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Because the slip angle between magnetic fields decreases as the rotor comes up to speed.
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∙ 12y ago
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How star delta helping motor from overheat?
star delta motors start as a Y for 3 phase so the windings that normally see 480 volts see 277V a relay switches to delta then it runs as a normal delta motor the reduces the starting current by about 60% for 3 phase
What is the need for starters?
for protection from initial currents and short circuit,overload currentsFurther ExplanationWhen a motor is stationary, the only opposition to current flow is the resistance of its windings. When the motor starts to turn, it generates a back emf. So, on starting, the current is high, and it reduces in value as the machine runs up to speed. With larger motors the starting current could overheat and damage the windings, so it is necessary to restrict the value of the starting current using a 'starter'.
What is DC motor?
A DC motor is an electric motor that runs on direct current (DC) electricity. A DC motor is designed to run on DC electric power. Two examples of pure DC designs are Michael Faraday's homopolar motor (which is uncommon), and the ball bearing motor, which is (so far) a novelty. By far the most common DC motor types are the brushed and brushless types, which use internal and external commutation respectively to reverse the current in the windings in synchronism with rotation.
Why motor is taking high current and getting trip?
It is overloaded. take the motor loose and see if it runs normally if its on a machine that used to work check bearings misalignment bent shafts
How much percentage of current takes motor runs at no load?
The FLA of a motor is the amperage that the motor operates at. So to answer the question, 100%.
Why a motor starts in star and runs in delta?
This configuration is used to reduce the starting current. Utility companies do not like large motor loads starting across the line. It dips the voltage level of the line. By reducing the starting current to a lower level also reduces the voltage dip in the supply lines.
What type of device runs on DC current?
dc motor
How star delta helping motor from overheat?
star delta motors start as a Y for 3 phase so the windings that normally see 480 volts see 277V a relay switches to delta then it runs as a normal delta motor the reduces the starting current by about 60% for 3 phase
When the electric current runs through the wire loop of a motor it makes a?
Circuit
What is the need for starters?
for protection from initial currents and short circuit,overload currentsFurther ExplanationWhen a motor is stationary, the only opposition to current flow is the resistance of its windings. When the motor starts to turn, it generates a back emf. So, on starting, the current is high, and it reduces in value as the machine runs up to speed. With larger motors the starting current could overheat and damage the windings, so it is necessary to restrict the value of the starting current using a 'starter'.
What is the Difference maximum unit current draw and nominal unit current draw?
Maximum current is defined by the rated KW of the device, say Motor. The motor may not run at its maximum rated capacity all the time. Nominal current is drawn when motor runs at nominal load.
Can no muffler hurt the motor?
it really depends on the motor specs but yes it can because the muffler not only reduces engine noise it also provides enough back pressure for your vehicle to runs more efficient
Why starting current of the motor is high when it is directly connected to supply voltage?
When a motor is stationary, it is not generating a back-mmf which would otherwise act to oppose the applied voltage and, thus, reduce the supply current. However, as the motor runs up to speed, it generates an increasing back-emf, and the supply current falls.
What is DC motor?
A DC motor is an electric motor that runs on direct current (DC) electricity. A DC motor is designed to run on DC electric power. Two examples of pure DC designs are Michael Faraday's homopolar motor (which is uncommon), and the ball bearing motor, which is (so far) a novelty. By far the most common DC motor types are the brushed and brushless types, which use internal and external commutation respectively to reverse the current in the windings in synchronism with rotation.
Can a motor act like an electric generator?
when the motor runs more than rated speed it produces leading current and results act as a generator. (or) the motor act as generator when it produces more back e.m.f
What factors are considered in the selection of dc machine?
The initial factors are the working voltage and power level required. These set the size of the machine. There are three types of dc machine depending on how the internal magnetic field is produced. A permanent magnet machine gives a constant excitation field and is preferred for smaller motors since no field winding is needed and the machine is therefore simpler. A shunt-wound machine has the field winding in parallel with the armature (the rotating part) and is the commonest type of dc machine. This is used for high-power motors or generators (they are the same thing) where the speed of operation is fairly constant. A series-wound machine has the field winding in series with the armature. This type is used in traction, to drive trams and trolley-buses. The torque produced by a dc machine is proportional to the field current and also to the armature current, so a series motor produces torque proportional to the square of the current. When starting, the motor draws a high current limited only by the resistance in circuit, so the torque is very high and suitable for starting the vehicle. A switched starting-resistor keeps the current within limits. A standard shunt-wound motor acts as a motor when a mechanical load is applied, but if the motor is driven faster than it rotates naturally without a load, then power flows back into the supply and it becomes a generator. A shunt-wound motor tends to behave as a capacitor because the starting current is high and it then reduces exponentially as the rotor gathers speed. If the supply is disconnected, the terminal voltage reduces exponentially as the speed runs down. In a capacitor the energy is stored in the electric field while in the dc machine it is in the kinetic energy of the rotor.
Does a jet have a Motor or an Engine?
It depends on what it runs on. A motor runs on electricity and an engine runs on fossil fuels. It depends on what it runs on. A motor runs on electricity and an engine runs on fossil fuels.
