# Tag Info

10

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

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

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 ...

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

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

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

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 ...

4

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 ...

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 ...

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

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

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 ...

2

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 ...

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, ...

2

I answered a similar question on SE Sustainable Living recently. Before anyone (including yourself) can answer your question you need to supply some more information. The first thing you need to find out & provide is, what is the heating value of the gas. In metric units this would be the mega joules (MJ) of heat that one cubic metre of gas produces. ...

2

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...

2

If you couple together two motors of unequal speed through a gear system which allows the faster motor to match speed with the slower one, then the rotating speed will equal that of the slower one and their torque outputs will add. If you couple them in a manner where their output speeds do not match, then the more powerful motor will drive the other one ...

2

1) You could if you wanted to, but it's probably not necessary. Drawing less than the rated power should not hurt it. 2) yes and yes.

2

Voltage and Current multiply to give power. 15kV times 60mA is the same as 60Volt times 15 Amps (=900 Watts) You would not expect that to be a tiny thing, would you? And that power is without transformation losses. Keep in mind that 900 watts a common size for an electric space heater. This is not trivial power you are dealing with.

2

They would accomodate them by adding the necessary amount of either capacitance or inductance to the transmission lines to cancel the reactance. Note that this is commonly done today in order to trim the impedance of a large generator to match that of a high-voltage transmission line. It is also done to cancel the reactive component of a large electrical ...

2

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.

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The tweezers that you are describing have what's known as a Static Dissipative coating. This coating is conductive, but it has a very high resistance. What this means is that they are able to dissipate any differential charge slowly/safely, without there being a very low impedance path to ground that might produce an arc. Put simply, the tweezers will not ...

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Yes! The logic gates from a RS485/422. Most likely the signal are level shifted. Below is an except form Low power RS-485/RS-422 transceiver ST485B, ST485C datasheet. Below is an another similar part. PROFIBUS Compliant 6kV VDE-Reinforced Isolated RS-485 Transceiver ISL32741E. The example circuit is converting signal 3.3V-5V and 5V-3.3V.

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