Russell McMahon
  • Member for 6 years, 11 months
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What does "$\pm$ 0.5% F.S." mean?
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15 votes

FS = FULL SCALE = maximum reading. It means that the accuracy is such that the reading is probably within + or - 0.5% of the FULL SCALE reading. This is a very important and easily overlooked ...

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What's the purpose of these small closet-like-rooms-without-a-door?
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12 votes

I do not know, I've never been there and I have no other information other than what is in your question. However, ... I'd say that best guess, until somebody who knows more presents, is your ...

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Do magnetic fields applied to a fuel line have an effect on heat output?
11 votes

If you can replicate what you report above under controlled conditions then you can retire for life next year. Really. The overwhelming opinion by all reputable test houses or suitably competent ...

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What are the common failure points of waterproof cases?
10 votes

Summary: The design of genuinely waterproof containers is an arcane art but is reasonably doable if certain rules are adhered to which codify the underlying "magic". Failures occur when the basic ...

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How do you attach something temporary to a smooth metal shaft?
10 votes

A method which works extremely well and which does not require set screws and/or flats on the shaft and which can be added or removed easily and rapidly is a collet based connector. While any one of ...

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Could air-launched space planes reach escape velocities?
9 votes

Now, I wonder if an air-launched spacecraft in the next 20 years realistically could really fly us to the moon - that is, could they reach escape velocities? Air launch to LEO: Done now Air launch ...

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Can nuts safely be removed from bolts where the threads have been intentionally damaged?
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9 votes

I asked a friend who is a highly competent EE by day - but who restores super sized steam engines by night and collects olde heavy metal engines etc and has much experience with old large corroded ...

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Electromechanically open and close a small, hinged door?
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9 votes

Rod & Nut drive A threaded rod and captive nut, with either rod or nut driven rotationally by a motor is liable to offer a good solution. Because: Power level is set by thread pitch and ...

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Is interference between aircraft an issue for fly-by-wireless technology?
8 votes

Modern communications systems are able to achieve essentially any desired data rate and degree of message integrity in any well-enough-defined environment. It's "just a matter" of the degree of effort,...

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Mechanism of gear rotation
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8 votes

Two meshed gears are used to transfer rotational drive between two shafts. The relative speeds of rotation are inversely proportional to the number of teeth on each gear. That is - $$\text{Input}_{\...

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What is a tesla turbine and how is it different from other turbines(like pelton or francis turbine)?
7 votes

While "conventional turbines operate by imparting impulse or reaction energy from an incoming fluid using "buckets" or spiral surfaces on the turbine "runner", a "Tesla ...

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How does a multimeter protect itself from high voltages?
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7 votes

WARNING: Note that some cheap meters are not suitable for use with 230 VAC AC mains. Some meters may have AC voltage ranges able to conceptually measure to well above AC mains voltage BUT have ...

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How does one go about building an underground structure without concrete?
7 votes

General: The assumption that concrete was not available is probably correct but not certain. The Colosseum is largely concrete and the Pantheon (still) has the largest unreinforced concrete dome in ...

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Can I use a pipe of any material other than copper in a counter-flow heat exchanger?
7 votes

If your question means, "for a given surface area and wall thickness, is there anything that performs better than Copper", then the answer is - "Unless you are prepared to make your ...

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How can I turn home gas (LPG) from liquid to gas?
7 votes

Lighters usually use Butane. Gas bottles use some or all Propane. Propane pressures are MUCH higher. A plastic 'tank' filled with Propane would probably explode. As size increases the container ...

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Can large capacitors allow power plants to run at full load and store excess electricity?
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6 votes

Capacitors are currently "rather too costly" for this purpose. I've revised my estimated cost after some more research but you appear to be in the 'well over one hundred thousand dollars" range! ...

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How much current is this phone drawing?
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6 votes

This answer is based on extra information provided by the OP in the form of a photo. The claimed currents were far too low due ti a misunderstanding in how to read the meter's 10A range display. The ...

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Why does the microwave plate start in a random direction?
6 votes

Three types of motor may be used, both of which could do this. One of these (the Synchronous motor) is wat is used here and is a subset of the Brushless DC motor. (A misnomer as there is no pure DC ...

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What makes the material travel through Archimedes' Screw?
6 votes

This is effectively an addition to other answers: An original Archimedes screw for liquids does not work as most people imagine it does, and the diagram does NOT show how an original Archimedes screw ...

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Could future fusion energy exist without the input of any petroleum or natural gas products?
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5 votes

The energy cost of obtaining Deuterium and Lithium is minimal compared to the energy released by the fusion process. There are many references that provide relevant information but a sensible one to ...

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What would happen if we tried to run a motor in space when it is not attached to anything to provide support to it?
Accepted answer
5 votes

Initially Assume an ideal motor with no mechanical losses and Operation in a perfect vacuum. Call the two portions rotor and stator - with all attached parts such as controller and power pack ...

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What is meant by the terms "low pass sensor" and "band pass sensor" in a course syllabus?
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5 votes

You are combining two concepts. A sensor is any device that responds to a desired signal in some manner to produce an output that is used to detect the presence of the desired signal or to allow ...

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What stainless steels are good for induction heating?
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5 votes

... that article only lists the surface resistance for 430 & 432 stainless steel -- the better being 432. However, I cannot find 432 from my favorite supplier, although they do have 430. Will 430 ...

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How to generate a synthetic infrared and red LED signal for SPO2 calculation
Accepted answer
5 votes

Short: (1.) Mindless and without understanding method that would work well. This is as quick and easy as is likely to be possible, should work 'well enough' and would be 'easy enough' to implement ...

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What is the "10/100/1000 BASE-T" laser/transceiver rate unit signifying?
Accepted answer
5 votes

The 10/100/1000 refers to the transmission rate in megabits per second = millions of bits per second. Also may be shown as Mbps or Mb/s. 1000 Mb/s is a data rate typically achieved by modern LAN ...

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Why raised face for mating parts?
5 votes

Surfaces on a two part mated assembly that is required to provide sealing must be designed so that the seal acts as a seal. While that sounds obvious, it seems to have escaped too many designers and ...

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How do I calculate the gear ratio to lift a weight at a constant speed?
Accepted answer
5 votes

I have a 80gcm motor with a rpm of 15000. I want to lift a weight of 2 kg at a speed of 0.5 m/s. How do I go about calculating the gear ratio required for this? Firstly - is it possible? In ...

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What concerns would I need to consider for building a swimming pool of gold coins?
5 votes

"Swimming" would be about impossible. IF the gold conveyed buoyancy as water does, which it wouldn't, - at full density you'd "float" with about 5% immersed. If mean density due to packing was about ...

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Why design a cable stayed bridge with pylons inclined towards the obstacle being spanned?
4 votes

As AndyT says - it seems it's aesthetics in most cases. Given the above as the answer, the following is essentially comment, but seemed worth posting as it gives a lot of detail of what goes into a ...

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If my electronics are outdoors in a ventillated NEMA 4 enclosure, should I conformal coat my circuit boards?
4 votes

Requirements depend on environment,but, yes, conformal coating is, at a minimum, a really really good idea. Apart from condensation and misc stuff that manages to get in, ants can wreak havoc, ...

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