Pierre's 170W in 1600W out Looped Very impressive Build continued & moderated

listener192 · May 31, 2018, 10:55:29 AM

Here is what you get from one set of 5 coils on a 30 slot stator at 25V using the BTN7960 Bridge boards.
When in registration, the inductance of the rotor reduces the current down to about 3A peak. About the same result as the L298N boards.
The BTN7960's don't even get warm.
Increasing the gauge of the wire would reduce coil heat and allow more current at 25V (if required).
L192

Jeg · June 01, 2018, 03:51:05 PM

Quote from: listener192 on May 31, 2018, 08:16:37 AM
A cap of that size will be between 150uF and 330uF.
The voltage rating is that of the cap seen in video 1.I know the size of the, cap as I know the size of the Crydom FWBR along side it.I planned to try 330uF next, unfortunately the relays have failed again so that wont be possible.
The thought was that the half wave ripple may be significant to operation, after all why have such a low value cap there in the first place?
Regards
L192

Hi L192
How much is the positive ripple across the 150uF cap? Is it a 100% ripple or less?

listener192 · June 02, 2018, 03:37:02 AM

Hi Jeg,

The relays failed before I could make any further measurements.
I only have a single bridge board at the moment but with that you can get consistant switching. If you run the clock at 10HZ you can see significant line ripple so I am optimistic about this approach. It will be a few weeks before I get the other bridge boards.

Regards

L192

Jeg · June 02, 2018, 04:29:48 AM

Quote from: listener192 on June 02, 2018, 03:37:02 AM
Hi Jeg,

The relays failed before I could make any further measurements.
I only have a single bridge board at the moment but with that you can get consistent switching. If you run the clock at 10HZ you can see significant line ripple so I am optimistic about this approach. It will be a few weeks before I get the other bridge boards.

First of all thanks for all your kind reports. I had already purchased my relay boards but after yours and Pierre's last failure reports i moved to Mosfets. Just finished my stator these days.

About this "Ripple" approach, i am also positive. But it will need a some kind of sync between switching and ripple's minimums/maximums.

listener192 · June 02, 2018, 06:57:55 AM

Hi Jeg,

The only hole in this theory is that the system still functions off the super caps, although this could just be less than OU as observed. Why have a frequency control at all? Perhaps it is really being used as a crude phase control when running the transformer from the line supply. When running looped the phase will be the same.

Regards

L192