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It is more efficient to transmit DC using about the same infrastructure. This is because of several effects: Skin effect experienced with AC. There is no skin effect with DC. Higher voltage allowed with DC for the same transmission lines. The lines have to withstand the peak voltage. With AC, that is 1.4 times higher than the RMS. With DC, the RMS and ...


40

I actually worked on HVDC schemes, back in the mid-to-late 90s. Olin Lathrop's answer is partially right, but not quite. I'll try not to repeat too much of his answer, but I'll clear up a few things. The losses for AC primarily come down to the inductance of the cable. This creates reactance for AC power transmission. A common misconception (repeated by ...


6

They're talking about complexity and costing (\$\$\$\$\$) The people saying "DC is less efficient" are using the word "efficiency" to talk about design factors like complexity of conversion hardware, and more critically, its cost. If we have a Santa Claus machine that can pop out DC/DC converters as cheap and reliable as comparable transformers, then DC ...


5

The math doesn't make any engineering sense. A 5MW turbine typically rotates at about 10 RPM, near enough 1 radian per second. Assuming you had reasonably big sprockets on the chain drive, say 2 meters diameter (!!) the linear speed of the chain would be 1 meter /second, and the tension in the chain would be about 5MN or about 500 tons force. Something ...


5

Trains do sometimes use different means for propulsion: Rack railways use cogs, and Funiculars use ropes I think the reason these are uncommon is that the available traction of smooth tracks is more than sufficient for all but really steep slopes (>10% ). Train engines may be limited in both torque and power when it comes to moving a heavy train up a steep ...


4

Because it is not a power cable (Q1) using power connectors (Q2). BNC cable has a solid conductor and a ground braid to electrically shield and mechanically protect the conductor. Electrical reason: Some ground braids are made of steel, which is not as good a conductor as copper, so voltage losses to the wire would be higher than copper wire. Basically, ...


3

Here you go: https://uk.rs-online.com/web/p/spur-gears/8787907/ The trouble is that a 1MOD 12 Tooth gear has a pitch diameter of 12mm, i.e.the bottom of the teeth is less than 12mm, so once you drill a 6mm hole through the middle there's really not much material left at all to make a hub from. What is the specific requirement or constraint that means you ...


3

This is more of an addition to the previous answer by blacksmith37. I think it might be more appropriate as a comment, or perhaps an edit to the previous answer. With no ability to comment at this time, I'll leave the next step to people smarter than myself. I believe this is a fairly straightforward answer: How they predict the amount to generate How ...


2

I think this question is about additional cross bracing. With a rectangular frame in a vertical plane the ability to carry compressive loads is excellent, but a comparatively small lateral force can deform the rectangle into a parallelogram which will collapse under the same loading. Since the cross bracing will operate to restrict primarily tensile and (to ...


2

a shock load on gearing is imposed when the gear train is forced to start or stop turning very suddenly, or when a heavy load is suddenly applied to a set of rotating gears. A good example of this is when the driver of a car with a manual transmission slams or "bangs" the gear changes without skilled use of the clutch, causing the car to suddenly lurch. This ...


2

With the high voltage AC power lines, there are trade offs between losses due to resistance in the wires, where the higher voltages are better and losses due to capacitance to the air, etc. where lower voltages are better. That is why many big, high voltage power transmission is done with DC these days. For example, the 500 kVDC line from the Intermountain ...


2

What are the respective tolerances on the “6mm”? Either it will be a press fit which will be sufficient to handle the torque and shock loading or it will not. If not, then you have to fit set screws and even machine a flat on the shaft.


2

Boston Gear or McMaster-Carr might have suitable off the shelf gears. You could also press the gear onto a hub that has a set screw. I would avoid pressing anything directly onto a motor shaft, you could bend the rotor and/or damage the internal bearings.


2

The transmission ratio is related to the number of teeth on the worm gear, and the number of starts on the worm. In your case, $$i=\frac{z_{worm\ gear}}{z_{worm}}=\frac{25}{1}=25$$. This means that you have a reduction of $25:1$, so, assuming $100\%$ efficiency, you would expect your output Torque to be 25 times higher than your input torque, and your ...


2

That might be overkill in your application (but I don't know). Figure 1. A random rigid flange coupling from an image search. A rigid flange coupling may be a more economic choice if it suits. From the comments: What are the benefits of a rigid flange compared to a split flange beside costs? Doesn't the flexible coupler give more friction? A flexible ...


2

you can use a pantograph belt. They use them in large machines to transfer rotation to a moving drill to cut squares and what not. Basically they are several pullies assembled on a pantograph with links designed to move as prescribed.


1

Your equation is correct for your definition of $d$. However, your definition of $d$ seems incorrect. $d$ is supposed to the be distance between the transmitter and the receiver, that is the distance on a straight line from the transmitter to the receiver. In your diagram you have (I think incorrectly) defined $d$ as the horizontal distance on some plane, ...


1

Ideal transformer - transformation ratio $$\alpha = \frac {V_1} {V_2} = \frac {N_1} {N_2} = \frac {I_2} {I_1}$$ Apparent Power: $$S_1 = S_2$$ Real transformer: $$\alpha = \frac {V_1} {V_2} = \frac {N_1} {N_2}$$ $$S_1 > S_2$$ The kVA rating on transformers deals with the output of the secondary side or $S_2$. There has to be a greater input power (and ...


1

The reason it turns about its center is the difference in rotation of the two wheels, which are connected through the sun-gears to planet-pinion gears. By rotating it allows the two sun-gears and consequently, the two wheels go at deferent speeds without either losing power, or having to skid. And the reason for the difference in the wheels speed is because ...


1

It is a spring-loaded ratchet and pawl system. the pawl mechanism is unlocked by the centripetal force of the initial rolling of the shade by a user. Here is a diagram.


1

A roller or inclined ramp clutch may be what you are talking about.


1

Ok, since nobody answered, I investigated this more on my own. Note: the answer is just an estimate and might have incorrect assumptions. In particular, I'm assuming 400 kV means 400 kV line-to-line voltage and not 400 kV line-to-neutral voltage, and I'm also assuming the voltages and amperages are RMS and not peak. These assumptions, if incorrect, change ...


1

You got good answers here, however, I think another little push is still needed. I suggest to examine the whole mechanism, end to end. Do you intend to drive the gate by a rack and pinion mechanism? First we need to estimate the force, speed and power needed to drive the gate. Let us conservatively assume a 0.1 friction coefficient between the gate and the ...


1

The gear ratio is the slope of worm gear per teeth of the round gear, so if one rotation of the worm gear turns two gears down on the round gear you have a ratio of $\frac{1}{(25/2)}= \frac{1}{12.5}.$ So you have to set this ratio according to the torque you need, same worm gear engaged to a round gear with more teeth is more torque, less speed. You then ...


1

Basically it works like a lever with the force or weight arm length as AC and resisting arm which is connected to the actuator as BC. The ratio of mechanical advantage remains constant as the jack lifts the load because the ratio of the horizontal projection of the arms which is proportional to their respective lengths multiplied by the cosine of angle ...


1

In gear design for different machinery there is a combination of loads that causes damage and excessive wear and the equation for that load: F* = Ka Kv Km Ft Ka is application factor inherent in connecting to moving parts. Kv is dynamic factor caused by imbalance and deficiency in gears. Km is load distribution factor on gear. Ft is service design ...


1

All else being equal DC transmission is more efficient than AC transmission at the same nominal voltage due to the elimination of reactive losses. However all else is rarely equal. At a given voltage DC is far more prone to sustaining arcs than AC. It is only relatively recently that we have developed the ability to convert between DC voltages with ...


1

If you imagine a square or rectangular shape made from rods joined with points at the corners. If those pins act as hinges then the whole shape can easily deform, effectively acting as a 4 bar link. On the other hand if the shape is a triangle then even if the corners are hinged then it can't be deformed without stretching one of the bars. Also, whichever ...


1

In answer to your questions: Yes, you can (and should) use a standard 5mm hub, such as the one shown in your question. The flat on the motor shaft is only there to provide somewhere for a grub screw to bite in (better than having a perfectly rounded shaft). No, I would stick with a standard hub with a circular hole, for the reasons stated above. I don't ...


1

If the system is not producing enough power voltage will drop so they know to produce more power. If voltage is too high then producers drop power. Distribution can bleed off power if required to not over power the consumer but the need for that is rare. In the US there is a grid west of the Mississippi and a grid and east of the Mississippi. There are ...


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