Low Cost Fuel Project

Scott & Heather · February 02, 2012, 07:16:10 AM

As some of you know, I've been experimenting with running our 6v92 mech. injection coach on waste motor oil. So far, I've run approximately 2000 miles on at least a 70% blend of WMO and 30% diesel. I thinned out the WMO with 5% regular unleaded gas (RUG), filtered it through a 5 micron filter and went through probably 6 or 7 waterblock filters and used a water absorbing sock in my barrel to soak up the rest. The only noticeable side effects of running WMO were a quieter (less clack) engine and heavier smoke at idle. Note that in heavier, I mean a haze that might be created from a car that burned oil. Nothing obnoxious. On straight diesel, my coach doesn't smoke at all at idle once warmed up.

This being said, I have moved on to a better process utilizing a centrifuge system from PA Biodiesel. I have spent several months building a mobile centrifuge rig that sits inside one half of my front luggage bay. Performed initial tests over the last couple of days and have tweaked and tuned out problems and now I'm down to one last issue. I'm hoping someone on here has electric motor experience. My 1/2 HP Marathon Electric motor appears to be nearly new (it came with the used centrifuge kit when I bought it online). It is connected to an Oberdorfer pump and the pressure necessary to spin the centrifuge is 90psi. I have a bypass valve that stays open while the oil is pumped through a heating element in a continuous loop, and then when it reaches 120-160 degrees I want to slowly close the bypass valve and run the oil through the centrifuge. As soon as I do this, the motor chugs, then thermally kicks off. Stays off several minutes before kicking back on again...then it chugs, then the process starts all over again. I never can get past 40-50 psi. Is this the sign of a bad motor? I'm on a budget, so I don't want to just be a parts changer at this point. Any advice would be welcome.

-Scott

Len Silva · February 02, 2012, 07:26:43 AM

Without knowing more about it, my first guess is that it is simply not enough motor to do the job.

Jeremy · February 02, 2012, 07:26:58 AM

If the motor 'should' have sufficient power to run the centrifuge, but is stalling as the load increases, it's power supply perhaps can't supply the current it's trying to draw. Might even be a phase issue if the motor is intended to be run on an industrial supply.

Jeremy

AndyG · February 02, 2012, 07:42:42 AM

It depends on the size of the pump to are trying to run but I think that your electric motor is to small for the job. It takes a lot of power to make 90psi even with a small displacement pump. Check with the pump manufacturer to see what size motor they recommend. Another thing to remember is that all 1/2hp electric motors are not alike. Some a light duty motors designed for short run times and light loads. Some motors are much heavier and made for running continously at full load = 100% duty cycle.

chev49 · February 02, 2012, 07:57:05 AM

If I had the same motor issue, i would assume that that the motor needed to be larger. That being said, there are other issues that might be the problem.

artvonne · February 02, 2012, 08:01:25 AM

My hat is off to you for trying, but in all the reading ive done I really believe much more research is needed. Seems many of the old MB 300 veggie burners are just being ran into the ground and left for scrap after the motor is destroyed.

We must all realize, different grades of fuel have different autoignition temperatures and burn rates. Many mechanical diesel manuals specify different injection timing for different Cetane numbers. Different types of fuel (different viscosity) also often require a different injector nozzle/spray pattern. Pumping engine oil or veggie through diesel fuel injectors and not changing timing can cause trouble.

I'm not saying it wont work, or that you wont have good luck, but these are big expensive engines and 2000 miles isnt a very long ways to show any real results. If its not burning the fuel correctly it can build coke deposits quite rapidly and it will destroy the engine.

That said, you should be able to measure voltage and amperage on the running motor. Those numbers should tell you if the motor is being overloaded. Also, most pumps have their rating available somewhere, perhaps a data plate showing how many gpm at such and such psi. There are tables you can Bing ( I dropped google) to show general formulas for the hp required to produce x gpm at x psi.

Scott & Heather · February 02, 2012, 08:07:51 AM

Len & Chev49: I'm thinking the same thing... $:-\$
Jeremy: This is also a possibility. The motor is meant to run on 110 and I have it plugged into a dedicated circuit, but I may need a bigger extension cord.
AndyG: The motor is rated for continuous duty. PA Biodiesel has tested the motor/pump setup and it should be working fine...but obviously it's not.
artvonne I've also seen vehicles and generators run successfully on WMO for quite some time. Right now, my coach costs nearly $1 per mile to run. If I can drive 5000 miles...or even 10,000 miles on this stuff, it will pay for an engine when it goes "poof".

That being said, I am past the point of being convinced out of doing it, I just need help with my motor chugging

I can't tell what model of Oberdorfer pump I have, but here's some photos:

Sean · February 02, 2012, 08:14:26 AM

I agree with Len and Andy, you probably have too small a motor.

That said, you may also have too long a run of too small a wire gauge supplying it with power. If this is the case, then as the load builds, the voltage at the motor will drop, causing a vicious cycle wherein the motor now draws even more current, quickly heating the thermal overload and tripping it.

Try moving the whole apparatus closer to your electrical panel so that the circuit length is shorter. If that fixes it, then you'll want to run a heavier circuit to the pump location.

On a completely separate note, I will suggest that you are taking a huge risk here. Your setup will only remove suspended particulates from the WMO. It will leave behind dissolved solids as well as other chemicals that can not be removed by filtration alone. Among these are a number of corrosives or substances which become corrosive during combustion. In time, these can eat away at rings, liners, and injectors. This is the reason Detroit explicitly prohibits use of WMO in their engines, as do many other manufacturers. The $10-$15k it would cost to replace those items can easily reverse years worth of fuel savings. Commercial refiners who process WMO into fuel use chemical and fractional distillation techniques in addition to filtration to produce clean fuel from WMO.

Also, remember that you are required to record the quantity of this homemade fuel that you consume in your vehicle and pay the federal road fuel tax on it, and most likely state tax as well depending on your state. This will run you anywhere from $0.26-$0.62 per gallon, so remember to include that in the operating costs of your WMO processing when figuring your cost savings. You can avoid this problem by restricting its use to your generator and heater (if so equipped).

-Sean
http://OurOdyssey.BlogSpot.com

Len Silva · February 02, 2012, 08:16:23 AM

I would first check the voltage at the motor under load, be sure you are using at least a 12 ga cord, as short as possible.

Second, try reducing the pulley size on the motor by half. That should prove the problem for you.

Sean · February 02, 2012, 08:20:14 AM

Quote from: Scott Bennett on February 02, 2012, 08:07:51 AM
... The motor is meant to run on 110 and I have it plugged into a dedicated circuit, but I may need a bigger extension cord.
...

I see you posted while I was typing my previous reply. Yes, the extension cord could be a big issue.

In looking at the photos, though, I see the motor is rated at 208 volts, but you say you are running it on 110 (by which I am guessing you really mean 120). Perhaps this is the problem? Did you rewire the motor for 120? Or am I misreading the rating plate?

-Sean
http://OurOdyssey.BlogSpot.com

chev49 · February 02, 2012, 08:22:19 AM

Wonder what percentage of people would log and send in any more money to govt?
Don't forsee much of that happening...

Course, the govt now wants everyone to spy on their neighbors and report them...

sorry this is off topic a bit, just reading earlier post...

belfert · February 02, 2012, 10:47:23 AM

I think Sean is onto something with the 208 volt comment. It appears this is a 208 volt only motor. I am surprised it is running at all. A motor that can be wired for either 230 or 115 volts would usually say something on the label like 115/230 volts.

luvrbus · February 02, 2012, 11:14:52 AM

Those pumps are very sensitive to shaft speed pumping liquids like you 1150 rpm is about tops or they start to seize up been my dealing with those but I think the motor is too small try changing belt speeds

bevans6 · February 02, 2012, 12:55:57 PM

My dusty memory is telling me that 208 volt motor is an industrial motor designed to run between two phases of a three phase industrial power supply. I'd stop fussing with it and get another motor. It might draw too much current if you run it on 220 volt household supply, and possibly overheat. If you are trying to run it from 120 VAC, it will be developing around half power, maybe less... It's been a really long time since I could figure out that sort of electricity.

Brian

Sean · February 02, 2012, 02:21:38 PM

Quote from: bevans6 on February 02, 2012, 12:55:57 PM
My dusty memory is telling me that 208 volt motor is an industrial motor designed to run between two phases of a three phase industrial power supply.

Your memory is only a little dusty. 208 is the phase-to-phase voltage of a 208/120 three-phase wye power system, which is common in office buildings, light industrial, and other commercial properties (including, BTW, some campgrounds, which I have written about before).

Quote
... It might draw too much current if you run it on 220 volt household supply, and possibly overheat.

Actually, it's worse, because there is no such thing as a "220" supply -- it's really 240, which is way too high for a motor rated at 208. Many, many motors carry dual or even triple ratings, or a range. For example, almost all household appliances that expect this sort of voltage are rated 208-250v. RVs using 50-amp supplies are also required to accept 208-250v. But this motor appears to carry only the single rating.

Quote
If you are trying to run it from 120 VAC, it will be developing around half power, maybe less...

Actually, much less. Power is proportional to the square of the voltage, so running a 208-volt device at 120 volts would give you just one third the power. The motor, while struggling to produce the desired output, will trip the thermal cutoff on overcurrent.

This is the reason I brought it up...

-Sean
http://OurOdyssey.BlogSpot.com