When the actuator is cold, a strong immidiate force appears after power up - without the capacitor beeing powered.
When it´s warmed up, this imidiate force is not there, just the slowly rising force like in the pictures. I can´t tell where this strong froce is coming from, maybe an inrush shock on powerup?
The funny thing is that it stays as long as the power is on. On power-down it releases quickly to the previous value.
The test setup for the Kocylator-Engine (Woodward thruster) is ready:
It is a balance scale, capable of measuring with a resolution of 0.0001 grams - theoretically. It´s oscillating around +/- 5mg, but the oscillation is slower than the immidiate forces I measured. The counterweight is a beer can, filled with scrap metal from the garage. The red box on the left side is used to fine tune the counterweight, because the scale can only handle 50 grams. I made first tests and measured 10 milligram-force ten times in a row. It´s repeatable and stable. However, I must test the source of the force. The force appears immidiately (pointing downward) after the power is switched on, but after a few seconds the force is going upward. When I switch off the cap-HV-oscillator and power only the actuator, the downward force disappears and only the upward force is clearly visible. It´s coming up slowly and decaying slowly after power down, so it´s most certainly coming from the actuator which is heating up. Further tests will include: Powering only the cap-HV and see if the immidiate downward force arises. If yes, it must be parasitic. If no, hurray. Then I´ll check the forces for different phase angles.
If the results show positive, I´ll ask for a test in Dresden in high vacuum and on a nanonewton sensitive scale.
Here are some graphs of the first tests.
The number seconds on the time axis has to be divided by 5 to get the correct time, because I increased the number of measuring points and didn´t apply the change to the time axis.
Here are the graphs. Where the indigo line goes bright, the power has been switched on. A downward force appears immediately, then an upward force slowly rises:
Here are the forces without the cap-HV. Clearly a temperature based force, slowly rising and decaying. This is most certainly the reason why the downward force only appears for a short time.
Here´s the overview of the hardware modules. It´s very straightforward and exchangeable. The inverter in version 1.0 was underdimensioned and got hot. The new inverter is doing the job much better. For the vacuum tests, I heatsinked the inverter mosfets directly to the chassis. There is also an additional heatsink thermally bonded to the inverter transformer core which will sink the heat to the chassis. Electrolytic caps are potted in epoxy to avoid eventual burst inside the vacuum chamber.
The #Kocylator engine is beeing improved: On the right side you see the new engine structure. It is an ultrasonic transducer with a resonant booster (embedded in the POM block). The booster increases the amplitude of the ultrasonic wave and also serves as mechannical support. The driving circuit has also been improved, because the power inverter was underdimensioned and got too hot. The new one doesn´t even get warm. There is a BNC connector on the driver board now which allows to monitor the current through the transducer. It´s resonating at about 37kHz.
Paul Kocyla
