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    Overvolted the "Name that Motor" today

    Here's a few more details on predicting motor iife vs. voltage http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/16125/ExtendingElectricMotorLife.pdf It seems if you run your motor at 33C above design winding temp you'll get 10% of the rated lifetime. Since motor winding temp rise...
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    Need help

    You don't seem to have much compassion, but maybe there's more to it. People who subscribe to this belief http://www.amazon.com/Belief-Just-World-Fundamental-Delusion/dp/0306404958 tend to blame the victim. It's especially bad when judges have it.
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    USB microscopes - seeking suggestions

    According to this http://www.nextag.com/USB-microscope/stores-html and using Excel's average and quartile function on a sample of the first 7 prices tells me that the average price is $106 and 3/4ths of the prices are between $56 and $113. So to avoid a POS you probably need to spend more...
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    Ping charger getting warm

    With power off, check that the fan blades turn freely. I can't see a reason for conserving the elec. power into the charger, and a thermal switch costs money, so I'd say it's more likely than not that the fan should be running. If the case is warm, some components inside may be quite hot.
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    My new 48v 1200W mean well power supply

    They don't seem to tell you how much input current the 5v control supply needs to source to give you a linear control curve, input V vs. output V. I s'pose it's an oversight.
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    Controllers

    In general: How can they modify the RPM vs. Torque curve of the motor they drive? What can they not modify about the motor's performance? TIA.
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    Analytic Cycling: Forces on Rider

    This link is the mother of all calculators. . .and the Cardanic equation it mentions may have come in handy a few months ago when I needed to solve a cubic equation. Muchas gracias! As far as 'people power', it's ~35W for 16 hours [based on Calorie consumption] and almost anyone can do 1 hp for...
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    Overvolted the "Name that Motor" today

    Never built one. I'd estimate building, testing and debugging the first version of such a thing would probably take a morning, not including fetching the parts. Start with a very light drag and see if the numbers make sense as far as matching the rpm/torque curve of your motor. You could...
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    Overvolted the "Name that Motor" today

    Here's the classical picture for one...
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    Tyres And Rated Load Specs

    Somebody probably has posted on the 'Net a tech report on weight vs. tire life, possibly for this type of tire. It's probably related to the sidewall flexing which causes heat which causes failure. I'd be interested in whether increasing the weight by 10% decreases the life by 10% or whether...
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    Analytic Cycling: Forces on Rider

    Here's another take on this http://www.analyticcycling.com/ForcesPower_Page.html
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    Tyres And Rated Load Specs

    Is this for a reasonable service life (how many hours?) until blowout or until some minimum tread depth? And, "As a rule of thumb, tire life decreases 10 percent for every 10 percent it is under-inflated."
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    Engineer shares how to build an electric vehicle...

    ~2200 lbs with driver 18.7 kW at constant torque up to around 3000 rpm and then constant horsepower (hp) up to 6000 rpm. a single reduction of around 6.3:1 Knowing the drive wheel radius (usually around 11"), drag coefficient, and a few simple physics formulas one should be able to predict...
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    HELP to electrify a pedal Go Kart for my son

    So a five to eight mile range. Somewhere on this forum will be users' experiences of how many watt-hours/mile and watt-hours/mile per pound of vehicle weight they have achieved. With these samples you can judge the likely size of the batteries required, and the rest will follow. Air drag at 15...
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    How to govern slot car power

    I used incand. bulbs for this in series with the transformer primary. 100W was pretty much the same as no limiter at all and 25W gave significant slowing. But there was no electronics in the controller. The actual power dissipated in the bulbs in these instances is not easy to calculate. I...
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    Overvolted the "Name that Motor" today

    While the bike is upside down make a Prony Brake out of a coil spring and a caliper brake to get some idea or get the RPM/torque or RPM/hp curves for the motor. If you have one curve you can determine the other from hp = TQxRPM/5252. Torque in lb-ft = Wheel radius in feet x coil spring pull in...
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    1.5Kw electric outboard design

    Since boat drag goes up steeply with boat speed I'd think you'd want a motor that has constant torque so the motor hp peaks at the highest RPM but I couldn't readily find a torque/speed curve for this motor.
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    Ampedbikes rear geared user experiences?

    The life of motor insulation halves for every 10C increase so in principle you could hook up a temperature sensor to a recorder/computer and see how much of the original motor design lifetime you have left, but you'd need the manufacturers input on what is the original motor design lifetime. The...
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    Any reason not to gang universal laptop chargers together?

    It might work with linear supplies. With switchers there will probably be unstable operation depending on how heavily the supplies are loaded.
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    thermometer with probe(s) that record Max temperature

    Silicon diodes can be used as temperature monitors, the voltage across them changes approx. -2.2 mV/degree C. Depending on the accuracy you want a monitoring peak/hold circuit can be built for a few dollars.
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    Choosing the value resistance of shunt.

    Try http://www.fairchildsemi.com/an/AN/AN-8201.pdf
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    car performance vs. hp required

    But another factor in doing conversions would be the rpm/torque curve of gas engines vs. elec motors vehicle cc hp rpm cc / hp   Top fuel dragster V8 supercharged 8194 8000+  8 200 1.0243 F1 racing car 1987 turbo - qualifying 1494 1400+ 14 000 1.0671 F1 racing car 1987 turbo - race trim - Honda...
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