THE NEW "GENERATOR of DEATH"

On December 1, 2007, we received the new 20 KW 3 phase generator set, which replaced the old "Generator of Death", PU-708 US Marine surplus generator. The old unit developed a serious problem during the September VHF Contest. It ended up having to be shut down early Sunday evening with a destroyed air blower that wreaked havoc on the engine. A fix looked problematic, so we opted for a new machine instead. When the old generator had been rebuilt at a Marine Depot in 1976, someone had forgotten to put locking hardware on the two shaft nuts in the air blower. After we ran it for awhile, these nuts started to loosen, causing a slow loss of air pressure. The actual source of the problem was not detected and we started having engine overheating issues for a long time. The overheating started in 2004! this all culminated on Sunday morning of the 2007 September VHF contest, when the engine lost power and was belching black smoke from unburned fuel. We ran the engine on Sunday until about 8 PM when we were hearing clanking noises and shut it down. The engine was trashed at that point, as the blower had vibrated itself to pieces. The metal blower debris was blown into the cylinders. So it was time for a new power unit.

Shown below is the generator shed with the front removed so we can side the new machine into place on a recently poured cement pad. A friend provided a good sized tractor in case we needed some extra muscle to move the generator. Everyone is dressed for winter, as it was 14 degrees farenheit, with a wind blowing at up to 30 mph.

The generator appeared at 1 PM. We picked it up that morning, in Bangor, ME. about three hours away. Al, NS1O provided the Dodge RAM 2500 diesel 4 WD truck. It made short work of hauling the 1500 lb unit up the 4 wheel drive hill road to our contest site. Having a large 4 wheel drive vehicle made all the difference in this job. Here you can see it as it emerged out of the woods on the hilltop. (See below) The road is 4WD accessible only and winds about 1/2 mile through the woods from the main road.

We then backed the truck up to the generator shed and started rigging the planks and cement blocks to slide the 20 KW generator onto the pad, which is visible just behind Larry, K1CA, in side the shed. We really lucked out with the delivery, as it snowed heavily the following day and the hilltop became inaccessible, even with 4WD, due to heavy snow. The snow remained all winter. With a total snowfall of ten feet, it would have been impossible to haul the new generator up there until about Mid May of 2008!!

To get the 20 KW generator started on its way off the truck bed, we applied some heavy planking and cement blocks to support them. The next idea was to use a come along and a heavy nylon strap to persuade the generator to start moving off the truck. Once it started moving we needed all hands to staeady the unit and keep it centered on the planks.

Larry, K1CA lines up the cables in preparation of dragging the generator down the plank ramp and onto the cement pad. K1OR is helping Larry, K1CA hold the webbing while he hooks it all up. The interested bystander is Ed, my neighbor, who helped us with the manpower.

Once we got the big "Mamou" sliding, gravity helped it along and pretty soon it was sitting on it's pad and ready to be hooked up to the AC power buss. Visible in the photo, from left to right are: K1WHS, K1OR, NS1O, Ed Sardinha our next door neighbor, Jonathan Sauers my son in law, and Dana Beal, the guy with the big John Deere tractor.

Final adjustment required to get the 20 KW "Little G.O.D." centered on the concrete pad. A few metal pipes and pry bars worked wonders. The new genset has no switching capability, so we added a large 3 phase contactor on the wall of the shed, and hooked up the electrical connections with some short runs of #4 copper wire to the contactor. The output of that contactor is connected to the heavy cables that run to the ham shack about 100 ft away. The contactor is needed so that the shack remains disconnected until the generator is making full output at 60 Hz. Only then will it be connected to the main buss and circuit panel. After watching this new unit perform, we are inclined to give it a new name that indicates a more refined and docile machine than conveyed by "Generator of Death." This unit does not roar or belch smoke. It can't be heard 1/2 mile away. It does not seem like a beast at all. It just purrs along sitting there on its concrete pad. I ran it for awhile in the January contest, and with a 144 MHz 8877 amplifier, it seemed to work reaswonably well with a light AC load. The voltage regulation was good, and it also provided ample electric heat to warm the shack!

These generators are built by Central Maine Diesel, in Bangor Maine.They have various options available and many sizes from 15 KW up to about 100 KW. This particular unit has an electronic speed governor module on a 2.3 liter Cummins diesel engine for precise engine speed control. In addition, there is a solid state voltage regulation module on the Marelli 20 KW 3 phase generator end to hold the voltage constant under load. A third module acts as a controller for all of the engine functions and protective circuits. It senses oil pressure and water temperature and provides emergency shutdown in case of high temperature or low oil pressure. In addition, it will sense a high engine speed, overcranking at startup. It even provides an automated start sequence for glow plug heating and engine start. We are "stylin'" for sure. Now all we need is a good AC ammeter panel to check power loading for each phase. I obtained some AC current transformers and will rig something up on the wall to monitor the current on each AC leg. When that is all done, we can get back to working on improving the ham station! We have decided that having good reliable AC power is the most important facet of running a good contest station. Without it, as we were in September of 2007, and you have nothing.

So the first big test for the Central Maine Diesel generator was the June ARRL VHF contest. It failed miserably! No sooner had we started it and started to load up the transmitters when it just shut down with an overheating engine failure. From June 14th to July 10th, I had to fight with Central Maine Diesel to even honor their "labor" warranty. A representative of Central Maine Diesel informed me that there was no labor warranty. After some verbal confrontations, they finally agreed to come and look at their malfunctioning engine. The repair tech who came on July 10th noted that it overheated in five minutes with a 19 KW load on the generator windings. This was not good. A further inspection revealed that someone had never put a thermostat in it, or someone had removed the one that was there. Of course he did not bring a thermostat along on an overheating repair call. (?) I agreed to install a new thermostat to save them a trip. The new part arrived from CMD on July 17 and of course it was the wrong part. I am now of the opinion that Central Maine Diesel is a not so competent dealer in generator sets. I would never ever consider buying anything from them again. So far this Summer I have missed the June VHF Contest, and the CQ Worldwide VHF Contest. I guess I'll be missing a few more at the rate they are going. Just getting reliable AC power is turning out to be difficult as long as Central Maine Diesel Power Systems is involved in the process.