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Electrical Engineering
Electrical engineering is a field of engineering that deals with the study and application of electricity, electronics and electromagnetism.
23,056 Questions
What is the use of 4-point starter in motors?
The four-point starter eliminates the drawback of the three-point starter. In addition to the same three points that were in use with the three-point starter, the other side of the line, L1, is the fourth point brought to the starter when the arm is moved from the "Off" position. The coil of the holding magnet is connected across the line. The holding magnet and starting resistors function identical as in the three-point starter. * The possibility of accidentally opening the field circuit is quite remote. The four-point starter provides the no-voltage protection to the motor. If the power fails, the motor is disconnected from the line.
How many leads are there in a capacitor?
Most caps I have seen have two leads. A basic cap has two leads in construction and in the circuit symbols. A composite cap may have more. It may have 4 leads on hi frequency inverters since the capacitance at very hi frequency becomes a coil of sort. Very expensive but very effective .
It sounds like you need a variable speed drill. There was an item on the market a few years ago that you could plug your drill into and control its speed. I haven't seen one lately since most new drills have variable speed built into the drill. On a drill press all you need to do is move the drive belt to the smallest pulley on the motor and the biggest pulley on the drill spindle.
Measuring the frequency of an alternating current using stationary waves?
Operation Tidal Wave was a strategic bombing mission executed by the American Air Forces in August 1943, during World War II intended to put nine Romanian oil refineries around Ploiesti "out of action."[5] The mission was unsuccessful in that it resulted in "no curtailment of overall product output"[7].
In terms of loss of life, this mission was one of the costliest for the United States Army Air Forces (USAAF) in the European Theatre, accounting for the loss of 53 aircraft and 660 aircrewmen. The day that it took place is known as "Black Sunday." Five Medals of Honor and numerous Distinguished Service Crosses were awarded to Operation Tidal Wave crew members.
Mission plan
For political reasons, the city of Ploiesti would not be bombed by accident.[5]
Colonel Jacob E. Smart devised the operation based on the experiences from the HALPRO raid. The 9th Air Force (98th and 376th Bombardment Groups) was responsible for the overall conduct of the raid, and the partially formed 8th Air Force provided three additional bomb groups (44th, 93rd, and 389th). The minimal air defenses encountered during the HALPRO raid contributed to the decision to use a daylight, low-level attack in order to counter the German radar coverage.[citation needed] Training included extensive review of detailed sand table models, practice raids over a mock-up of the target in the Libyan desert and practical exercises over a number of secondary targets in July to prove the viability of such a low level strike. The B-24 Liberators to be used were re-equipped with bomb bay fuel tanks to increase their fuel capacity to 3,100 gallons. The operation was to consist of 178 bombers with a total of 1,764 aircrewmen,[specify] being one of the largest commitments of American heavy bombers and crewmen up to that time. The route from airfields near Benghazi, Libya, was across the Mediterranean Sea and the Adriatic Sea, past the island of Corfu, over the Albanian Pindus Mountains, and across southern Yugoslavia. Following a series of pre-determined check points, the formation next turned toward Ploieşti and simultaneously struck their multiple targets from the north.
A current source is a source that we can draw current from and can regulate to control the amount of current we draw. It is kind of a "mirror" of the voltage source. Here's how it might work. We usually are interested in keeping the current constant when we use a current source (though not always). To do this takes a varying voltage source to keep that current constant when using the source with a dynamic load (a load that is changing). There will have to be a way for the source to sense current flow and compare it to the setting put in. That way the source can maintain that constant current by adjusting to the correct voltage needed to maintain it. Many battery charging applications require this technology. We want "maximum" current so we can quickly charge the battery, but we cannot "overload" the battery, so we have to be careful not to do that. A constant current source is the answer. It will supply a steady "maximum" current, and the source will (as the battery charges and the "resistance to more charge" increases) increase in voltage to keep that amount of current flowing into the battery to charge it in the shortest time. A VERY GOOD EXPLANATION and I could add that a perfect current source would have 0 (zero) input/output impedance or you could say it's would be more like "a short that provides power".
What is the function of Bypass diode in the test terminals of a pressure transmitter?
The function of the bypass diode is to allow the loop current to be measured without disconnecting the current loop connections. It therefore allows for a quick measurement of the loop current without disturbing any control or monitoring equipment that is connected to it.
This is achieved by simply connecting an ammeter across the diode. If the voltage drop across the ammeter is less than that of the diode (about 0.6V) then all of the loop current will flow through the ammeter rather than the diode. The ammeter is therefore able to measure the loop current.
What is an unpolarized capacitor?
A capacitor that does not have a designated + and - side. Electrolytic capacitors are usually polarized. Ceramic capacitors are not.
What is the difference between Base loads and peak loads in power system?
Base load is the level that it typically does not go below, that is, the basic amount of electricity that is always required.
Peak load is the daily fluctuation of electricity use. It is usually lowest in the wee hours of the morning and highest in the early evening. It also varies seasonally.
Are base and peak loads provided differently?Base load is typically provided by large coal-fired and nuclear power stations. They may take days to fire up, and their output does not vary.Peak load, the variable part of the electrical supply and demand, is provided by more responsive and smaller plants whose output can be quickly ramped up and down or that can even be quickly turned on and off.
The components are connected in series (not parallel).
Power lines and electronic equipment: 150m
Why should a JFET be operated with only reverse bias on the gate source?
What is the venin and norton equivalent circuit comment?
Read more: What_is_the_venin_and_norton_equivalent_circuit_comment
to disconnect the circuit when faults occurs
AnswerA 'disconnector switch' is another term for an 'isolating switch' or 'isolator'. It is a manually-operated switch used to provide a visible break between a de-energised part of a circuit and the energised part of a circuit so that work can be carried out safely on the de-energised part. A disconnector switch is not intended to break a load current, and most certainly not designed to break a fault current -that is the function of a circuit breaker.
Things to know about electrical engineer?
A good engineer is a person that knows which book to pick up read to get the answers. This is true especially in the electronic field. the branches of electronics is to say immense.
How do you load multiple cds in a 2003 Mercury Sable with factory 6 CD changer no manuals included?
press the "load" button. The CD player will ask you which slot? Use the number buttons to select a slot 1-6. It will move to that slot and open the door. Insert the CD, and then hit load again, and it will ask you which slot again. Repeat this process up to 6 CDs.
What is the difference between VT and PT transformer?
Both are same.
AnswerA 'PT' is a 'potential transformer', the preferred term in North America, for what is termed a 'VT', or 'voltage transformer', in Britain. Two names for exactly the same instrument transformer.
What is the result on the meter reading of clamping the jaws of a clamp-on ammeter around two wires?
If the two wires are on a parallel feed you would read the current through the parallel feeders. If the two wires are "hot " to the load and return back from the load the meter will read zero. The two magnetic fields that surround the wires when a current flows through them will cancel each other. As a result of this there will be no magnetic induction induced into the sensing coil of the clamp on meter.
Does diode flow current in reverse bias?
Diodes will have a small leakage current in reverse bias. In most cases, this current can be considered insignificant and ignored.
30MVA power transformer can uprated to what extend?
You need to discuss with a transformer manufacturer, because modifications will need to be made. The transformer name plate will say the top rating of the transformer (I'm assuming in this case it is 30MVA). This top rating is generally limitted by heating. So to uprate, you need to modify the cooling system - add more or bigger fans, add pumps, etc.
In my area, loading as high as 125% of max rating of transformers is allowed on a "short term" basis (in general), which gives system operators time to shift load without dropping customers.
If 30MVA is the base rating, I see typical values of 166% and 186% for ONAF1 and ONAF2 (oil natural, air forced level #1 and #2). This is something that is specified when ordering the transformer, so it may be different in your case (look at the nameplate!). The 30MVA base transformers I've seen, therefore are rated at 30/49.8/56MVA (at 65 degree C).
How component size decreases when frequency decreases?
The impedance of a component (inductor or capacitor) will change with frequency - resistor impedances will not.
Inductor impedance - j*w*L
Capacitor impedance - 1/(j*w*C)
L = inductance, C = capacitance, j = i = imaginary number, w = frequency in radians
The actual inductance and capacitance does not change with frequency, only the impedance.
What are difference between ac and dc switch?
A.C means Alternating Current .. And D.C Means Direct Current .. you should know the Basics of Electronics else you would not get survive in future .. in A.C .. Current Travels in the Wave Form Type .. where as in the D.C .. Currents Travel in Direct Path .. A.C Current is generated by Transformer ... Turbines and way of other things .. but D.C Current is present around you in a single Cell .. in Battery ...
Most Famously Electronics Almost Based Upon D.C Circuits .
Beloved Star Wars character R2-D2 is not dead, he is very much alive as is the actor who voices him. This was a internet death hoax.
What are the signs of a worn your circuit breaker?
They don't wear out for the most part,just fail to work. If something seems wrong,it is most likely the wiring,switch,outlet,or component.
