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  1. daldesign

    eddy current bike light?

    btrueblood, I think you might be right. Yours is the best explanation I have heard. At first I thought they were capturing the tail of the eddy current time constant (as used for crack detection etc) but a simple experiment shot that down. I think the Reelight is a better design, which has PMs...
  2. daldesign

    eddy current bike light?

    A couple of guys in Holland or Germany created the Magnic Bike Light. http://urbanvelo.org/magnic-light/ I understand eddy currents, but am skeptical that the amount of power available is enough to drive the LED. They claim no moving parts other than the rim of the bike wheel.
  3. daldesign

    cross-polarization loss measurments

    Good day, VE1BLL. I am curious to know if the cross-pole pattern follows the horizontal pattern, at say 80 to 100 deg azimuth. If there is a null at 90 degrees in the co-polar pattern, is there a similar null in the cross-polar pattern? Some background: here in the US but not in Canada, one can...
  4. daldesign

    cross-polarization loss measurments

    We are trying to predict the cross-polarization pattern of 4-element and 6-element Yagi antennas at around 220MHz. The vendors have co-polar pattern data but not cross-polar patterns. Does anyone have any measured data on typical Yagis? The Yagis in question are mounted with elements horizontal...
  5. daldesign

    vfd power factor

    Thanks Jraef for the info on drive technology. We have enough problems right now, so I won't be starting a boost PFC or AFE anytime soon.
  6. daldesign

    vfd power factor

    Jraef, yes I am thinking about active PFC. But that adds around $50 to the system cost if we design it. While the US does not regulate PF yet, the new Smart Meters seem to have the potential to measure PF, both distortion and displacement. Right now we measure PF using a California Instruments...
  7. daldesign

    vfd power factor

    We design exercise equipment, some using DC drives and some using AC drives. They are in-house designs. The AC drive is a simple V/F type and exhibits poor PF (0.7 or less) owing to its front-end being a simple bridge rectifier and capacitor design. The supply is 240V 60Hz single-phase. The...
  8. daldesign

    radial lines

    I need to create a drawing of an encoder wheel, ie one that has an even # of light and dark segments equally spaced around a circle. Is there a way in Visio 2007? thanks
  9. daldesign

    Software recommendations for creating cable/harness drawings

    I have recently begun using AutoCAD for wiring harness schematics, but have a need for assembly drawings. AutoCAD does not seem to have this feature- is anyone aware of a way to use AutoCAD for this task? The new version for Electrical does not seem to have it either. Thanks

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