There have bewen a few threads about overheating generators so I thought that I would let you folks have a crack at mine. The genset is a Powertech CD7000 made in about 2000. I have only had trouble with mine while driving down the road. The exhaust ties into the main engine exhaust so I don't think that is the trouble. The hot air exits out the bottom. The air intake is about 10"-12" behind the exit. I suspect that the generator is sucking its own hot air in causing it to shut down. I have thought about ducting the exhaust air under the rig. I have also thought about moving the intake to the front of the bay. Maybe I sould do both. I will try to post some pics. The slot on the left is the exit (toward the front), on the right is the intake.
More pics
Don't have any input on yours, but the folks here will solve it or die trying. Mine is overheating also and I haven't had time to try some of their ideas.
Good luck.
glen
AndyG , I believe in you case a simple air dam (flap) will cure your problem make a dead space
good luck
Boy I hope you don't crunch that big ol muffler one day-I'd reposition that somewhere else or use a smaller muffler. Good Luck, TomC
would you put the air dam on a 30 degree angle or straight across? How far down 3-Inches?
With the exhaust tieing together is it possible that the main engine is creating to much pressure for the genset to be able to push its exhuast out? This will make it hot real fast.
The trucks exhuast is probably to much back pressure with the engine running for the genset.
I agree about the exhaust, that is a very strange setup to say the least.
An air dam will create low pressure at its rear, maybe, it is very difficult to predict results on the bottom of a bus with its many strange air currents.
^^ I believe its in a toter, not a bus, not that it will make much of a difference on air flow.
What is a toter? Is this a trailer?
It's a freightlinner chassis with living quarters also still having a 5Th wheel to pull his steam engine. Is my son Andy. referred to as a Totter-home. Bob
Ya I just said toter for short instead of toterhome.
I'd be tempted to try Clifford's suggestion. (as most of us know Clifford is seldom wrong, but has had many years to learn from also)
But I really think Eric is on the $ I didn't know until today that they are tied together or I'd thought this sooner! If it were me Andy first thing I'd do is rig a temp exhaust stack to run it up near the top rear of the "quarters" and see if it behaves any better. (I'd bet there is to much back pressure from the engine)
It also will get your exhaust fumes & noise up and away from the unit and make it more pleasant to sit around and hang out near the toter while waiting for dark to put on a "spark show"! (yes your dad's been talking and sharing pics & videos! LOL)
;D BK ;D
Sorry for asking a non-bus question here but this is where the knowledge is. I can't find any comparable site on toterhomes. The large muffler seen in the pictures is for the main engine 5" exhaust I think. The generator has the typical size muffer and ties into the large exhaust after the big muffler. I had not considered exhaust back pressure as a problem. I agree that it would be nice to route the generator exhaust through a vertical stack and may at some point. Installing a stack would be a pretty major modification so I will add it to the list. I would like to hear more about the airdam idea it sounds fairly simple to try.
Andy how is your genset exhaust tied into the trucks exhaust? Is it a Y or is it a T? If it was a Y (in the correct direction of coarse) the engines exhuast would help pull the exhuast out. But.. I guess it could actually pull it out to fast and cause a problem aswell.
I'm pretty sure that it is a T connection. I'll have to crawl under to check. About a 1" line feeding into a 5". Maybe I can take a picture under the coach. For reference, the generator is located in the center bay on the driver's side.
Since we are discussing this on the forum. I was behind you once when it quit. Were you shifting? At St. Joe& Diamond) If so could it be a exhaust pressure surge? Also it happened once on county road at lower speed 40mph , were you taking off?. Outside the box I know. Dad/Bob
Quote from: robertglines1 on September 19, 2011, 05:35:49 AM
Since we are discussing this on the forum. I was behind you once when it quit. Were you shifting? At St. Joe& Diamond) If so could it be a exhaust pressure surge? Also it happened once on county road at lower speed 40mph , were you taking off?. Outside the box I know. Dad/Bob
I was to busy hold my toungue just right to make the next gear change. I did not notice if the generator dieing was related to gear shifts or acceleration.
Oh!!
I knew that, being on a bus board threw me off!!
Andy, the generator tied to the truck exhaust is a common installation on toter's and truck type RV's I don't think that would be your problem as there is no back pressure on those exhaust systems
good luck
Thanks luvrbus. This is a store-bought conversion (NRC) but that does not mean that they got everything right.
What chassis do you have a friend has a NRC on a Mack and his generator is tied to the truck exhaust we installed a air dam on his and solved his shutdown problem,have old dad build you one 1 ft x 4 inches install in front of the generator fresh air intake installed on a angle
good luck
Clifford are you basically suggesting a air scoop? Any problems with water issues while driving if so?
I this case we are redirecting air currents and creating a minor vacuum
Quote from: luvrbus on September 19, 2011, 01:41:05 PM
What chassis do you have a friend has a NRC on a Mack and his generator is tied to the truck exhaust we installed a air dam on his and solved his shutdown problem,have old dad build you one 1 ft x 4 inches install in front of the generator fresh air intake installed on a angle
good luck
Thanks luvr.. The air dam is certainly easiest idea and worth a try. The hot weather is just about gone hear so will have to find out if it works next summer. My toter is on a 1989 FLD120 with a 350 BCIV (Cummins) and eaton 9sp. I forget the rear ratio but geared to run 70MPH @1700 RPM. The truck was a twin screw with 208" WB & 80,000GVW. The previous owner (PO) took out the front driver and stretched the frame before taking the truck to NRC. I can't complain about the conversion. Pretty soild work. There are a couple of things I would have done differently but nothing was done "wrong". This thing with the generator is minor and the days I had trouble were really hot and humid.
In trucks it has been determined long ago that tying the generator exhaust into the large main engine exhaust creates problems for the smaller engine. If the generator engine stops with one of its exhaust valves open, it lets exhaust and contamination into the engine. At one time Cummins OK'd tying an APU (auxiliary power unit) to their exhaust through the particulate trap. That is no longer accepted. I would always keep both the large engine and the generator engine separate on all accounts. Some have even tied the cooling system together to eliminate the generator radiator-fine if the big engine radiator is large enough-but usually is not the case since most cooling systems on buses are marginal at best. Besides-if one engine goes and it's tied to the other-it would most likely take the other out too (like coolant loss or oily exhaust caused by say a turbo failure. etc.). Good Luck, TomC
For the cooling air intake you want high pressure, not a vacumn!! An air dam in front of an opening does, indeed, cause low pressure (not sure it causes a vacumn though). A lowering of pressure decreases the flow of cooling air.
An air scoop behind a cooling inlet (to the rear of the direction of travel) should create higher pressure at the intake. However, on the bottom side of moving vehicles this is not guaranteed because of so many other things causing air currents to do weird things.
The only real way to find out is to experiment.