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Old 02-05-2009, 09:02 AM   #10 (permalink)
Master EcoModder
Join Date: Jun 2008
Location: London, Ontario
Posts: 1,096

2k2Prot5 - '02 Mazda Protege5
90 day: 33.82 mpg (US)
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Okay, two things to keep in mind to keep this conversation on track:
1) i have installed a car stereo before and i am well aware of the marketting crap. If it is made in china, that 1000W rating is NOT 1000W. Also, the RMS value of the 1000W peak amp is not the same as its continuous output. If i recall correctly, RMS of a perfect sine wave is peak/root(3) - this is NOT the same as continuous RMS capacity. Lets leave those details out. I am not expecting to drive a full-sized car on a couple "Thump" brand amps.

2) I'm talking about using 3 amps to control a 3-phase AC motor! Maybe i've been searching wrong, but you can NOT find a 600 dollar 3-phase AC motor controller! They cost a LOT.

As for the AC control - i'm a computer engineer... that means i'm a huge geek. I can figure that stuff out. Besides, there are already plenty of application notes, and i have access to the IEEE database of research papers. To start with I wouldn't even develope an embedded system to control this (which is not that hard either) i would start by outputing a sine wave from a computer program through a 1-phase motor for proof of concept.

I measured the resistance of a fan that i have at home and it was 15ohm on the high setting... i also noticed 4 wires going from the knob to the motor - so that fan is not suitable for testing "as is" (ie, not ripped appart). I have 2 more fans in the house that i will check out.
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