Is this the first selfrunning overunity motor w/o batteries ? Mike?s motor

[gyulasun]

Data sheet: http://www.irf.com/product-info/datasheets/data/pvn012apbf.pdf

Specification summary:
50 Milli ohm on resisistance (lower than many mechanical switches!)
4000 volt isolation
4 amps max continous load  AC or DC  (8 amp pulse)
Requires only 5 ma turn on current (behaving like small LED)
Cost is approximatly $5 US

Hi Derrick,

I agree, this photovoltaic relay is a very useful-looking switch for many places but I do not think this is the best or one of the best switches for the windows motor.  Why?

Its biggest drawback is the output voltage range is +/- 20V DC or AC peak voltage which is way too low for inductive switchers. Here we must have some hundred volts switching capability at least.
Another drawback ( though at low rotor RPMs it is tolarable )  is its low switching speed: see the 3 mili_sec turn-on and 0.5 mili_sec turn-off time.

A member here, fesearcher posted a solid state switch circuit, see this file  solid_state.pdf  at this same thread here:

http://www.overunity.com/index.php/topic,1988.msg24204.html#msg24204 

which I consider one of the best and (cheap) solution to this problem.  It is true its driving circuit needs an extra CMOS integrated circuit but offers much higher switching voltage capability (actually you can decide the MOSFET types for your needs!) and can be much faster than the photovoltaic switch.

Regards
Gyula

[derricka]

Hi gyulasun,

You are correct about the switching voltage, so for motor designs needing to handle high back EMF, I too would choose a different version (International Rectifier does offer versions of this relay going up to 400 volts, tradeoff is higher on resistance). As for the switching, speed I also agree it is slow compared to a MOSFET but plently fast for testing most of the motors being built here (certainly mine anyway). I just love them because they are so easy to use! Speaking of MOSFETs, do you think some of these circuit designs would benefit from using them instead of the bipolar transistors currently being used.? I know there are some tradeoffs here too, but I have always used MOSFETs for my PWM electric helicopter motors and always find them preferable to bipolar transistors.

Derrick

[SPP-48]

1 coil lays one side of the Armeature spindle and the other coil the other side.
use Insulation tape to bind together.as in Mikes picture.

Connect the 2 main windings in parralel and solder the ends
Connect the 2 generator coils in series
connect the 2 Trigger coils in series.

Thats it done.

Hi Peterae

It looks like I may have missed something major. I never realised that Mike used 2 separate lots of coils. I went back to the first post on this thread and looking at the photos of Mike's motor again, you are right. It does look like two coils side by side.

Many thanks

SPP-48

[gyulasun]

Hi gyulasun,

You are correct about the switching voltage, so for motor designs needing to handle high back EMF, I too would choose a different version (International Rectifier does offer versions of this relay going up to 400 volts, tradeoff is higher on resistance). As for the switching, speed I also agree it is slow compared to a MOSFET but plently fast for testing most of the motors being built here (certainly mine anyway). I just love them because they are so easy to use! Speaking of MOSFETs, do you think some of these circuit designs would benefit from using them instead of the bipolar transistors currently being used.? I know there are some tradeoffs here too, but I have always used MOSFETs for my PWM electric helicopter motors and always find them preferable to bipolar transistors.

Derrick

Hi Derrick,

Well, the question is I think how closely can you make a solid state switch to a conventional mechanical switch?  (current, breakdown voltage, speed, isolation resistance the main requirements) .
MOSFETs are good but suffer from the inherent body diode between its drain and source electrodes, this sometimes is good to have but in most of the cases a big drawback.  Also, MOSFETs have a big input and output capacitances that increase input drive need and may contribute to poor switch-off isolation.
Regarding bipolar transistors, basically they are also useful switchers and I do not think they should ALWAYS be replaced by MOSFEts. It all depends on the application: what is to be switched? This may sound way to simple but it certainly needs practical experience what to choose.  I think in the window motor case here the 3 bipolar transistors reflect back the state of the art of the 80's and surely perform fine.  It is another question for instance if you wish to use Neo magnets instead of the ceramic ones, the induced voltages may be increased so those bipolar types need revising to withstand higher voltages than the present ones.  And regarding Mike's solid state relay, the circuit from fesearcher here is a perfect substitute I think.
Yes I understand IR have photovoltaic relays for 400V and they are very convenient to use. They are also good here instead of the SST.

Thanks,

Gyula

[z_p_e]

1 coil lays one side of the Armeature spindle and the other coil the other side.
use Insulation tape to bind together.as in Mikes picture.

Connect the 2 main windings in parralel and solder the ends
Connect the 2 generator coils in series
connect the 2 Trigger coils in series.

Thats it done.

Hi Peterae

It looks like I may have missed something major. I never realised that Mike used 2 separate lots of coils. I went back to the first post on this thread and looking at the photos of Mike's motor again, you are right. It does look like two coils side by side.

Many thanks

SPP-48

SPP-48.

How can you tell for sure? It would be impossible to tell from the two pics we have of his motor. Also, in all the attempted replications of this motor I have seen, they all look like the coils could be two separate coils, but that is because the coil is being split before it goes around the axle, so for about half of one complete winding, the one coil mass will look like two.

Mike said the coils were wound bifilar/trifilar. You should probably stick with that. Also, I wouldn't be assuming anything else regarding the coil construction. He has given the wire sizes and resistances for all 3 coils. Generator and Trigger coils are the same. Any deviation from that and the chances of successful replication deminish accordingly.

Darren