0
Electrical Troubleshooting
Electrical troubleshooting involves checking and resolving an electrical problem (such as when an electrical device stops working correctly). Common troubleshooting practices include checking if the power is on, the bulb has burnt out, or the breaker tripped.
885 Questions
What to do if the voltage is to high in your house?
It is very difficult to have residential voltage that is too high. Utility companies go to great lengths to keep voltages and frequency within very close tolerances. In the US residential voltage for lighting and outlets is a nominal 115 Volts, and normally doesn't vary more than 3 to 5 volts. That won't hurt anything. The other voltage present in residential buildings is 220 Volts. That voltage is used almost exclusively for electric dryers, water heaters, and electric ranges. It is used to provide large amounts of power and still keep the size of the electrical conductor reasonable. If you had to use 115 Volts you would draw twice the amps requiring a conductor capable of twice the capacity of a conductor destined for 115 Volt use. Those are more expensive and much harder to work with. DO NOT MIX THE TWO VOLTAGES! Plugging a 115 volt device in a 220 volt circuit will probably destroy the device. Plugging a 220 volt device in a 115 volt circuit will destroy the wiring if not properly protected, and may cause a fire. All wiring used in a residential setting is rated at 600 Volts. That means that the insulation will withstand 600 volts without breaking down. Therefore you can use the wire for any application in the house PROVIDED is is the proper size for the expected current. Fixtures (Switches, Outlets etc.) are rated by voltage and current. The rating is right on the device. You may have noticed that outlets have different blade patterns. That is to prevent plugging the wrong thing in an outlet. Since appliances are rated by voltage and current (amps), or voltage and power (watts) do not plug appliances in the wrong voltage or current. The appliance manufacturer has installed the proper plug for his appliance. You must use the properly configured outlet. Building inspectors insure that the residential circuits have the correct pattern devices on each circuit. If you must replace a device make sure that the black wire goes to the gold connector, silver goes to silver connector, and green goes to green. If you are really uncomfortable with your home wiring, hire a licensed electrician to verify that everything is correct. After that you can replace any device as long as you turn the device off first and then make sure you install the new device EXACTLY as the old one was installed.
How do you calculate no load current of motor?
On an average, the following assumptions will stand good for an induction motor: * Starting current (Ist) will be 5 times of the Full Load Amps (IFLA) * No Load Amps (INLA) can be any where between 0.3 to 0.5 times of IFLA; To the most, this figure depends upon the frame size of the motor; larger the frame size, smaller will be the INLA. This is also true for the wound rotor type induction motors. Manufacturers normally give two different current figures, one for the motor running with full load, and one for 'locked rotor'. Locked rotor current is the very high current drawn when power has been applied, but the motor has not had time to start spinning. <><><> No load current is important since this portion of the energy consumed will not be reflected in the process output, for a machine which is running continuously, no one can neglect whatever low value it is. Usually, the efficiencies will be mentioned and one can apply basic thumb rules to arrive no load current from those figures <><><> Manufacturers don't usually publish 'current at no load' for their motors. Since a motor with no load is not doing anything useful, no one really cares how much current is being drawn. It's kind of like putting your car up on a jack so the wheels are off the ground and asking how much fuel will the car burn sitting still with the wheels turning at 10 miles an hour - or at 100 miles per hour - who cares? !!!
What would cause beeping sound in wall socket?
A beeping sound in a wall socket could indicate a faulty electrical connection, a short circuit, or a wiring issue. It is important to disconnect any devices plugged into the socket and contact a qualified electrician to inspect and address the problem to prevent potential safety hazards.
Why do you need more than one type of voltage line in a house?
In the USA houses would have 120/240 volts. 120 volts at most receptacles and lights and 240 volts for larger equipment like your stove, dryer, hot water heater.
What causes electrical connections to explode?
Various flammable gasses, flammable liquids, and combustible dusts can ALL explode when mixed with sufficent air, and an electrical spark creates enough heat to ignite the mixture. Examples would include hydrogen, propane, gasoline, alcohol, powdered sugar and flour.
What is the difference between KVA and KW of a transformer?
Transformer power is given by P=V*I which takes the unit of KVA while that of KW has energy term which is not produced by the transformer.It only steps up or down the voltage.
Answer:
In a pure D.C. circuit, KW = KVA. However, in any A.C. circuit, there is real power {KW} and apparent power {KVA}, due to the voltage and current being out of phase. Power Factor is the ratio of KW to KVA. Transformers are rated in both KVA and PF. Multiplying the transformer KVA rating times the PF will yield KW.
<<>>
A transformer has separate ratings for maximum voltage and maximum current. Multiply the two together and that is called the VA rating, or kVA for larger transformers. So the transformer rating is independent of the power factor of the load.
Why do you use Two Winding run and start winding in the single phase motor?
Any transformer uses a minimum of two windings to change the voltage value. The primary side of the transformer is usually connected to the existing voltage. The secondary side of the transformer is usually connected to the load, who's voltage could be higher or lower voltage than the primary voltage.
If the secondary voltage is increased the transformer is known as a step up transformer and if the secondary voltage is decreased the transformer is known as a step down transformer.
The transformer terminal markings for the primary are H1 and H2 on a single coil primary and H1 to H4 on a dual voltage primary winding. Like wise the secondary terminal markings are X1 and X2 on a single coil secondary and X1 to X4 on a dual voltage secondary winding.
What is the difference between voltage series and current series feedback amplifier?
I assume a series of amplifiers with one F/B The F/B is the portion of voltage/current F/B from input to output no matter how many amplifiers are in series within the loop or what the gain of each one is.
How can you calculate busbar size?
Busbar Length x Busbar Size x 0.009
ex- Length= 12meter
Size = 60 X 10 mm
ie, 12 x 60 x 10 x 0.009
Ans = 65 kg
Can you please let us know what is "0.009" for???
Ans: 0.009 = copper density
Max. Current for 60 x 10mm = 60 x 10 x 1.55 = 930 AMP
What is "1.55" for??
How do you test an electric bell with a megger?
To better understand how to perform this test, it is important to understand what a megger test does.
A megger traditionally utilizes a relatively high voltage {500vdc} to detect minute leakage current in an insulator or conductor. These "pinhole" leaks lead to current arcing and eventually an electrical short to the frame of the device.
In the case of a bell, you would connect one lead to the metal frame of the bell and the other to either of the bell wires. The result of the test should be infinity or an open circuit.
Can a Dy11 vector group transformer be connected to a Yd1 vector group transformer source?
In series, yes. In parallel, nope!
Putting a Yd1 transformer in series with a Dy11 transformer would result in the output of the Dy11 transformer being identical to the input of the Yd1 transformer with the exception of the voltage magnitude - this will change depending on the winding ratio's on both transformers.
But, in regards to other properties of the voltage, the phases will in be in phase, with the voltage in-between the two transformers lagging by 30 degrees.
What are the Application of single phase induction motor?
Split-phase motors are used in many applications that require a medium amount of performance from a single phase source. Many of the motors used in homes that are supplied by single phase power are split-phase motors.
Some applications include running fans, blowers, water pumps, air compressors, conveyor belts, and more. The only limits on the applications that can use split-phase motors are the availability of single phase power and the charectoristics of the motor itself.
Why do you use resistors in computers?
Resistance: Electrical resistance describes how an electrical conductor (a wire) opposes the flow of an electrical current (flow of electrons). To overcome this opposition a voltage (a energy) must dropped (used) across the conductor (wire). Resistance can be described by ohms law: Ohms Law: R = V / I (Resistance = Voltage / Current) (resistance measured in ohms) where: Voltage [V]= the energy lost across an component (voltage measured in volts). Current [I] = the charge (electrons) flowing through an component (current measured in Amps). Electrical resistance can be thought of as sticking your hand out a car window. The faster [current] you drive the harder the wind presses [resistance] against you hand and therefore it takes more energy [voltage] to hold your hand steady. When trying to overcome electrical resistance, the electrical energy lost is turned into heat. This is how the elements of a household stove, toaster, and fan heater work. Because of the vacuum in a light bulb, the electrical energy lost is instead turned into light. It can be seen the electrical resistance plays a large role in modern life. Resistor: The resistor is the most common electronic component and is used to limit and/or control the voltage and current in an electronic circuit. Resistors are carefully manufactured to provide a predetermined value of electrical resistance which may range from 0.1 ohms to 100,000,000 ohms, depending on the application. The physical size of a resistor also varies dependant on the amount of power passing through the resistor, given by: P = V x I (Power = Voltage x Current) (power measured in watts) There are also many types of resistors including: · Variable Resistor - changes resistance when its shaft is rotated (volume knob on a stereo). · Thermistor - changes resistance when the temperature changes (used in a thermostat). · Light Dependant Resistor (LDR) - changes resistance when the lighting changes (used in children's night-lights). Resistor Example: An LED is a small red light (such as the one on the front of most TVs) and requires 2.0 volts and 0.02 amps to operate correctly. If we connected that LED up directly to a 12 volt battery, the voltage would be too high, and too much current would flow… the LED would blow up. We need to use a resistor to limit the voltage and current. But which value of resistance should the have resistor? Uses ohms law: R = V / I = (12.0 - 2.0) / 0.02 = 500 ohms (Note: the voltage across the resistor is the battery voltage minus the voltage we want across the LED) But which value of power should the resistor be capable of handling? P = V x I = (12.0 - 2.0) / 0.02 = 0.2 Watts
What is the difference between a galvanometer and an electric motor?
Well, both work on what is termed the 'motor principle', i.e. a current-carrying conductor, when placed in a magnetic field, is subject to a force perpendicular to that field. But that's where the similarity ends, for the operating coil in a galvanometer is restricted to move within an arc, whereas a motor's coil will continuously rotate.
How to check 220-240 volt single phase capacitor start motor if it will not start?
I'm assuming you want to check to see if the motor works.
In other words, if the motor isn't working you want to know if the motor is bad or the capacitor is bad.
Turn on power to the motor, and carefully attempt to start motor rotation in the correct direction by manually rotating the shaft or the load connected to the shaft.
If the motor will maintain its motion once you get it started, the problem is most likely a capacitor. Check the capacitors for bulging and replace any defective parts.
If the motor will not spin at all, or will not maintain any momentum, the motor is likely the problem. You can replace it or try to reduce the rotating friction by lubricating the bearings, etc.
IF YOU'RE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
If you do this work yourself, always turn off the powerat the breaker box/fuse panel BEFORE you attempt to do any work AND always use a meter or voltage indicator to insure the circuit is, in fact, de-energized.
How do you use a megger tester?
There are basically two types of meggers, an electronic one and the old-fashioned hand-cranked type. On the whole megger testing is non-destructive.
What happens is a DC voltage is applied to the device or winding under test. It is basically an insulation test to see if the insulation has been injured in any way to cause a short circuit when normal power is applied to it.
On some meggers there are 3 ranges 300V, 750V, and 1000 volts. Applying the proper voltage is essential to avoid damaging the device you are testing.
Working voltages up to 240 volts should use the 300 range. Working voltages up to 600 volts use the 750 volt range and working voltages above 600 use the 1000 volt range.
If you used the 1000 volt range on a device that had a working voltage of only say 24 volts, you could damage the insulation of the device just by testing it! So meggering a device is only non-destructive if you use the tester as its instructions tell you to.
<><><>
As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
Before you do any work yourself,
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
Why is the power off on on breaker when it is not flipped off?
Turning the breaker on allows the power to flow through to the outlets, lights, and appliances on that circuit, so yes power goes to and through a turned on breaker. If the breaker is off, but the main power is on, power still get to the breaker, usually from the bus bar that runs down the middle of the back of the breaker box.
How can burn three phase ac motor?
You need to ensure that each line conductor is correctly identified. If you replace them in the wrong sequence, then the new machine will run backwards when you energise it! It may be necessary to use a phase-sequence meter to confirm the phase-rotation before restoring supply to the new motor.
<><><>
As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
Before you do any work yourself,
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
What is theConstruction difference between stream turbine and gas turbine?
gas turbines and gas engines are different in mechanic designes uses diffrent liquid for engine we use flemmable gas we use for turbine liquide flemmable but they need air both gas turbines and gas engines are different in mechanic designes uses diffrent liquid for engine we use flemmable gas we use for turbine liquide flemmable but they need air both answer by nailiyoucef05@yahoo.fr
I dont think so. Gas engine works as the same principle of a petrol engine. And in gas turbine gas is burned and high velocity gas is passed through the turbine.
A gas engine is an internal combustion engine and have no turbines.
alamm2@asme.org
What is importance of a polarity test?
HERE'S AN EXAMPLE:
IF THE POLARITY IS BACKWARDS AT A LIGHT FIXTURE THEN THE HOT (120VOLTS) WILL BE THE OUTSIDE OF THE LIGHT BULB SCREW SHELL AND THE MIDDLE PRONG INSIDE THE SOCKET WILL BE THE NEUTRAL -- THEREFORE WHEN YOU CHANGE THE BURNT OUT LIGHT BULB YOU WILL GET SHOCKED BECAUSE THE SCREW SHELL PART IS HOT!! IF WIRED CORRECTLY YOU WILL NOT GET SHOCKED BECAUSE THE HOT (120VOLTS) WILL BE INSIDE THE SCREW SHELL ON THE PRONG AND YOU WON'T BE TOUCHING THAT PART WHEN YOU CHANGE THE LIGHT BULB!!
How many amps can a 14 AWG wire carry?
A wire is not like a bucket that holds amps but more like a pipe that lets the amperage flow through it. A # 14 wire is rated at 15 amps. Code only allows up to 80% for continuous use, 15 x .8 = 12 amps.
How does a megger or megohm meter work?
The same way as an OHM meter. You are measuring resistance in OHMs. However, this meter measures a higher scale of ohmage. It is used for checking insulation which should always have high ohmage (high resistance). The upper scale of high ohmage is marked on the meter as "infinity" or the Greek sysmbol for it.
What are the disadvantages of transmitting electric power at high voltage levels?
The main disadvantage is that high voltage causes surrounding air ionization and may cause negative health effects for people close by. However, electric losses will be less when electricity is transmitted at high voltage. The higher the voltage the less the electric losses.
Can a 380kva generator start a 335 HP motor on no load?
not you kan not start 22kw motor with 25kva generator (οχι)
How does the amount of load affect the efficiency of a transformer?
A transformer is a device in which two circuits are coupled by a magnetic field that is linked to both. There is no conductive connection between the circuits, which may be at arbitrary constant potentials. Only changes in one circuit affect the other. The circuits often carry at least approximately sinusoidal currents, and the effect of the transformer is to change the voltages, while transferring power with little loss. Sinusoidal excitation is not necessary, and transformers may handle arbitrary signals, in which the action can be considered as a transformation of impedances. The magnetic field coupling the circuits can be in air, but is usually in a ferromagnetic material, the core, in which the field can be thousands of times greater than it would be in air, making the transformer efficient and small. The transformer is an honorary electrical "machine" in which the flux changes occur by variation in currents with time, instead of by motion.
Most transformers with iron cores can be considered as ideal when you use them. An ideal transformer has no losses, an aim that is closely attained in practice, so the energy transfer from the primary circuit to the secondary circuit is perfect. The diagram represents such a transformer, showing the core with magnetic flux φ, the primary winding of N1 turns, and the secondary winding of N2 turns. The reference directions for the voltages and currents at the terminals are shown. All of these quantities are to be considered as phasor amplitudes, varying sinusoidally with time. Note the dots at one or the other of the terminals of each winding. Currents entering the dotted terminals produce flux in the same direction, the direction shown. The current and voltage ratios are equal to the turns ratio. This means that the power factor (cosine of the phase angle), and the power, are the same at input (primary) and output (secondary). These things you probably already know, and we will not explore their consequences further.
The diagram shows the usual schematic way to represent a transformer. In an actual transformer, the windings are wound on top of each other, not on separate legs, to reduce leakage flux. In the usual shell-type transformer, both primary and secondary are on one leg, and are surrounded by the core. A core-type transformer has windings covering the core legs.
In order to design a transformer, or to examine in more detail how it departs from ideality, it is necessary to understand how a transformer works, not just how to express its terminal relations in an approximate way. It is also important to know how the properties of the iron core affect the performance of the transformer. A real transformer becomes hot because of losses, and the ouput voltage may vary with load even when the primary voltage is held constant.
The mutual flux φ is the means of transfer of energy from primary to secondary, and links both windings. In an ideal transformer, this flux requires negligibly small ampere-turns to produce it, so the net ampere-turns, primary plus secondary, is about zero. When a current is drawn from the secondary in the positive direction, ampere-turns decrease substantially. This must be matched by an equal increase in primary ampere-turns, which is caused by an increase in the current entering the primary in the positive direction. In this way, the back-emf of the primary (the voltage induced in it by the flux φ) equals the voltage applied to the primary, as it must. This fundamental explanation of the operation of a transformer must be clearly understood before proceeding further.
