Powertech Generator/Kubota overheating

[GregOConnor]

It may work to add a screen to the inlet side of the fan cage. maybe a filter is too much as it would probably be ok to let dust just blow past the radiator. The design issue is that the collection point for sucked up debris is the flat horizontal radiator face. once the fan is turned off ,there is no gravity acting to pull the surface clean like it does with a upright car radiator. A screen to the inlet side of the cage fan would stand vertical and debris would drop once the fan stops sucking air in that side. if you only let dust in to the fan cage or particles as small as the radiator fins can pass, you can then just wash out the radiator with a hose. the screen would need to be removable to flush wash the radiator fins.
While in that radiator compartment I removed my AT relay and replaced it with a 80 amp breaker marine switch. the A.T. relay stays hot and sucks up major amps (phantom draw). there are a couple of other electrical items close to the frame of the bay door that I also replaced and updated with marine grade relay/switches. I had a electrical ground short in that area when vibration caused the frame of the bay door to contact a 100 amp lug. (the stray voltage also forced a fault light on the allison display but no code when I hit freeway bumps for months)
The debris you cleaned out was most likely the cause of lugging of the old motor because the motors effort was hitting a solid wall and could not push the air it collected. the opposite of plugging up a vacuum hose. But it doesn't hurt to replace a 20 year old vital component. damaged motor was a result not a cause.

[davidbrady]

Great idea Greg,
Here's what Vantare uses on the louvered compartment door that feeds air to 2 cruiseairs and the generator radiator:

[GregOConnor]

That is a good way to move air out of that compartment also. the 94 wide body genset radiator bay is open air. There is a baffle under the radiator that directs air out to the curb. I can see that without the baffle it would just be recirculating the air as the used air rose to reenter the compartment. Kind of a bad design but with the overkill fan it works. I dropped my 230v ac fan and installed a 12 volt automotive set up. I used the hour meter signal to open the fan relay because the hour meter is delayed start for 20 seconds while the genset is starting. I didnt want the 12 volt fan to tax the amps when I tried to start the genset. I later installed a two speed thermostat for the fan which also works to keep it off when starting the genset.
here is an image of the electrical issue in the comparment. the circuit breaker by the door sill (right hand) is raised on a stock of extruded alumnium to give access to a reset button under the breaker. the wire running to the a-t relay made contact and cooked the insulation then burnt up the a-t relay dropping the contact out of the bottom. I was by chance on the other side of the bus and immediately dropped both battery shut off switches and the genset. I smelled the electrical and thought it was the gen set. but it was the insulation and plastic from the relay.

[Arcticdude]

Wouldn't you be better off putting a screen on the inside of the genny control bay (between the genny and coach chassis)? Just running down the road would get stuff to drop off the screen and be self cleaning. Probably a lot more work to install, but it may work better in the long run.

[davidbrady]

For the case of my Vantare, the louvered door is an air inlet. It's easy to stuff a cheap fiberglass filter between the louvers such as these sold at McMaster Carr. The air is then expelled thru exhaust vents in the basement floor. You can see that the bristled skirting along the sides of the bus also come into play preventing air recirculation. As we all know, these fiberglass filters become quite efficient as they build a static charge. Even fine dust can be caught which is important for my cruiseair condensers.