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

[picowatt]

Ian,

The very first post on this thread is a link to someone claiming "overunity galore".  However, subsequent videos related to that claim did not demonstrate OU.  That is not exactly being "negative", but merely an observation.

The concept of OU is something like more power out than in, and if it is related to a motor, then the output will be mechanical rotation at a given torque and RPM. 

If someone is going to design or build a motor that is to be more efficient than current designs, would it not be logical to first construct or obtain the equipment necessary to measure the mechanical output from both standard and modified motors for comparison and quantification? 

I read all 112 pages of the thread linked to in the first post and did not see any measurements of input power (electrical) versus output power (mechanical).

Although he needed a smoother acting brake setup, poster Turion over there came close to building a Prony to measure the RS motor output/efficiency but it seemed his efforts were less than encouraged.

Again, if anyone has actually performed electrical power in versus mechanical power out measurements that I either missed in the thread I read or that are posted in an alternate thread, please post a link or direct me to where such measurements can be found.

Far from being "negative", I encourage anyone performing UFO's motor mods to construct or obtain a dynamometer of some type to allow measurement of power in (electrical) versus power out (mechanical).

How else can any improvement in efficiency or OU be measured or verified?

PW

[TinselKoala]

@MH: That's an interesting place to look in the thread. I see that Ian has had some difficulty with the mosfet PWM module......

PS

Perhaps I could try it with only 1 or 2 Mosfets as it is very expensive destroying 6 at a time

Kogs

Perhaps you could try it _without_ the expensive NTE-brand mosfets and use the IRF equivalents which are about one-third the price or less. As I noted before the NTE mosfet sells for between 6 and 10 dollars each depending on the source, and the equivalent IRF mosfet can be had for between 1 and 2 dollars each.
NTE brand components are always much more expensive than the actual part they replace. The only time to deal with NTE  (ECG) is when you absolutely cannot find a substitute component anywhere else. The choice of 6 NTE brand mosfets in a circuit that is sure to blow them frequently is a mistake, when there are IRF power mosfets that outperform the specified NTE parts and are much cheaper.

(Just think.... if we here had gotten involved sooner we might have been able to save Kogs some money and frustration. It's all Ramset's fault for not opening this thread earlier !      )

[TinselKoala]

Is there a difference in behaviour between a commutated DC motor driven by straight ("linear") DC power, and the same motor driven by a pulse width or frequency modulated controller?

What happens to the  RPM and power consumption in each case, when the motor is loaded or even stalled by heavy shaft load?

[MileHigh]

TK:

I have some related questions.  What happens when you power a motor with a current source when the motor is normally supposed to be powered by a voltage source?  Will that sometimes induce very high voltage surges on the power leads going to the motor and will that be a potential shock hazard?  Look at the example of when the commutator brushes disconnect the armature for a short period of time as the rotor turns.  The current source will generate arcing.  Is that arcing worse than the commutator arcing that you normally see in a DC motor?  Will that double the amount of arcing and will that shorten the life of the commutator and the brushes?

Also, could this explain the blown MOSFETs?  Let's assume the motor is just starting up and the RPMs are very low.  Let's assume the coil is fully energized and starts its discharge into the motor.  Let's assume that the brushes and commutator go open circuit and the open circuit time will be longer because the rotor is turning slowly.  Will that set up a "perfect storm" and allow the fully energized coil to discharge through the MOSFETs and blow them?  Naturally I am assuming that there is no protection device across the MOSFETs in this case.

MileHigh

[TinselKoala]

Current source, voltage source?

Voltage is the "pressure" that pushes charge through an impedance. Current is the time rate of flow of charge. Could you tell me the difference between a "voltage source" and a "current source"?

My bench power supply has a current-limiting mode. You short together the output leads and set the current limiting pot to the desired short-circuit limiting current. Then the power supply regulates its _voltage_ to avoid exceeding the limiting current when the load's impedance drops.

A constant-current supply will vary its output voltage as the load's impedance changes, in order to maintain a constant current in the load.