No announcement yet.

Lockridge Device - Peter Lindemann

  • Filter
  • Time
  • Show
Clear All
new posts

  • My small dynamometer with a range of less than 2 mNm to over 110mNm.

    This dynamometer uses a small DC motor to act as the absorber. The motor to be tested is mechanically linked to the absorber by a series of driveshafts and a coupler. The absorber is mounted in such a way that it is allowed to rotate. An arm is then mounted to the absorber. As load it added to the absorber, torque is created in the arm. The arm pushes downward on a precision balance. A hall type sensor is use to measure the shaft rotation. A computer is then used to control and monitor the dynamometer as well as display the data.

    Wiki is a good source if you would like more details about how a dyno like this works.
    Dynamometer - Wikipedia, the free encyclopedia

    The following shows the two support bearings for the absorber along with the coupler. The coupler will have two small magnets mounted inside.

    The torque arm, modified coupler with magnets, absorber and the counter balance for the arm.

    The base with the bearing supports, torque arm limiter and hall sensor mount. The threaded rod holds the bearing supports in place for welding. The bearing holes are undersized and line bored after welding.

    These are two of the motors I plan to use to test the dynamometer along with the motor mount. The mount was not welded to the base to allow ease of motor change out. The motor on the left is from a VCR and was used to drive the tape spindle. It is rated for 6V operation and has very low torque. On the right is a hobby motor. It has much higher torque and capable of running at 20,000 RPM.

    The dynamometer and balance with the hobby motor installed.

    Looking at pulls with the 6V VCR motor. RPM is shown. Motor supply voltage was set to 4V then incremented in 1V steps to 14V.

    Looking at torque for the same pulls.

    Here the data is overlaid to show each pull. Notice that the shaft speed increases at the end of each consecutive run as the voltage increase. The system is not yet closed loop.

    Showing motor output power in Watts for all 11 pulls.

    The 6V VCR motor was ran again at 6, 12, 18 and 24V. The following set of plots show the effects on the speed, torque and output power.

    This data was taken from the green hobby motor. The ratio of output to input power shows that the motor is most efficient in the area left of the peak output power. This matches with the manufactures data. Currently I have not pushed this motor to its limits because of the vibration at these higher shaft speeds.

    If your considering building your own dynamometer, I have created a list of my concerns with this setup.

    1) Pick a better absorber, or make one from scratch. The rear support is just not stable enough. I had some ideas on what I wanted to measure so I sorted motors to find something in this range. The motor's bearings, the fact it has brushes, balance, etc all make this a bad idea. Designing something to do the job right would be better time spent.

    2) Use better construction practices. While I knew the aluminum would warp during welding, I had left the bearing holes 10 under. After welding, I then borded them with a reamer. This is fine, but the small amount of warp in the base causes drag when it is clamped to a flat surface. IMO, don't weld. Machine the bearing support from one piece and then bolt it to the base.

    3) Use C -clips to hold the bearings. The setscrews cause the bearings to distort and add drag. It does not take much.

    4) Make sure that the bearings you use are up to the task. This dyno was made from scraps. This included the bearings that came from a small stepper motor I had tore apart. This was a poor choice.

    5) With a 6" torque arm, make sure the shafts are near perfect. Any errors here are just multiplied by the arm length.

    6) Figure out a way to balance the rotating parts. I have some ideas, but nothing proven.

    7) I had tried to keep the rotating weight down. A flywheel may help to reduce vibrations.

    8) The coil type of coupler I used may not be the best choice. Any missalinment adds drag.

    9) Design a better mount for the test motor. The block is OK, but imagine drilling holes for all your motors. Maybe something with micrometers to fine tune the XY&Z.

    10) Think about adding a closed loop control system. This system would have it, but I think it has enough problems that it does not warrent any more time spent on it.

    11) The power supplies compensation lines need to be connected to the motor and the cable sizes need to be increased.

    12) Use a larger heat sink for the absorber's FET drive.

    13) Come up with some sort of air duct system for the motor and absorber as well.
    Last edited by joeqsmith; 03-11-2011, 02:48 AM. Reason: PW asked that a description be added.


    • This is the new DC-DC converter used to drive the motor as well as the current control for the absorber. Both are controlled by the computer.


      • 4 coil

        Hi mark, the 1st winding was with 4 coils didn't work..
        The next winding will be two 23 ga wires one coil filled slot

        Last edited by goreggie; 04-03-2011, 11:07 AM.


        • Hey Reg,

          The 4 coil set up should have still worked. If you wound all 4 coils with 1 piece of wire it gets very confusing which way to wind. The first rotor I wound I wanted to wind 4 seperate coils with 1 wire but wasn't sure which way to wind so I just wound 2 seperate coils with 1 wire. All the rest of my rotors were wound with the "zig-zag" method.

          Nice Caps! Where did you get them and how much. I cant seem to find a good place to get high voltage high capacity caps at.

          Keep us posted.



          • Hi mark I got it off of ebay paste, 4700uF 450V Hitachi capacitor TUBE AMP CAP
            and it will come up. I paid $29.00 dollars each
            On the 4 coils it was wound with one wire but it didn't run on 24 volts.. I think it needed higher voltage so I stopped. Waiting for the new one coil wound hopeful any day Reggie


            • Originally posted by Peter Lindemann View Post
              Neither John Bedini nor I have ever seen a real "Lockridge Device".
              Wow, ouch.

              In all of europe, and all the military personal returning to USA,
              no one ever smuggled one home to toy with for gosh sakes ?

              I thought I read somewhere someone had smuggled one home...

              They made these in a factory too, no data about that even ?

              This is a sad state of affairs, how do we even know it was real then ?

              I'm not trying to be fickle here, but is there any confirmation available ?


              • Originally posted by WeThePeople View Post
                Wow, ouch.

                In all of europe, and all the military personal returning to USA,
                no one ever smuggled one home to toy with for gosh sakes ?

                I thought I read somewhere someone had smuggled one home...

                They made these in a factory too, no data about that even ?

                This is a sad state of affairs, how do we even know it was real then ?

                I'm not trying to be fickle here, but is there any confirmation available ?
                Watch John's Energy from the Vaccum video and see Peter's lecture video plus do some basic reading and you will find the answers to all your questions. There is no 100% proof that it existed but all the evidence is quite good and there would be no point for all the people who owned one to lie about it.


                • Self Running Motor

                  "Soon" goreggie

                  "It can be built. We are discussing just that in this thread. Read through we are working not wondering."



                  • shorting coil

                    Inspired by Woopy, I did a brief experiment with a shorting coil on my 3pm, reported here:

                    Yahoo! Groups

                    400V spikes (on the 'scope, which doesn't even capture half of what's going on), 100V into a 10uF cap in mere moments. More experimentation required...



                    • back to back observations

                      I tried several back-to-back experiments.

                      1) My modified motor coupled to an unmodified motor of the same kind acting as a generator. At 36V, the combination spun at about the sweet spot for efficiency for the modified motor (3750 RPM). The generator output was attached via a FWBR (UF4007's) to a 3300uF cap (400V). The cap charged to 12.9V and held.

                      E = 0.5 x C x V^2 = 0.5 x 0.0033 x 12.9^2 = 0.2746J

                      2) Same setup, but with the recovery brush pushed through a FWBR (UF4007's) ganged in parallel to the generator FWBR output, into the 3300uF cap. The cap charged to 20.78V. E=0.7125J.

                      3) Using thee combined E from (2), I calculated the capacitance which should have resulted in 36V of charge. C = 2 x E / V^2 = (2 x 0.7125) / 36^2 = 1100uF. I replaced the output cap with a 1,100uF cap (35V) and ran the machine.

                      The cap charged only to 20.94V.

                      Not what I expected. Comments?

                      4) I removed the stock armature from the generator and replaced it with my 1st modified armature (1 coil, 18awg, commutators lathed after previous abuse). The 1100 uF cap charged very quickly to 19.3V, i.e. almost as high as that for the unmodified armature with a full set of windings. The combination produced immense vibration, and I terminated the run quickly. Clearly, any further investigation of this kind of combination requires a flywheel to damp out the mechanical imbalances.



                      • flywheel calculation questions

                        Would someone check / verify / comment on my calculations below? Am I going about the flywheel estimation correctly? My gut says that a 3" flywheel, 2lb in mass, seems somewhat heavy for a DC motor of this size, but I've never really thought much about flywheels...

                        My modified motor appears to hit its sweet spot at 36V, 3750 RPM, producing 35 ft-lb/sec. (according to my rube goldberg dynamometer).

                        From this chart

                        foot-pound per second to joule per second - power conversion table

                        I convert 35 ft-lb/sec to 47.454 J/s as the sweet spot.

                        Using the flywheel calculator


                        I get a few flywheel options:

                        rpm=3750, mass(oz)=30, diameter (inch)=3, J=47.6
                        rpm=3750, mass=16, dia=4, J=45
                        rpm=3750, mass=10.5, dia=5, J=46.3



                        • Update

                          I have fixed the commutator (polished with emery cloth) and have rewound one coil back on. This time I tried the 3 to each side, but I also switched the crossover top and bottom. This made room for over 100 turns of 24 or 26 ga. wire with an impedance of 2.9 ohms . I will take some pics in a few and add them. I still need to clean up the brushes as the run brushes have some burning and pitting. Also should I put a second coil on the motor or run just one? Peace


                          • thanks for great information

                            Hey Folks,
                            Im new to this thread and first let me applaud everyone on the dedication to and sharing of knowledge for this project.
                            I purchased the Electric Motor Secrets part 2 DVD last week and watched it several times. Peter, thanks for your work and the information in that video, really great stuff.
                            Matt, thanks for the information you posted, clearing giving those of us just starting out a tremendous boost on getting to where you are. I was going to order parts at the end of last week and im glad I found your post before i did. I hopefully can acquire my parts this week and start joining in the fun.
                            best of luck to all


                            • size of field and stator design

                              One of the things that I just thought of. In a video by, I think it was Norm Wootan, he mentioned that the E. V. Gray motor that the field and stator was of the same weight and winding design. If the two windings and assemblies are different then after the pulse the collapse or BEMF effect will be out of sync. One collapsing more or faster than the other. The difference after one collapses will cause an attraction that reduces the work output. I believe that this is needed to obtain the maximum work from the pulse input.
                              We need another N. Tesla! Maybe one of us.


                              • Food for though

                                Hi there everyone
                                After doing lots of tests with 10,12,16 commutator sections it seems to me that a 20 com would be the best to start with.To get a 10% duty cycle you need 1 com section firing twice per cycle on a 20 com setup.10 com = 20% duty cycle etc. Every time i tried to get over 24 volts i think the current starts to catch up causing feedback to the brushes and no recovery with a duty cycle more than 10% .The motors ive been using = windscreen wiper , radiator fan , boat winch , this is all i could get my hands on at the moment (no spare money) so i'll have to wait . Peter said start with something about 1/2 horse power(373watts) which is spot on i think plus it will have a good set of high current brushes that will put up with high voltage pulses. On a hole these smaller motors preformed very well (good torque) but are limited to 24v when modifications are done to the rotor with minimum recovery from the back spike because of there long duty cycle .Most of the time i just shorted the recovery brushes with a diode and a bulb that didn't light to smooth things out. This is just what ive found with my small setups at the moment .Any thoughts anyone. Jason