Recent content by tinkeringone

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    What is the drag coefficient of a windsock?

    Does anyone know what the drag coefficient of a windsock is?
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    Does visible light contain energy?

    I read that Infra red waves that are absorbed are emitted by objects. And that makes sense. But then I read that it apparently works differently in the visible light spectrum, i.e. the visible light colors we see are only those that that aren’t absorbed, i.e. they’re only the ones that are...
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    Air pressure difference between floor & ceiling

    I guess not, if the tube you're referring to is the hose going from the digital manometer to the ceiling. I assumed that pressure in the hose was the same as the air pressure at the ceiling where the open end of that hose is. Never had to do that just measuring static pressure, i.e. in an...
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    Air pressure difference between floor & ceiling

    Can't figure out how to get my digital manometers to read the pressure difference between the air near the floor vs. at the 8' high ceiling. It reads 0 IWC no matter how I do it. One of my instruments is a micromanometer (reads as low as .001 IWC pressure differential), and it reads 0 IWC...
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    Directionality of sound vs. frequency

    Why do low frequency sounds (like low bass notes) disperse omni-directionally, whereas high frequency sounds are much more directional? Also is there a formula that governs this?
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    How many turns on a 50:5 CT for proper current ratio?

    I forgot to mention that when I got the meter, and discovered that it gave me no amps reading - only a voltage reading, I found that the solder joint where one of the 2 CT secondary wires is soldered to the board was cracked. The wire would wiggle around the board when I moved it. So I...
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    How many turns on a 50:5 CT for proper current ratio?

    Holy cow, I can't believe I forgot to mention that when I unplugged the watt meter, and put my pocket screwdriver up to the core, the core attracted it. But just to make sure, I just now put the pocket screwdriver on several other metal objects and discovered that my pocket SCREWDRIVER is...
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    How many turns on a 50:5 CT for proper current ratio?

    Something seems bogus with this core. I have 9 turns of about #20 insulated wire wrapped around the bare core with a 10 amp primary load (120V). I know for sure that the primary load is 10A, because my shop vac is the load, and I also measured the current in the primary wire with my Fluke...
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    How many turns on a 50:5 CT for proper current ratio?

    Thanks, Jim. I followed your advice, and dissected it, and saw a spot where the windings had arced across at least a couple of turns. As far as the number of turns go, it has 2 parallel wires wound around the core. I counted 19 wire turns around the core. And that's because one of the 2...
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    How many turns on a 50:5 CT for proper current ratio?

    Trying to resurrect an old, combination, analog volt/watt/amp meter. Traced the problem to a bad 50:5 current transformer (nothing coming out of the secondary taps with a 15 amp load going through the primary donut hole). I want to make sure there are no other problems with this unit before...
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    Electrical resistance of flattened (smashed) wire?

    Can anyone tell me what happens to the electrical resistance of solid copper wire, i.e. #4 gauge, (about .21" in diameter) uninsulated solid copper wire when you flatten it, i.e. with a hammer? I'm going to insert that wire inside a piece 1 3/8" diameter copper pipe, and smash the pipe over...
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    How Does Room Temperature and Humidity Affect Water Evaporation Rates?

    HVAC man here, still tinkering with humidification. Trying to get a baseline on the rate of evaporation of undisturbed water in a full container in a room with a fixed RH & temperature and no air currents. It's a cool (unheated) very small, room in my basement with a door on it. The room has...
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    How do I calculate the friction coefficient for my pendulum using Excel?

    Bob – here’s the source of my information you requested. It’s a very interesting source. He’s loading up a simple pendulum with lots of mechanical friction to the point where the friction losses overwhelm the air drag losses, making it easier to calculate the friction loss coefficient. It...
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    How do I calculate the friction coefficient for my pendulum using Excel?

    Not sure, but apparently somebody threw some LOGS in my pendulum. HELP! Trying to create a spreadsheet for calculating the friction coefficients in the pendulums I've been making. Here's the problem I just can't figure out. μβ = ln (1+Z) − ln (1−Z) where Z = Δθ(L/d) Δθ = 0.50...
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    Estimating humidifier evaporative capacities

    I'm an HVAC technician trying to assemble a spreadsheet with formulas for different furnace humidifiers to analyze the outputs of different models in different scenarios but the factors are horrendous. All would be of the same basic type "flow through", bypass air models. - Water flows through...
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