This is a picture of the 12volt air compressor I did not have a chance to get my out so I thought you could use this picture. The problem with most compressors is heat. I was told that the Oasis compressor has to be in the open or it will overheat.
12V / On Board Air System
- Thread starter Mamrak76
- Start date
Would you be interested in selling it to me?This is a picture of the 12volt air compressor I did not have a chance to get my out so I thought you could use this picture. The problem with most compressors is heat. I was told that the Oasis compressor has to be in the open or it will overheat.
Ok, I have more done. Wiring and such. Hopefully will have it installed soon. Does anyone have recommendations on using a 4in vs a 6 inch pulley on the motor?
1800 rpm motor.
4 or 6 inch pulleys that I bought
Compressor is 12.5 inches on the pulley.
what effect would making the switch to a 6 inch pulley on the motor? Rpm wise I can use either and still be within spec on the pump. What will change?
also did get my Nathan K5LA today
1800 rpm motor.
4 or 6 inch pulleys that I bought
Compressor is 12.5 inches on the pulley.
what effect would making the switch to a 6 inch pulley on the motor? Rpm wise I can use either and still be within spec on the pump. What will change?
also did get my Nathan K5LA today
csp
Well-known member
Plug your pulley sizes into this calculator if you're asking about what the RPMs will go to.
www.blocklayer.com
Pulleys and Belts - Inch
Visually calculate pulley size rpm belt length and speed wwith animated scaled diagrams - Inch
www.blocklayer.com
I see the rpms arePlug your pulley sizes into this calculator if you're asking about what the RPMs will go to.
Pulleys and Belts - Inch
Visually calculate pulley size rpm belt length and speed wwith animated scaled diagrams - Inch
4 in = 576
6 in = 864
How does this affect the efficiency of the motor? Is slower better for lower amps? Would I be better suited buying a 6in pulley and new belt?
I use to be a dealer so I did not pay retail for it it was a sample we got to see if we wanted to add it to our line. I built a sample installation and it worked well but we never got it out to our customers. I think the retail at the time was around $2000 but that was in 2009 or there about. I would use the Mega fuse I think that they are more reliable. If you look you will see that they use a toothed belt and smaller pulleys to make it smaller.
I did try the 6 inch pulley and after a min or 2 the motor started to smoke so I shut it down ASAP. Does anyone think I need to replace it now? It smoked lightly for a minute or so… It still works but the amperage has gone up from 145 to 175 so I’m thinking I need to replace it…
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Rural53
Well-known member
At ten years old I'm wondering if your Viair 444 is just tired. My on-board air system used two Bushranger compressors. It got pulled out when I sold that vehicle. If I was building that system again I would probably splash out on an ARB twin motor high output (6.1 cfm) compressor or two of the other high output Aussie compressors on the market.
redmondjp
Well-known member
This is where design engineering comes into play. You look at the motor ratings and curves, compressor pump curves, and also figure on losing 10-20% power from the V-belt drive. Also, measuring the external temperature of the motor doesn't tell you how hot the windings are getting internally. When I used to design DC motor drives, we would have the motor manufacturer make us prototype motors with temperature sensing elements bonded to the motor windings. This way we knew how hot we were getting the windings.
Not yet discussed: what effect does drawing 150A or so for several minutes have on the vehicle's electrical system? I can see the alternator and battery not taking kindly to this kind of load.
Remember, there is no free lunch! Somebody's got to pay for the sandwich.
Not yet discussed: what effect does drawing 150A or so for several minutes have on the vehicle's electrical system? I can see the alternator and battery not taking kindly to this kind of load.
Remember, there is no free lunch! Somebody's got to pay for the sandwich.
Thank you for your awesome insights! I am running a HO alternator, along with 2 auxiliary batteries. The current I’m not concerned about. I am wondering what other type of motor would be suited to this project? I haven’t had much luck finding one. I have been able to run the compressor with a 4 inch pulley for 20 mins with no problems continuously. I’m not an engineer so I am just working by trial and error standards. Do you think I should replace the motor?
redmondjp
Well-known member
Does is still function after you let the smoke out of it? Without knowing the specifications and ratings on your existing motor, it is difficult to answer your question. That fact that it ran for 20 minutes really doesn't mean much, as you could have (and I am guessing did) overheat the windings internally. You can get away with that for awhile, until you have a failure of the winding insulation at which point the motor is toast (not economically viable to rebuild such a motor in most cases, when comparing to the cost to buy another one). You may find that a DC motor rated for your compressor pump load, for continuous operation is many times larger (and commensurately more expensive) than the one that you have now.
When you are dealing with a motor, welder, solenoid or similar electrical devices that have windings, the key thing is not to overheat the windings internally. You have a very long insulated copper wire, which conducts heat very well through the wire, but not very well through the insulation. Now you tightly wrap this wire around and around a core (either in a motor or transformer) hundreds of times. The section of wire buried in the middle of the windings has no effective way to get the heat out, other than to transfer it to the wires around it, which are equally hot. So the whole mess heats up, with the inside getting the hottest, as only the outside of the winding assembly can conduct and radiate the heat out to whatever it is contacting. The manufacturer will run tests to see how long under various conditions that the motor can run without exceeding the safe internal winding temperature, in order to provide the specifications for the motor so the designers using the motor can determine if it is suitable for a particular use.
This is why items like motors and transformers have duty cycles. Take a consumer-grade welder for example. Read what the duty cycle is in the instructions. It's probably 10-20%. So 2 minutes of welding, followed by 10 minutes of cooling down so the windings don't overheat. Now take an industrial-duty welder that has a 100% duty cycle. It costs 5 times as much, and weighs much more as well. Why? It has much larger windings and other design features (bigger fans, more airflow around the windings, etc.) to help it dissipate the heat.
So this is why I say that there is no free lunch. The motor you are currently using may only be rated for the load you are applying to it for say 5 minutes, followed by 20 minutes of no use for cooling the windings (this is just a guess for illustrative purposes). Will it run for longer? Sure, but the windings won't like it and their life will suffer.
I used to specify DC electric motors for a major lift manufacturer (scissor and boom lifts). We dealt directly with the DC motor manufacturer who in most cases custom-designed motors for our application. There are several companies that manufacture such motors, such as Advanced DC Motors, D&D Motor Systems, and others. I would suggest looking at their existing offerings to see if they have an off-the-shelf solution which might work for you. Here is a link to an EV supplier which lists various DC motor manufacturers:
Thank you so much. I will check. The motor has been running ok until the smoking started which was prompted by removing a 4 inch pulley for a 6 in an attempt to speed up the motor. I am using a winch motor running 2hp at 1800 rpm. It pulls around 100 amps at 0 psi and 145 at 120 psi. I did add some small holes at the rear of the motor and attach a fan on a timer. The fan runs on startup and continues for 10 mins after the compressor stops running. I will check around for a new motor.
my buddies son has a landscape company, one of his salters has quite large 12v dc motor on it . might look at something like that as they are designed to be more continuous duty than a winch motor or starter motor is
fourjeepin
Well-known member
I have a York and with the hand throttle set at about 3k rpms, it will run a die grinder non-stop. I previously had a Thomas electric compressor. It was pretty slow for airing up tires. I never tried any air tools with it except an impact.
Got both of these in my JK. Great options