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1500 questions
4
votes
1 answer
Fan Sensors (Tachometer vs Locked Rotor)
With regard to Fan Sensors, there are two very common methods for detecting whether the fan is doing what it's supposed to or not.
Locked Rotor- Detects when the fan is working, or when it has stopped.
(on or off voltage signal)
Tachometer- Detects…
Erathsmus
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4
votes
1 answer
Perfectly aerodynamic kitchen range hood
Short form: How would one calculate the perfect shape of a range hood?
See drawing below. Will the curve of the profile of the range hood be exponential? Quadratic? What if the range is enclosed from three sides that create a box open only from the…
cheater
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4
votes
3 answers
What could be the reason for these sections not agreeing?
I have two results that don't seem to match up and I can't figure out why.
I built a hollow square section (HSS) using two different structural analysis softwares (they both agreed). However, they don't seem to agree with the AISC steel table…
carigs89
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4
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Why do we need to condense steam in the rankine cycle?
In my admittedly naive understanding of the rankine cycle, steam is condensed back into water after passing through the turbine. Why not reuse the steam instead? It would seem to require less effort to reuse heated steam than to intentionally…
Paul
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4
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2 answers
How can a planetary gearset "work" with gears whose pitch diameters are not tangent?
Somewhat new to the gear-world here, so I am trying to understand something. Most of the literature an examples of planetary gearsets that I've seen so far have described a relationship where the pitch circle of the planet gear(s) is tangent to both…
tectactoe
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4
votes
2 answers
Multi-position bi-stable solenoids in a small form factor
I am looking for multi-position bi-stable solenoids. So far, I have only found one vendor1 with a 3 position bi-stable solenoid.
Are there multi-position bi-stable solenoids with more than three positions? How can a 3 position bi-stable solenoid…
Mahendra Gunawardena
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4
votes
2 answers
Why do we need continuum approximation in fluid mechanics?
We know that a fluid in reality is not continuous. It has spaces and voids between atoms and molecules.
Continuum approximation is a famous approximation that is taken in any fluid mechanics textbook. It says that even though the fluid has spaces…
Harshit Rajput
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4
votes
4 answers
Direction of fluid flow
Consider water flowing in a pipe, and I don't know the direction of flow. How to determine the direction of flow?
My approach-
I can use a pitot tube but for that I have to drill a hole in the pipe and I can't use this approach for fluids whose…
MechaTrex
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4
votes
3 answers
What is the maximum possible compression with fuel injection in a gasoline combustion engine?
Maximum possible compression in a gasoline engine was originally determined by knocking in engines with carburetor. With fuel injection the fuel could be injected after compression and thus eliminate knocking. How high compression does fuel…
David Jonsson
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4
votes
1 answer
Tankless air compressor for electronics desoldering station
I purchased a Weller WSD161V soldering station (similar to this one, at least with regards to the pneumatic system I'm about to describe -- sorry, I was unable to find a manual for my specific model on the internet) with a DSX80 desoldering…
swineone
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4
votes
0 answers
Maximum Slope of Truck Parking Lot
What is the maximum grade/gradient allowed for non-temporary (overnight or longer) parking/vehicle storage areas in parking lots for heavy-duty vehicles such as semi-trucks and buses?
All I could find is that the International Building Code allows a…
4
votes
7 answers
Why can't trains stop in 2x the distance of trucks from the same speed?
I recently learned that every axle on a modern train has brakes. In the past, I had assumed that only locomotives and cabooses had brakes, and assumed that was the reason for the commonly known long stopping distance of trains.
This new discovery…
Azendale
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4
votes
2 answers
Cooling system to maintain 0.5 °C at 95% humidity
I am looking for some guidance on a redneck cooling system.
I need to store seeding trees at a temperature just above freezing, and at a humidity of close to saturation.
I only need the system for about 2 months of the year.
At present I use…
Sherwood Botsford
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4
votes
2 answers
What happens to generated electricity if it is not used?
Let's take for example hydroelectricity produced at a dam and not consumed by any household or industry... Will the electricity need to be stored? What will happen if it is not stored? Does it flow like water and get wasted back to the earth? What…
Nagendra
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4
votes
1 answer
Best Practice for Tracking Vendor Firmware Rev
My employer has had me create a model of a vendor product (using OnShape) and make a simple drawing with some overall dimensions that we can hand to customers. However, they want to include the firmware revision of this product in the drawing. I'm…
Optimum
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