I have an enclosed 8KW Kubota 3cylinder powered generator running heaters to take the chill off my sea can through winter. I'm finding it doesn't hold hear or even get warm. Points to add at this point. The cooling fan currently pulls air through the gen set and out through the rad housing. There are vent holes in both side doors and the front door and radiator end. I'm yet to cover the side doors but figure since it's pulling unrestricted cold air through its not going to make much of a difference. I know fans are designed to run in a specific direction, but is it as simple as turning it around to reverse the air flow, making a winter front more effective at restricting air flow through the rad. I'd also do the same for my Miller trailblazer... It too doesn't get warm
No, it will still push or pull the same direction because the engine is turning the same direction. It will be less efficient installed the wrong way, significantly less efficient if you're overheating, not enough if it won't warm up in the cold. Is this gen inside the can, or outside? I can think of all sorts of changes you could make to get more heat inside, but easiest would be to put the generator inside with an exhaust going outside.
How bout replacing the thermostat?
This is one of those things that seem to come up every so often and it always gets me that so many people don't have a grasp on why it will not work. I always try to explain that a fan blade is nothing more than a very short piece of threaded rod. Anyone see why many boat people refer to the propeller(another version of a fan)as the screw? Picture clamping a nut in a vice and take a section of threaded rod turn it clock wise and it will thread into the nut(assuming it and the nut have right hand threads). Now take the piece of threaded rod and turn end for end and guess what turning it clockwise it still will thread in to that nut! Now with most fans the blades are designed in a way that they are more efficient when facing the right way but even if installed backwards they will still move the air in the same direction but with a bit less efficiency!
Figure out a way to enclose (a shroud) the exhaust system to preheat the cooling air ?
Put a piece of card board fronta the radiator...
Am I missing something, I took it as he was concerned about NOT retaining heat.
None likes a scabby piece of card in the rad... I'll start by insulating and filling the door vents and getting a partial cover for the radiator. Would have been nice to change the direction of airflow but no big deal
Keep in mind that the air flow is designed that way to keep the generator section cool, if you put a suction fan on you will be putting hot air on the generator.
Agree, and I might not be really understanding the problem. Is there a problem with the cooling system of this engine like a bad thermostat? Or are we talking of a application in sub-zero temps for long periods of time. Or is the load on the unit way too low? Not sure what the minimum load that a genset like this should be working under. Years ago we had a 3-53 Detroit genset that they used to just run a block heater in a 3412 Cat genset overnight and weekends and a few lights. Anyone who knows Detroit's can imagine the wet stacking that caused.
What is the kVa rating of the generator and approximately how much load do you have on it.?
Problem is the unit doesn't hold heat. Ambient air temp through winter will average minus 20. Much colder at times but not always. The unit is 8Kw. It runs two electric heaters at 4800w each (peak) and x4 60 watt incandescent bulbs. My thoughts would be it is under close to full load consistently. Seen these things fail due to lack of load before. The cooling system does not have a problem. I don't like that the unit doesn't get warm... Efficient running should be at running temp not at warm up temp.
Noted. That would be my only real concern in reversing the fan. Not sure if it would have an adverse effect on the generator. But with the cold ambient temperature would it make a difference?
Seems like you have plenty of load on the set so that's one box ticked. The problem is that you can't just "reverse the fan" unless you can find a "left-hand threaded" (puller versus pusher) fan spider for this particular application. See KSH's post #4 above. Thinking about it you could reverse the air flow direction IF you could turn the fan round as per your OP, but THEN you would need to also reverse its direction of rotation as well. I would imagine that's not practical. Here's a thought. If the engine is staying so cold why not try removing the fan completely just for a test and see what temperature it runs at..? It may be that your ambient is so cold that radiated heat would be sufficient to keep the set at an acceptable operating temperature.
I'm tooled up with some plywood to block off the door vents as a test. Will post the results
You can definitely find the opposite direction fan for that engine. You just have to find the part number off a puller fan the same size that went in a piece of equipment with that same engine. I have seen a lot of those engines for sale on ebay as a puller so maybe borrow the serial number off one of them. That being said, if it was me I would never ever restrict the air flow so bad that if it got warm the engine could not cool. Overheating is far worse than running cool I am sure you know. I assume this unit stays cool because the block is losing all its heat to the air flow. I wonder if you might remove the radiator air flow from the equation entirely somehow. Or wrap the block with insulation or something. Don't allow the generator head to overheat whatever you do.
I agree there should be a reverse fan available. I have one for my skid steer with a Kubota but don't use it anymore. While it helps keep the cab warmer, if the entire machine isn't spotlessly clean it stinks up the cab from even slightest bit of oil or dirt in the belly pan. For more heat I'd see if a higher thermostat is available. I run a 190 in my tractor with a Perkins and never have any problems in the hot summer. Another thought is put a small electric heater with a thermostat in or around the engine on the generator.
Okay how about this idea? Can you locate a set of shutters off an old over the road truck? Not sure if anyone uses them nowadays. Of course that would require a source of air to actuate them with a shutterstat mounted on the engine. Maybe a small electric air compressor?
I used to have a welder with manually adjusted rad shutters. It was part of an Arctic modification.
Hhhow about removing the fan and install thermostatically controlled electric one in front of the radiator. They are readily available. It could be mounted to push or pull the air.
An electric fan sounds like a good idea. Could possibly use one with less CFM than the original fan to let the engine be a little warmer.
I am normally against electric fans but this sounds like a good place for one.
Millions of cars have them. Keep in mind they can turn on at any given time. So keep your body parts away from it unless the power to it is off.
Millions of cars have them but they rarely run. And are not usually asked to get rid of the whole heat load of the motor, more for idling. A generator set does not have the benefit of ram air at any time.
Very true Birken Vogt. I think they were designed to increase fuel economy. Like the conventional water pump pulley mounted fans with clutches that came into use many years ago. I thought in your situation that an electric fan would be a good option. No air flow through the radiator until a temperature rise would turn on the fan when cooling was needed.
Also better take stock of what size alternator that unit has on it and what any proposed electric fan draws. A lot of tiny Kubota engines have an equally tiny alternator and the fan might draw more than it can take, not a 120 amp unit like a car.
There's 8Kw of electric to tap. Lose the incandescent light bulbs, replace with LED. Now you have a 200 watts to run a fan. Though it might not be enough during the Summer. Does the generator have its own fan ?
I have to make a correction / comment on my last post. I meant to say --- I thought in simonrsplant's situation that an electric fan would be a good choice.
Remember we are talking about a genset here. Needs to be bone simple and 100% reliable. Operate unattended for weeks of run time with no down time. Any electric fan that is a one-off 120 or 240 volt or even 12 volts from a car is suspect. It is hard to get custom stuff reliable. I've seen it dozens of times.
Yeah a generator will have it's own cooling fan, but you have to get the heat out of the enclosure after the generator fan kicks it out. Birken is right, you want stone simple and a mechanical fan is. I think a thermostat change is in order before reinventing the fan system on the gen-set. I'm guessing the incandescent bulbs are also giving him some aux heat also, so no real issue here.
I am guessing that the thermostat is never opening and the engine block is acting as an unregulated radiator here though.
Then an insulating blanket on the block or diverting the air from the radiator around the block (and to the generator) is in order.
OK, then how about a viscous fan clutch? No external plumbing/wiring or controls. Or how about contacting the genset manufacturer to see if they have recommendations for extreme cold weather applications? Or what about Kubota, maybe they would have some information related to cold climate applications of that engine?
If you wanted a reverse, buy another fan. I picked up a reverse fan for my JD 350 dozer, it keeps the floorboards defrosted when running it in the winter time, had issues with ice and snow getting packed around the pedals and stuff when using it as a snowplow. I picked mine up from Jegs, they have quite the assortment.
I'm going on the assumption that this genset is not running unattended for long periods of time, say a week or more? If the outside temp does raise to a point the reverse flow of the fan could cause a problem with reduced cooling capacity the need for heat in shop would also be reduced thereby taking some of the load off the engine. Also as I'd be guessing the stock cooling system is probably designed for temps in the 35-38ºC range if the temps do get up to 10-15ºC there would still be, even with a reduction in cooling capacity from the reversed fan, still a bit of a margin of safety considering the heaters would not be putting as much load on the genset. I would suggest having the heaters in shop set at two different temperatures a few degrees apart. That way if one heater can carry the heating load by itself the second one would not be called on to add heat and thereby load on the genset.
I have seen a very few generators with a viscous fan clutch but have no idea how it is supposed to work since they are all pusher fans. I think they mount it real close to the radiator but it is a manufacturer known for their weird ideas so I would not put too much stock in it. One way to do it would be to put a puller fan with a viscous clutch and then duct the air inlet for the cooling of the generator itself to outside air so the generator head does not have to run in hot air if it gets warm outside. But a viscous fan in my experience still moves a lot of air even when in "neutral" so it might not solve the problem at all.
One way to warm up a sea can without a lot of condensation is one of the diesel fired salamander heaters, you'll need to open the door after a bit to keep the air circulating but they work great when they're tuned up properly so they don't smoke, running on kerosene helps too but less btu of course. Once its all toasty maybe your electric heaters would keep the pace. I've used one as a winter spray booth, pre heat to 110f let everything stabilize, shoot the paint, air it out then fire up the heaters to keep it above 100f for an hour. Its a bit overkill on the insulated containers.
Update: I used some canvas to partially cover the rad cover and the side vents. Seems to be staying notably warmer... However In the last few days the ambient temp has risen above freezing. I'll keep an eye on things this coming week.
Sorry for the late comments here .... I tried a few things with varying success. Final deal was pretty straightforward. I had some covers made up at my local custom tarp shop to clip on the inside of the side doors. It seems to keep the unit considerably warmer. Not yet had a very cold spell but I'm confident it will work well for what I'm looking for. The appearance of the machine is factory aside a few rivits as the covers fit internally.
you could just make that cover like a weather front for a truck, with two zippers down the middle.
Used to be things called shutterstats on the off highway trucks around here. I wonder if temperature controlled shutters are still made today? They seemed pretty simple.