Rebuild of the DADI/ChangChai generator system to eliminate problems

The DADI Generator itself was of poor quality,  15% harmonic distortion,  fluorescent light flickered when the system was operating,  generator would not reliably start generating electricity unless the stator was "flashed" with DC after the engine was started,  engine connection bushings wore completely out in 45 hours due to alignment problems,  the meters failed,  the circuit breaker failed,  and overall it was just unreliable.  The radiator on the ChangChai engine was shaking so that metal fatigue was tearing the housing and shroud.  If you accidentally forgot to shut off the ignition switch after you shut down the diesel engine,  the battery would be run down because the alternator remained connected.   Something had to be done to improve reliability and operability.

Can we make a silk purse from a sow's ear?
Well..  We gave it a try,  here is what we had to do.  (Note: Right Click picture to see full size photo.)

I bought a new MECC ALTE alternator from Hardy Diesel.

New Generator "almost" fit but required new flywheel        New generator connected to engine and mounted on
and flywheel housing.  Notice that the new generator          new engine/alternator frame assembly.
has a laminated plate coupling system and bolts direct
to the engine flywheel.  No rubber bushings to wear.
The new generator has only one bearing and relies on
the engine rear main bearing to support the front of the gen.

Radiator disconnected from engine and mounted to the frame         Engine/gen from left side showing added
base.  Engine is now on rubber vibration isolators.                          solenoid to pull engine shutdown lever.

Left side view showing LOW voltage junction box on         Replacement control panel has 120vac meters and
top of alternator.  This has start relay, pre heat relay,          ammeters for L1 and L2 plus an accurate frequency
and relay which pulls in when MECC alternator output       meter, 12vdc meter and ammeter for battery,  plus
is more than 200 volts.  This relay connects DC                 engine temperature and oil pressure.  Toggle switch
system only when engine is running  to avoid running           to right of key is UP for preheat and DOWN for
down battery if ignition key is left in ON position                engine STOP. Max continuous output is 240vac at
when system is shut down.                                                 66 amps.

How is it all working?  Well,  so far,  so good.  The MECC alternator is FAR superior to the DADI alternator.  On startup of my home,  both ammeters "peg out" above 75 amps for a second or so as motors start and the voltage on the meters never goes below 117 volts.    I had one additional engine problem after running it for just an hour after reassembly,  I noticed the head gasket leaking and had to remove the head,  have it ground and replace the head gasket.  MAYBE it will be OK now.  But do I think that DADI and ChangChai make reliable equipment.  NO!  Would I buy another  DADI generator or ChangChai engine for any purpose?  NO!   Neither DADI nor ChangChai responded to any query or supported any of the necessary repairs and rework despite requests.  Thanks to purchasing the system initially using my American Express Card,  AMEX did purchase the new alternator unit for me,  but obviously lots of work was necessary to change it out and get it all rebuilt.

Small update:  The Starter Motor failure at 70 hours turned out to be another workmanship/quality problem.  The bushing plate behind the starter bendix gear is held into a recess with two screws.  Both screws had backed out.  One screw had backed out entirely  and had been completely ground up into bits of steel.   The other was only in by a few threads and was grinding on the front of the armature windings.  The screws,  as they were backing out had chewed up the armature wires sticking out of the front end of the armature.  One drop of Locktite on each screw or perhaps even a couple of lockwashers (there were none) would have eliminated the cause of still another expensive and time consuming failure of the Chang Chai Diesel Engine.

Joe Mehaffey

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