UFO politics Keeps his word 12-12 12 Let the games begin.......

[Magluvin]

But the mosfets from the electric bike, IRFB4310, have a typical Rdss of 0.0056 Ohm... supposedly the lowest available in a TO-220 device. Clearly they are fast enough for FM/PWM motor controllers. I wonder just what the sequence of events was that caused the bike controller to fail.


I really like these high-powered "inside-out" brushless motor designs, where you never have to worry about throwing wraps... because the armature is motionless and the "stator" with magnets rotates around the outside of it. Other high-power brushless motors are conventionally built with stationary coils wound like field coils in the case and "armatures" that are just magnets on the shaft. The controllers for these brushless DC motors can do just about anything, from running in either direction, to braking, to regeneration, and many even have variable timing to compensate for varying loads and speeds.

As for blowing the controller transistors, I havnt had any problems, with 3 bikes. ;]

My trek with 500w fr wheel hub motor, 48v, the controller stays very cool. No cooling needed, zipped up in a small bike bag behind the seat post. In fact the hub gets very warm in comparison.
Could be a problem with another part of the controller board.
Could be shorted winding in the hub or cabling where it enters the hub through the hollowed shaft axle. These things are not water proof.
Could be an issue with the hall sensor in the hub. I had one go bad in that motor. It caused abrupt thumping like something was broken mechanically. Replaced and was ok.

Mags

[tinman]

Tinman,

Yes, IGBT's could be used, but device dissipation can be made lower for MOSFETs.  IGBT's typically have a saturation voltage of 2 volts or greater, so 100 amps passing thru a 2V Vce IGBT would dissipate 200 watts of heat.  A MOSFET with a .01ohm RDSon would only have a 1 volt drop across it when fully on and only dissipate 100 watts of heat under the same conditions.  Paralleling MOSFET's reduces the total on resistance, hence their Vdrop, hence total dissipation, whereas paralleling IGBT's does not decrease dissipation (Vce remains the same) but does make all the devices share the total dissipation.   

For high voltage applications, however, the IGBT can be just the ticket, and can be more robust in some applications.  Also, IGBT's are available with and without a freewheel diode across the CE junction and can be useful where the MOSFET's parasitic body diode is not desired.

Most inverter type TIG/MIG boxes use an offline switcher (ie, switch the rectified AC line) to drive a transformer, so the IGBT or similar switching device does not see the full output current due to the  primary/secondary xfmr ratio.  By using HF switching (as in the 20KHz you mention), the transformer can be very small and lightweight compared to a similarly rated 50/60Hz xfmr.

I believe you said UFO emailed you regarding his Prony tests and your assertions relating to his errors, have you heard from him since you performed your tests and made your video?  You are probably correct regarding not seeing him do a comparison Prony test on a non-modified motor.

As for his desire to operate at higher RPM, possibly he is just raising the bar to make testing more difficult, with high speed and complex drive circuits now required to show OU.  He is now discussing a four phase drive circuit, and I don't really see why.  He is discussing asyncronous operation, and originally, I thought he wanted to only power a winding briefly as commutation ocurred and be synchronous to that commutation.  At the higher RPM, that would require pretty fast switching.

Again, if his concept is sound, one has to wonder why all this could not have been done with a smaller modified motor with lower current requirements to make testing and drive circuits much easier for a proof of concept (and less costly for replicators).

PW

Hi PW
No -i never heard back from him again.I recieved an email from youtube showing me a comment that had been made by UFO.But when i went to my video to read the whole comment-he had removed it.
I guess he went and redid the calculations i did on the video,and worked out where he went wrong.

I see that the prony brake testing has gone dead silent over there.
I thought he had a new setup all ready to go?
I see a trend there with UFO and his testing.

First test useing a generator driven by his motor driveing a couple of light's-overunity galore was the cry.
Then questions were asked as to how he came about his measurements-then no more test with that setup.

Second test useing prony brake setup-resulting in another overunity claim.
Once again questions were asked and the test i did aswell,and put forth my results-no more prony brake testing.

I think testing should be done very carfuly,and no claims should be made until you have given others a chance to replicate and test to confirm result's.
Or have a third party test the device and confirm the result's.

He is makeing things that hard to replicate now,it will be hard for the average joe to build the thing.

If he is so sure that his prony brake test showed overunity,then why not just persue that avenue?
I'll give you one guess why.

[picowatt]

Hi PW
No -i never heard back from him again.I recieved an email from youtube showing me a comment that had been made by UFO.But when i went to my video to read the whole comment-he had removed it.
I guess he went and redid the calculations i did on the video,and worked out where he went wrong.

I see that the prony brake testing has gone dead silent over there.
I thought he had a new setup all ready to go?
I see a trend there with UFO and his testing.

First test useing a generator driven by his motor driveing a couple of light's-overunity galore was the cry.
Then questions were asked as to how he came about his measurements-then no more test with that setup.

Second test useing prony brake setup-resulting in another overunity claim.
Once again questions were asked and the test i did aswell,and put forth my results-no more prony brake testing.

I think testing should be done very carfuly,and no claims should be made until you have given others a chance to replicate and test to confirm result's.
Or have a third party test the device and confirm the result's.

He is makeing things that hard to replicate now,it will be hard for the average joe to build the thing.

If he is so sure that his prony brake test showed overunity,then why not just persue that avenue?
I'll give you one guess why.

Tinman,

One would have thought that UFO would have repeated his Prony tests comparing a modified and unmodified motor just to prove to everyone he was correct.  Possibly he did perform those tests and did not like the results, so chose to just move on and forget they ever happened.  Of course, that would put everything into a completely different realm with regard to integrity.

PW

[TinselKoala]

It is very common for people to "bugger" the scientific method in at least five ways:

0. No well-specified and potentially falsifiable hypothesis is put forth.
1. Experimentation is done _not_ in an effort to disprove one's hypothesis, but rather to _demonstrate_ its "correctness". That is, only confirmatory experiments are performed, not ones that have the potential to falsify the hypothesis.
2. Improper "control" experiments, or none at all, are done.
3. Testing methods that show OU are not validated by performing the same tests on known non-OU systems, nor compared with other, known to be valid, test methods.
4. Data that doesn't fit with the investigator's desires or preconceptions is simply discarded and/or not reported.

We see these five "fails" illustrated quite well currently, in UFO's work and also in the work with the induction cooking hobs.

These fails have little to do with instrumental or measurement errors, rather they have more to do with philosophical attitudes.

It's refreshing to see that Tinman isn't falling into these same pitfalls.

[ramset]

""WE Don't need no Stinking Measurements"" [Al Pachino I think?}

The Loop.............[or a reasonable facsimile [sort of] ]

http://www.energeticforum.com/renewable-energy/11885-my-asymmetric-electrodynamic-machines-118.html#post221530