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Reduce current - reduce power.
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∙ 8y ago
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What motors is used in railway engines for traction?
dc series motor :A series-wound DC motor has a low resistance field and armature circuit. Because of this, when voltage is applied to it, the current is high. (Ohms Law: current = voltage/resistance). The advantage of high current is that the magnetic fields inside the motor are strong, producing high torque (turning force), so it is ideal for starting a train. The disadvantage is that the current flowing into the motor has to be limited, otherwise the supply could be overloaded and/or the motor and its cabling could be damaged.
High resistance in parallel connected with galvanometer to form voltmeter?
That won't work. To convert an ammeter (a galvanometer is a very sensitive type of ammeter) you connect a high value resistor in series with it.
Why should you be the internal resistance of the very few Amitr?
ammeter connect in series in circuit to measure the current, if the Ammeter have a high resistance it would effect the voltage value because there will be a drop voltage over the internal resistance of the Ammeter, so we desgin the ammeters with very low resistance...
How a current limit starter works for an electric motor?
it consists of a series of resistances, a magnet and a bar that is pulled by the magnet. Initially all the resistance comes in series so the current is limited. when the bar is pulled towards the magnet slowly the resistance decreases and the current increases. thus it protects the DC motor from initial high current.
For bulbs connected in series the high watt bulb has high resistance?
No, the highest wattage bulb will have the lowest resistance.
A galvanometer can be converted into a voltmeter by placing?
a high resistance in series
Why the series motor is started with some initial load?
In dc motors Speed is directly proportional to back emf and inversely proportional to flux i.e N∝(Eb/φ) In series motor back emf is practically constant. So if we start motor without any load Flux will be small and so speed will be very high. if we start motor without any load it will gain very high speed and may get damaged due to centrifugal forces. Series motor have very high starting torque and used where high starting torque is required.
Will a dc motor start if its field resistance is high?
Yes, it will still start.
Why ac motor has low power factor?
because of high resistance in the load.
Why no load-speed of a dc series motor is very high?
high torque
How galvanometer measure the exact voltage with series high resistor?
Assuming galvanometer has zero or negligible internal resistance. If u connect resistor R>>RL(Load resistance) and connect it parallel to RL, it will hardly cause any change in voltage across load resistance. Suppose small current Ig goes through galvanometer. Since galvanometer have zero internal resistance, Voltage across RL = Voltage across R = IgR
High repetition resistance training Innervates high threshold motor units?
Does not innervate high threshold motor units and limits the potential for Type IIB muscle fiber hyper
