0
Electrical Engineering
Electrical engineering is a field of engineering that deals with the study and application of electricity, electronics and electromagnetism.
23,056 Questions
Foods do not contain electricity. However, certain fruits like potatoes and lemons can be used to create a simple battery when combined with other materials like copper and zinc. This is known as a vegetable battery, but it does not generate electricity from the food itself.
Air bubbles are pockets of air trapped within a liquid or solid material. They can form naturally during processes like boiling or fermentation, or can be intentionally introduced for various purposes such as in aerating liquids like water or in products like bubble wrap for cushioning.
A 'volt ampere' (not 'volt amp'!) is the unit for theapparent power of a load in an a.c. circuit. It is simply the product of the supply voltage and the load current.
What instrument can be used to measure dynamic Valve Clearance?
A feeler gauge is typically used to measure dynamic valve clearance in internal combustion engines. The gauge is inserted between the valve stem and the rocker arm to determine the correct clearance while the engine is running.
A quick lesson on three-phase a.c. terminology.
The three energised ('hot') conductors that connect the load to the supply are termed 'lines' or 'line conductors'. The fourth wire, if present, is called the 'neutral' or 'neutral conductor'.
Anything connected between individual lines, in a three-phase, three-wire, system, are called 'phases'; anything connected between a line and neutral, in a three-phase, four-wire system, are called 'phases'.
So the individual windings of a three-phase alternator or three-phase transformer are phases. The three individual impedances that make up a three-phase load are also phases. The wires that connect the supply to the load are lines.
Voltages measured between lines, and the currents through lines, are called 'line voltages' and 'line currents', respectively. Voltages measured across individual loads, and the currents through those loads, are called 'phase voltages' and 'phase currents', respectively.
(Ignore anyone who calls the conductors that join the supply to the load, 'phases'. This is quite common but completely wrong!)
You can put less resistance (more load) on the battery with larger wires, but if you exceed a particular current output for a given duration, you will overheat the battery. To safely increase current output, use two batteries connected in parallel.
Current carrying capacity of cable?
The current carrying capacity of a cable depends on factors such as its material, size, and insulation. It is typically rated in amperes (A) and indicates the maximum current that the cable can safely carry without overheating. Exceeding this rating can pose a fire hazard or damage the cable.
In a reactor where electrochemistry is being conducted and electron exchange is taking place, the ions around a given electrode will permit a rapid initial electron current. But what happens after a few moments and the initial "rush" to the electrode is over? It's the ability of ions to diffuse through the electrolyte and get next to the electrode to continue the reaction that will govern the rate at which it preceeds. That sets the limiting current. Limiting current is the current flowing "out" or "in" an electrode in a reactor after the reaction begins and ion mobility takes control of the rate or speed of the reaction.
3.0 or three
AnswerIt depends how they are connected.
In series, ther total resistance will be 220 ohms and, so, the current will be 120/220 = 0.545 A.
In parallel, ther total resistance will be 20 ohms and, so, the current will be 120/20 = 6 A.
What is the relationship between current voltage and resistance?
The first, and perhaps most important, relationship between current, voltage, and resistance is called Ohm's Law, discovered by Georg Simon Ohm and published in his 1827 paper, The Galvanic Circuit Investigated Mathematically. Ohm's principal discovery was that the amount of electric current through a metal conductor in a circuit is directly proportional to the voltage impressed across it, for any given temperature. Ohm expressed his discovery in the form of a simple equation, describing how voltage, current, and resistance interrelate:
E = IR
In this algebraic expression, voltage (E) is equal to current (I) multiplied by resistance (R). Using algebra techniques, we can manipulate this equation into two variations, solving for I and for R, respectively: I = E/R and R = E/I.
answer discovered that relation only after VOLTA establish the voltage relationship and AMPERE discovered the current relationship. and of course WATTS establish the power.521
R=V
Resistance
OHMS
oli
What would be the amperage draw of a single phase 1200 watt heater if voltage is 120?
To calculate the amperage draw, you can use the formula P = V x I, where P is the power in watts, V is the voltage in volts, and I is the current in amps. Given that the power is 1200 watts and voltage is 120 volts, you can rearrange the formula to solve for current. Therefore, I = P / V, so the amperage draw of the heater would be 10 amps.
Why is the transformer turns ratio test needed?
Turns ratio test is very important in order to find out that the transformer has the right ratio corresponding on its rated voltage in primary and secondary. For example, three phase transformer is subjected to turns ratio test when each phase has equal turns ratio then the transformer is balance.
The test is performed to ensure that overheating or overcurrent conditions have not shorted turns in the transformer windings, which would distort the desired output or input voltage. This test is particularly important for instrument transformers, i.e. CTs and PTs which are connected to protective relays. These relays are extremely sensitive, and operate on very small fluctuations in secondary voltage or current. Shorted turns in these transformers can lead to big problems if they cause the relay to operate abnormally, or not at all.
What is Semiconducting tape which are used in power cables?
Semiconducting tape is a material used in power cables to create a smooth transition between the insulation and the metallic shield. It helps to evenly distribute electric field stress along the cable, reducing the risk of electrical breakdown and ensuring efficient power transmission. This tape is typically made from a special compound that has semiconducting properties to enhance the overall performance and reliability of the cable.
A volt free contact is a set of contacts that uses a voltage source from another location. The contacts are used to tie two individual pieces of electrical equipment together so the action on one will cause the other piece of equipment to operate. It is just a new way of using the older terminology "dry contacts". An example of use is the diesel start contacts on an automatic transfer switch. When the transfer switch is in the utility (hydro) position the diesel start "dry contacts" located in the transfer switch are open. On a power failure the transfer switch disconnects from the utility and connects to the generator position. When the transfer switch moves to the generator connect side the "dry contacts" , or volt free contacts, in the transfer switch close. This allows a voltage from the generator control panel (usually 24 volts DC) to return to the start relay located in the generator control panel. This relay engages the starter and starts the diesel generator. On return of utility power the reverse action takes place and the volt free contacts return to their normal state of normally open.
What is a visible index system?
A visible index system is a method of organizing and categorizing information that is easily accessible and identifiable. It typically involves using tabs, colors, or symbols to visually mark sections within a larger document, binder, or filing system for quick reference. This system helps users locate specific information more efficiently.
Why the primary coil and the secondary coil of a physical transformer wrapped on each other?
Close approximation of the primary and secondary coils makes for an efficient transformer. It is the rise and fall of the magnetic field that surrounds the wire in the primary that induces a current to flow in the secondary. The closer the wire producing the magnetic field is to the conductor being cut by the magnetic field (induction) the better the secondary output.
600 volts
I'd like to point out that your question is asking for the secondary voltage, which is usually lower than the primary, where there are more windings on the secondary than primary - Thus your secondary is higher voltage than your primary. I would say the question should be worded differently so the primary has 500 windings, and the secondary has 100 windings.
How do you rewire a 220 volt motor to run as a 110 volt motor on a old Howell electric motor?
Determine which leads are run leads, and which are start leads, or which are a combination of both. Once determined the overall solution is to parallel the windings externally, where at a higher voltage 1 motor lead per line is used, 2 would used per line in parallel.
Leads marked 1 through 4 would be connected 1 to line, and 4 to line with 2 and 3 electrically connected and isolated as a series connection for the higher 220 single phase voltage.
Rewire or reconnecting if possible to 110 would then be connected motor lead 1 and 3 to one of the 110 volt lines and the remaining motor leads 2 and 4 to the other 110 volt line.
In some cases the parallel connection could be 1 and 2 to line, and 3 and 4 to line for 110 volts.
It makes no difference on an induction single phase motor which line from the 110 either hot or neutral is connected to either pair of motor leads.
What type of accessory device can be used to measure AC with a VOM without opening the circuit?
Electricians use a clamp or clamp-on ammeter to measure current. The handles are squeezed together and the "jaws" open up. The clamp is then slipped over the conductor and the handles are released. The "jaws" close around the conductor and the meter is then in a position to measure current in that conductor. When current flows in a conductor, the current generates a magnetic field around the conductor. And the clamp-on ammeter can "feel" the current and measure it, thus permitting an investigator to know how much current is flowing in that conductor. The clamp-on ammeter is a stand-alone meter, but can sometimes be the kind that is plugged into a digital multimeter (DMM). A link to the Wikipedia article on the clamp ammeter is provided.
Why the rating of lightning arrestor is less than its rated voltage eg for 400 kv system it is 360?
The MAXIMUM rated voltage is the voltage at which the electricity would arc across the insulators The usage voltage is lower than the rated voltage (usually somewhere around 80% The lightning arrestor voltage is in between. It will not pass current at the usage voltage, but will pass current when the voltage exceeds the arrestor threshhold
Why do you use three phase power?
Single phase power has a sine wave voltage that crosses zero before reversing its polarity. In the region near the zero-crossing there is not much power. At zero there is none at all. So single phase loads often need some trickery to deliver output in this area. Often it is just the inertia of the motor or appliance.
Three phase power is always delivering power on one of its phases, and is thus preferred for machines, motors and appliances that use lots of power.
If the application is large power, or small power with weight restrictions (like automobiles!) Three Phase is preferred. DC (Direct Current) is the next step up for smooth high-power devices but requires rectification, regulation and smoothing to be useful.
Another problem with DC is that, for efficient long distance transmission, it cannot be simply converted to much higher voltages than the voltage at which it was generated at the power station. Similarly DC cannot be transformed down to safer, much lower mains voltages for use by consumers.
AC (Alternating Current) is used for high power generation and distribution because it can easily be transformed, using transformers, to achieve very efficient power transmission over very long distances and can then be transformed down to low voltages for distribution to consumers.
Two phase, and higher multi-phases are also used but very rarely.
Another Answer
Because, for a given load, less volume of copper is required to supply that load, making a three-phase system roughly 75% the cost of a corresponding single-phase system.
peak voltage is the highest level of volts giving from an alternating current. for example, in the UK the mains supply to a house is 230RMS. 230 is the average (simplified so bear with me) volts you will get from the AC supply. but in reality the AC wave is switching between -320 and 320 volts. so 320 is the peak voltage. to find out the peak voltage of an alternating current you must multiply the RMS voltage by root2 or 0.707 (this only works when the AC signal is a sine wave)
Totally wrong! Multiply the RMS voltage by 0.707 to find the PEAK voltage? What? The RMS voltage is 230. This times 0.707 is 163 which is far from the peak. Also 0.707 is not the sq. root of 2. I hope people don't take these answers seriously.
Peak Voltage is roughly 1.41 times the RMS voltage. (1.41 being the square root of 2) So 230 RMS mains voltage has a peak value of roughly 325V, (1.41x230). The original poster has accidentally multiplied the RMS value by 1 over the square root of 2 (0.707) ... which is what you multiply the peak value by in order to calculate the RMS.
Is tarnishing a physical change?
chemical, e.g. if you have silver, and it tarnishes, the dark spots (the tarnished areas) are actually silver oxide. If it were a physical change, the silver would need to change states of matter. Into gas, liquid or plasma
When two electronic equipments are put one after the other. The input of the last device is the load resistance. Scroll down to related links and look at the first figure of "Calculator Voltage Bridging - Interconnection of Two Audio Units".
What is the relationshi between a motors service factor and amperage rating?
A motor's service factor is a multiplier applied to a motor's horsepower rating to indicate the level of overload it can handle. The motor's nameplate amperage rating indicates the maximum current it should draw under normal operating conditions. The service factor does not directly impact the amperage rating, but motors with a higher service factor may be capable of handling higher loads and thus draw more current.
