23

The most prosaic reason why your cable doesn't work and is drawing too much current is that you connected he wrong pairs of pins and/or some of the the wires are shorted together. If that is not the case, there are two obvious problems: A USB cable that meets the specifications has two twisted pairs of connectors enclosed in an outer shield, not four wires ...


22

Even aside from the fact that no outer sheath and no shielding makes me cringe, there are a couple of big issues with your custom cable: The data lines (pins 2 and 3) need to be a twisted pair. Period. USB uses differential signaling, and at the frequencies involved, the signaling lines need to be a twisted pair so that they actually behave correctly. The ...


11

Beryllium oxide is a very good electrical insulator but at the same time the best non-metal (except diamond) thermal conductor. So to summarize. In general, good thermal conductivity is correlated with good electrical conductivity, but it is not a strict relationship. For example, there is the empirical Wiedemann-Franz law for metals which states that the ...


8

ICEs (internal combustion engines) take some time to ramp up their output torque. Various mechanical systems have to react before more mixture is injected into cylinders, and that then makes more pressure upon combustion. Think of a throttle-body engine as example. You push on the gas pedal, which opens the throttle valve more. That causes more air to ...


8

Works similarly in the US (compared to UK responses). Natural monopolies are allowed to exist for utilities as it wouldn't make sense to have 3 or 4 different sewer lines running to everyone's home. The distribution company that owns the grid may or may not produce electricity itself. But there is (usually) only one power line that connects to a user.


7

For metals, good electrical conductivity does indeed imply good thermal conductivity. This is known from the Wiedemann–Franz law, which gives the ratio between electronic contribution of thermal conductivity ($\lambda$) and electrical conductivity ($\sigma$) and is proportional to the temperature ($T$). $$\frac{\lambda}{\sigma} = LT $$ This gives the ...


6

The current generated by a conductor moving through a magnetic field is related to the length of the conductor and the magnetic field strength. A coil is simply a convenient way to get a longer length of conductor within a given space. The cross sectional area doesn't actually matter in terms of generating power except insofar as it determines the current ...


6

In the UK there are three different parts of the complete system: generation, transmission and distribution, and supply (sales) to customers. There are many companies that generate electricity, varying in size from national (and even international) companies down to small organizations that operate a few wind turbines at one location. There are two parts ...


5

I think the instant torque claim mostly applies to "off the line" acceleration. That is from a standstill and electric motor has 100% of its available torque available at 0 rpm (mostly). The tradeoff is the an electric motor is always going to see a drop in torque with speed. Generally when you compare wheel torque availability as a function of speed between ...


5

Unless they have hearing loss, young people tend to be able to hear a larger range of sound frequencies than older people, particularly higher frequencies: Some security companies recently began manufacturing machines designed to emit an annoying sound that prevents teenagers from loitering outside stores and shops. Teens are effectively driven away, but ...


5

If I am not mistaken, you can use an H-Bridge for that. If you are using an arduino for example, there are a few motor drivers like L298N which do exactly that job (control the direction and speed of a dc motor).


4

The sun is heating mode. When the room temperature reaches the set temperature, the air conditioner stops operating until the temperature falls below the set temperature and the starts operating again. When in heating mode, the air conditioner does not cool. This setting is used during cold weather periods, such as in winter. The snowflake is cooling mode. ...


4

Yes, but... There's not great data available on the Fokotek products, but in general switching HP sized motor loads with solid state relays is a fairly expensive proposition. Because the voltage and current values don't cross zero at the same time, motor loads (inductive loads) are harder to switch than resistive loads. 3HP is just on the cusp where SSRs ...


4

We really need more info on the batteries and type of connection. Will the connection be permanent? In that case soldering or welding are the best choices. If you're connecting to wire, you'll need good strain relief. Any repetitive motion at the solder joint / weld will cause failure eventually. In a vehicle the battery may have a tendency to jostle around....


4

New homes are inspected by local authorities to comply with local building requlations. As Mike says, give them a call. The National Electrical Code (NEC) are standardized guidelines for electrical construction created by the National Fire Protection Association (NFPA). The NEC are guidelines, not laws. The NEC is adopted into law by states and local ...


4

For the USB signal, you have to make a 90 Ohm characteristic impedance twisted pair. The characteristic impedance depends on the insulator and on the outer/core diameter ratio of the wires. Search online calculators on the net. A simple way to twist wires: connect the two wires making a long wire twist the wire using an electrical drill put the wires ...


3

Interesting problem. Let’s see, if we have a cylinder 12 inches in diameter and 8 feet high that would be (pi*(0.5f)^2*8f)*7.48 g/ft3=47 gallons per operation. At 3 GPM, that would be about 15 minutes to fill the cylinder all the way. If it were used to lift a 6780 pound weight, 8 feet up, that would be 8*6780 foot pounds of work, in 15 minutes. That ...


3

Static electricity is a major issue when handling or dealing with explosives. When blast holes are loaded with ANFO (ammonium nitrate fuel oil) as the main explosive, and a specific density of ANFO is required in the holes, the ANFO is blown into the holes via compressed air and a tube. For short holes drilled with hand held machines, the tube is made of ...


3

No, it's a characteristic that electric motors produce most, if not all, of their torque from zero rpm - which is why the electric cars are so good at getting off the line and how electric motors don't always need gearing to start heavy machinery - just lots of energy...


3

For pretty fundamental physical reasons any power generator is only a way of converting one sort of energy to another ie converting the energy you have available to the sort of energy that you want. For example : Chemical energy to mechanical power eg an internal combustion engine Mechanical power to electrical power eg a generator Chemical energy to ...


3

I had to draw electrical and hydraulic schematics in Microsoft Visio at a past job. I'm glad that is behind me because that software is barely good enough for making flow charts. I would never recommend anyone use it for engineering diagrams. There are expensive professional software programs that solve this problem much better, but if you are on a budget I ...


3

I'd call the blue part the transmitter housing. This usually contains electronics for sensor signal conversion, which converts the sensor (or probe) low level signal to a standard 4-20 mA signal. The sensor (probe) is the metallic cylinder. And the sensor head (containing the sensing element, membrane/coil) is usually located at the end surface of the ...


3

DC motors make fine generators. You can test them by connecting the shaft of the motor to the chuck of a variable-speed electric drill and connecting the motor wires to a load resistor; you then measure output current and voltage as functions of drill speed.


3

The reason for the humming noise is improper grounding. Audio signals are low voltage level AC signals (over simplified). An audio signal could be for example 1V, 1 KHz signal. When there is improper grounding, a low level noise signal example 10mV 50Hz can get coupled to the audio signal causing humming. (Values are made up) I would suggest installing ...


3

Ever since 1975 use of at least one GFCI outlet and preferably more is mandatory in bathrooms or anywhere where there is the likelihood of moisture being near the outlet by NEC (National Electric Code). If you have only one GFCI in any bathroom, all other outlets in that bathroom must be downstream to that GFCI and controlled by it. You can ask your local ...


3

The device is likely not getting the power it needs. Use a thicker wire to ensure the resistance is the same as the original. Don't make an induction coil with your cable. It also helps to use twisted pair - see some of the faster ethernet cables for reference. You twist the two ends of a corresponding signal to preserve integrity. Since an approximately ...


3

Sorry, but the answer is "don't." When you use cables greater than (or even close to) the max rated length for a given comms protocol, you are asking for glitches and failures to occur. Get the right cable for the job.


2

As alluded to in the other answers, a most notable exception is diamond. Diamond is an excellent thermal conductor. The thermal conductivity of natural diamond is around 22 W/(cm·K), which makes diamond five times better than copper at conducting heat. At the same time, the electrical resistivity of most diamonds is on the order of 10E11 to 10E18 Ω·m.


2

The choice of cable is down to the environment that the cable is working in. Designers will be looking at mechanical abuse - by accident or not, temperature, chemical hazards etc. So, taking your some of your examples: Computer power -assuming you mean desktop little movement ambient temperature low chemical hazard. Kettles / toasters - temperature risk, ...


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