Retested Hughs 4 ft - Garbogen.

[Jerry]

I've set up a new test on the bench.

This time I'm using a 260 volt PM servo motor.

I don't have any other specs on this drive motor other then its 5" diameter and 12" long.

It has a 5/8" shaft protruding from each end.

I've mounted a bearing and support mechanizem at each end.

This alows the motor body to rotate freely.

This could be a problem except I've mounted a bar to the motor body. This metal bar alows me to atach a small fish scales between it and the base  that complete test assembly is mounted to.

I've also added an amp meter and a volt meter directly to the drive motor armature.

The fish scale shows the amount of LBs depending on the load on the motor.

A couple more pictures.

Heres what I mesured.

         Hughs 4 ft PMA                        Drive motor                    

  Amps to battery  rpm                 Amps     Volts   Watts   Fish scale reading

   2.5             367                  1       75.6     75.6         0 LBs

    5              428                  1.5     90.6     135.9       .5 LBs

   7.5             469                  2       100.4   200.8        .75 LBs

   10              561                  2.75    121.6   334.4        1.5 LBs

   15              704                  4       157.4   629.6        3   LBs

     Garbogen  PMA                             Drive motor

  Amps To battery   rpm               Amps     Volts    Watts   Fish scales reading

 2.5               432                 1        86.9    86.9           0 LBs

  5                492                 1.2      101.1   121.32        .25

 7.5               546                1.7      113.9   193.63        .5 LBs

 10                624                2.2      128      281.6        1 LBs

 15                725                3        155.6    466.8        2.25

 I don't know guys? It still apears the disc rotor machine requiers more power to operate at the same output.

I don't know if this is a good indicator or not but it sure apears that way on the surface.

Again the wind tunnel test will show the diferances.

The no load test were identical.

                          JK TAS Jerry        

[Flux]

well done Jerry.

Can you give us the horizontal distance from the hook of the scale to the centre line of the motor then we can calculate input power direct.

There is a slight issue with your 2.5A reading. The torque can't be zero at this point.

You may need to balance the torque arm it may have some unbalance biassing it to zero at this load rather than being balanced at no load as it should.

From the figures given it seems as though the axial is less efficient than the garbogen but I would like the torque arm length to get to true input watts before making any more comment.

Flux

[ghurd]

The torque 'Reading' can be 0.

Those scales are far from correct.

A reading of 1 is probably not half of a reading of 2, or 1/4 of 4.

They do register the same number with the same weight quite repeatably.

If one is reading 2, and the other is reading 2, then they are pulling the same.

The long scales are a lot more accurate.

Cabela's has a digital on sale for $15. (item #8IS-018215)  Mixed reviews.

G-

[Jerry]

Hi Flux.

The arm lingth from center of the motor is 11". I measured the motor diameter and its 4-5/8".

This scales is cheap. They have a better one I'll pic up today. It has a rotor scale and a pointer.

I think it will read the lower #s with more detail and better accuracy.

The no load test showed Garbogen at 150 volts and .3 amps on the drive motor and 784 rpm at the Garbogen.

Hughs 4ft 150 volts and .4 amps on the drive motor and 785 rpm at Hughs 4 ft.

I'll pick up the better scales and retest.

                          JK TAS Jerry

[Jerry]

I could measure the weight of the arm at the hook on a postal scales so that weight could be deducted from the fish acales reading.

                                JK TAS Jerry

[ghurd]

Maybe a large weight on the postal scale.

String from arm to weight.

If weight is 5 pounds, and under load reads 3 pounds, then the pull is 2 pounds.

Know what I mean?

G-

[pepa]

    extend the extention to the front side of the motor and have it press down on the scale. i have a large supplu of speaker magnets. are they better quality than regular earth maginets, like the micro donuts? thanks pepa

[tanner0441]

Hi

You could also buy a cheap electronic kitchen scale and have the arm apply presure, you could have lbs or Kgs at the flick of a switch, and if something jams the motor case won't rotate half a rev in the oposite direction. Make the arm 1ft long from the motor center line and it will read directly in lbs/ft.

Brian

[Flux]

Thanks Jerry.

Sorry I also need the speed of the drive motor for each reading. I just checked your figures on the assumption that the pulleys were the same size and it makes the garbogen 100 % efficient.

The drive motor must be going faster than the alternator.

Flux