21

For a large and/or high speed fan, there are several mechanical disadvantages, for example The outer ring is highly stressed and therefore heavy. It may also need a heavy containment system to avoid collateral damage if it breaks. For example in a large turbofan jet engine, a mechanical failure caused by a crack near the hub of the fan usually only releases ...


11

To add just a little to the answer from Mahendra Gunawardena, that device contains an electromagnetic coil and nearby a piece of iron that is connected to a valve mechanism. When electricity is sent to the coil, it becomes a magnet and draws the iron bit towards it. This opens the valve, and water can flow. A spring is furnished in the mechanism so that when ...


7

Relatively low lifting requirements (100 kg) Relatively fast lifting speed (80 fpm -> .4 m/s) The first part of your power calculation was wrong. There's no need to go into pulley diameters at this early stage of the calculation. Let's start at the load hook. 100 kg ~ 1 kN. Speed > 0.4 m/s. So power > 400 Watts. That's mechanical power, after a ...


7

The device in picture most likely is a monostable solenoid valve. A controller will command to open the valve for a specific duration. The design makes an assumption that there is sufficient water line pressure. The duration determines the amount of water or cleaning solution that is dispensed. Note: If the water line pressure drops, most modern day washing ...


7

Fans like the one on the right exist. These where first invented as rim-driven thrusters (rim driven is your search term, not centerless) for marine applications. The rim is the rotor of the electric motor driving the fans, the shroud around the rim contains the stator. With the amount of research I'm willing to do right now, I found no definitive statement ...


6

Some of this depends on how tough the dishes are. While taking a lot of room, I can see possibilitiles in a conveyer sorter. Concept one: Dishes are dumped onto a conveyer that is on a sideways slant. Operator initially only has to see that they are one layer deep. Use of multiple belts runing side by side at different speeds and textures may be able to ...


6

Figure 1. Silicone steel stamped lamination, stator and rotor. Image source:HS Magnets Figure 2. On their way to becoming motors.


5

I am thinking that one could use several car batteries connected in series as the power source and a cable from these batteries would be connected to a high voltage transformer which would provide the high voltage for the Jacob's Ladder. Since we're talking about a balloon, you need energy to heat the air, and that energy will be stored in something like a ...


5

This cannot be answered as is because almost all the critical information is missing. Mechanical Power required to move to the go kart is determined by the force and speed required Motor Power can converted from mechanical power and be put in terms of motor torque and motor RPM. Battery power can be converted from motor power and put in terms of voltage and ...


5

I recommend researching motor driver circuits. These motor drivers internal has a H-Bridge design and have both direct on of digital signal to manage both direction (forward, backwards) and stop. You will also need a micro controller to control the motor driver. Below is an example block diagram for you to visualize. Below are few good places to start ...


5

If I understand correctly, your question is "Why do we use a unit strain instead of something more meaningful like a percent strain?". The reason is that we are normalising with respect to a well-defined (and easily comprehensible) quantity. This is a very common theme in material science. If you look at the definition of the modulus of elasticity,...


4

Try the search term water proof or water resistance connectors for electric bikes. Here is similar Electric Bike Connector Here another similar connector used in Electric Bikes Here is similar connector from e-bay Looks like the supplier name is Higo Waterproof Connectors Also take a look at Korean Cable and Components. They are based in Germany. Another ...


4

You have two problems. First, the obvious, you have not taken the resistance of probes into account. Ohm's Law must be satisfied. Second, TP-60052 TWINTEX is a Dual Channel Power Supply only rated for 5A, 10A if you place channels in parallel. Impressive getting 7A from a 5A power supply. But it cannot supply your loads needs. This is probably why your ...


4

My understanding is that when you have a circuit with that's connect to a battery they has to be some resistor in the circuit of some kind to ensure the current on the wire is small enough to power the device (e.g a bulb). The bulb is the resistor! The power supply (battery) will provide the power the load requires subject to the battery's capability limits....


4

Those thin flaps allow the bronze bearing inside to tilt about slightly and thereby come into alignment with the axis of the fan shaft, thereby minimizing noise and friction. If the bearing as a whole is out of lubricant, then the bronze bearing will stick and can't shift into alignment and the device will be noisy and may also have difficulty spinning up to ...


4

I would like to answer this question slightly differently. The challenge with rechargeable batteries (Lithium Ion), each charge discharge cycle causes internal resistance of the battery to increase. This causes the usable life of the battery to decrease. Therefore if the rise internal resistance over time is decreased or fully resolved then the Lithium Ion ...


3

The Lagrangian for your 1D pitch system is $\mathcal{L} := T - U$, which is $$ \mathcal{L} = \frac{1}{2}(mb^2 + Ma^2)\dot{\phi}^2 + \frac{1}{2}J\dot{\theta}^2 + (Ma - mb)g\sin\phi $$ The Euler-Lagrange Equations are $$ \frac{d}{dt}\bigg(\frac{\partial\mathcal{L}}{\partial \dot{q}_k}\bigg) + \frac{\partial\mathcal{L}}{\partial q_k} = Q_k $$ This gives the ...


3

Depends on the load. If the load is the size of the single motor then that might be better, but if the load is half the full power rating often, then using one small one and bringing in the second as needed may be better. So you need to understand the load. A similar situation is often found for boilers where there is a leading and lagging boiler according ...


3

While DKNguyen's answer is accurate. I believe you're looking for a more holistic answer. Will it move? Absolutely it will move if you give it enough gear reduction. You could move the cart with a minuscule motor and a worm drive if you don't mind it creeping along. So the question is, how fast will it go? Or more accurately, how hard can it accelerate? and ...


3

Looking at photos of the battery used in your headphones, I believe they use one of two ways to do this: 1- The cells are parallel in orientation, leading me to believe they are electrically parallel. The IC could be matching them somehow, or perhaps the voltage is slightly different, as the eneloops are low discharge cells. the second, more likely scenario: ...


3

Based on the information shared and available there mostly three more possibilities. There is a make break switch that is triggered based on the battery packaging. Review the original battery package as well as the housing compartment for specific mechanical features associated with a trigger. Below are some battery packs that are similar to original. The ...


3

Different electric assist bikes will present different circumstances. For instance, a standard hub motor (front or rear wheel) will have permanent magnets which react with the iron in the stator. You can feel what is called cogging when rotating the wheel by hand, without power. This is energy expended by hand, but also applies when pedaling without applying ...


3

The actuator is rated for 500mA, but note that if it is electromagnetic, the transient inrush current at turn-on can be several times as big as that for a period of tens to hundreds of milliseconds. During that time, your wallwart voltage may sag down as it struggles to deliver the large current transient and if that happens, then the rest of the circuit may ...


3

Example 1: Hardware Integration Some organization have Electrical Hardware building blocks that have been pre-designed, tested and validated. These building blocks could be for step-down regulator circuits, microcontroller controller circuits, audio processing circuits, video processing circuits, AM/FM RF circuits, BLE circuits, etc. In order to design a ...


3

Could you get it to work, sure. There are dozens of ways to turn heat into energy. Could you get it to work at scale and cost effectively? Almost certainly not. There's just not enough energy in heated air to do much, and the capital costs of the system break the effort. This is another entry into the "Why can't Stirling engines give us almost free ...


2

For whatever reason standards bodies seem to prefer to give a tabulated list of values without giving any rationale to how those figures were obtained. I once tried to do some first-principles reasoning on this. Let $S$ be the surface area per unit length of the cable, $R$ be the resistance per unit length of the cable, $P$ be the power that can be safely ...


2

There are tables by various standards authorities which give current ratings for various wire gauges based on their insulation, bundling, free-air, conduit, etc. If you find one of those and plot the data you can generate your own best-fit curve. You might be able to get it down to a quadratic equation for a certain range of wire sizes.


2

Figure 1. Extract from Energiser E91 datasheet. The datasheet shows that at 100 mA you'll get about 2500 mAh (2.5 Ah) if you discharge to 0.8 V (and it doesn't get hot). Let's say that the average voltage is 1.25 V and we get the total useful energy is about 2.5 × 1.25 = 3.125 Wh = 3.125 × 3600 = 11250 Ws or 11250 J. Your calculation is the ...


2

This may be for a couple of reasons. The battery voltage will sag during high current draw, if the cutoff is too high it might trip even though the battery has plenty of capacity remaining. It may be there as a last resort, and set as low as possible so you can get all the power out of your battery if you want to. 3v per cell isn't great for longevity, but ...


2

You will have to change the magnetron and change the capacitor for a higher capacitance. Most lower wattage microwaves have lower capacitance capacitors. Or you can ditch the Microwave oven transformer and capacitor idea together. You can replace it with a panasonic DC to AC high voltage Power Converter. Those are more efficient and are usually higher ...


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