherwise wouldn't have which make it a nice bonus.

[veggie]

Very nice job !
That's a monster Changfa setup !
I can't wait to see the video. Any chance of posting one on youtube ?

Pleeeaaassssse ! 


veggie

[rcavictim]

Very nice job !
That's a monster Changfa setup !
I can't wait to see the video. Any chance of posting one on youtube ?

Pleeeaaassssse ! 


veggie

I've not yet learned how to post videos to youtube and the quality of what I can make is poor with my present digital camera.  I would be happy to email you the best of what I do have if you send me your email address via email.  It would be a 4 or more megabyte sized file attachment.

[WGB]

Nice job RCA!
I would like to see a video also.
Thanks