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Loops of wire that turn in the magnetic field of an armature create current?
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∙ 14y ago
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∙ 14y ago
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What is the current in the secondary coil fi the current in the primary coil is 5.0A 10 loops on primary coil and 20 on secondary coil?
If I am not wrong then you have asked about a transformer. And its a current transformer. By theory of voltage transformer we know that Vs/Vp = Ns/Np So for answering your question we need the value of number of turns in primary and secondary coil. But you can use this equation to find your answer if you have other values. By using ohmic law you can convert voltage to current.
What is motoring mode of DC motor?
Read this Part I:DC Motor principles pg 1 Part I: Principles of DC Drive Control Learning Objectives: * to learn the basic characteristics of DC motors and their control parameters * to understand the various operating modes DCmotors and their representation: The basic principle of a DCmotor is the production of a torque as a result of the flux interaction between a "field" produced on the STATOR (either produced by a permanent magnet, or a field winding) and the current circulating in the "armature" windings on the ROTOR. In order to produce a torque of constant sign, the armature winding loops are connected to a set of "brushes" which commutate the current appropriately in each loop according to their geometric position. The commutator is a MECHANICAL RECTIFIER. Note that reversal of either the field current or the armature current results in a torque in the opposite direction. However, reversal of both fields does not change the torque direction, hence it can be used as a "universal motor" with DC or AC feed if both windings are in series. Basic Equations of a DC Machine: Steady state conditions (assume all time varying quantities have a constant average value) ( ) ( ) ( ) ( ) ( ) P T developed power T K I I A B T electrical torque V R I E R I K I armature voltage E K I Counter emf or Back EMF V R I fieldwinding d e e t f a load a a a a a v f v f f f f w w w w = = = + + = + = + = = (The back emf assumes that the magnetizing characteristic, E(If) is linear) Speed control: we can extract: v f a a a K I V - R I w = and one can control the speed with 1) Va "Voltage Control" 2) If "Field Control" 3) Ia (with If fixed) "Demand Torque" In practice, for speeds less than the base speed (rated), the armature current and field currents aremaintained at fixed values (hence constant torque operation), and the armature voltage controls the speed. For speeds higher than the base speed, the armature voltage is maintained at rated value, and the field current is varied to control the speed (note the hyperbolic characteristic). However, N +V (free wheeling diode) Armature Current (Rf, Lf) (La, Ra) Eo Rfc Field Control Resistor Fig 1: DC Motor Part I:DC Motor principles pg 2 this way the power developed Pd is maintained constant. This mode is referred to as "field weakening" operation. Case of Series Motor (or Universal Motor) In this case the field winding is series with the armature winding, hence If and Ia are equal. This leads to: v a a a f a K I V - (R + R )I w = One can either control the armature voltage (Voltage Control), or the armature current (Current Control) which is a measure of the torque control. Td , Pd Torque Power constant torque constant power speed Ia If Fig 2: Control Modes Torque Power constant torque constant power speed Td Ia Fig 3: DC Series Motor Control Part I:DC Motor principles pg 3 OperatingModes of DCMotors: Motoring: The back emf E < Va both Ia and If are positive. The motor develops a torque to meet the load torque. Dynamic Breaking: The voltage source is removed, and the armature is shorted. The kinetic energy stored in the rotor of the motor is dissipated in the armature resistance since the machine now works as a generator. Note here that theoretically, since the armature voltage is proportional to the speed, the motor would never stop... but in fact because there is also friction and viscous friction (windage), the motor will stop as soon as the speed is at a certain low value. Regenerative Breaking: The back emf E > Va , the machine acts as a generator, and the armature current flows towards the source, hence energy stored in the machine rotor is fed back to the source. Note however that this will cause the machine to slow down usually until E=Va and then revert to mode 1. Plugging: Plugging iswhen the field current is reversed, hence the back emf changes sign, and the equation of the machine becomes: a a a V = -E - R I hence a a a R I V E + = which means a very high torque generated in the opposite direction of rotation. Avery powerful breaking takes place. However it must be noted that the armature has to be opened as soon as the motor reaches zero speed, otherwise it will start rotating in the opposite direction. N +Va Rfc (La, Ra) E Ia (Rf, Lf) +Vf If Fig 4: Motoring Forward Tem w rated torque V1 V2 V3 V2 Tload FIG 5 torque speed V2 N +Va Rfc (La, Ra) E (Rf, Lf) +Vf Fig 6: Dynamic Breaking + Ia R V2 N +Va Rfc (La, Ra) E (Rf, Lf) +Vf Fig 7: Regenerative Breaking + Ia Part I:DC Motor principles pg 4 Two Transistor control of regenerative operation When the main switch opens, the armature current I(a1) has to be dissipated through the freewheeling diode. Then if one closes switch T1, the machine behaves as a generator with the energy stored in its inertia. Therefore the armature current I(a2)will start flowing and follws I(1). After a certain time one opens the switch T1, and the current I(a2) has to be redirected via diode D2 back to the source with I(2). This is because of the inductance of the machine acts as an emf restoring the flux stored in the magnetic field. Then one closes T1 again and so on. The chopping rate of switch T1 can be set in order to control the average current (Ia2), usually 1.5 times rated value. This is possible only if the speed is fast enough to provide terminal voltage. When the emf E reaches E=Ra.I(rated), the switch T1 remains closed for maximum breaking possible with the given emf. Four Quadrant Operation: Figure 8 summarizes the modes of operation in a four quadrant representation. Torque Speed Forward MOTORING Forward BREAKING Reverse BREAKING Reverse MOTORING Fig 8: 4 quadrant operation V2 N +Va (La, Ra) E Fig 7: Regenerative Control + T1 i2 i1 ia1 ia2 average Ia
What happen if the number of loops in the primary and secondary coils in a transformer are the same?
If the number of turns in the primary is the same as the secondary, this would be an isolation transformer. Primary and secondary voltages should match (minus the inherent transformer losses), as should the current.
How can transistors act as amplifiers or switches?
by creating two circuit loops
What are the application of differential compound generator?
Differential compounded generators are used in Ward Lenard motor generator loops. The shunt fields on these generators are separately excited and when the shunt field polarity is reversed by the controller the series field helps drive the generator voltage to zero thus aiding in the reversal of current.
Loops of wire that turn in the magnetic field of an armature create?
alternating current
What is a long coil of wire with many loops?
armature
When is the force experienced by current carrying conductor placed in a magnetic field strongest?
The force experienced by a current carrying conductor placed in a magnetic field is strongest when that conductor is placed perpendicularly to the magnetic field.
Would increase the strength of an electromagnet?
More coils of wire around the magnetic material.More current through the wire in the coil.Increasing the current flowing through the wire Increasing the number of loops of wireputting a piece of iron inside the loops of wire apex :)Increasing the current flowing through the wireIncreasing the number of loops of wire
How do you create energy from any movements?
The common way to do this is with a generator. The basic principle is quite simple: the movement makes wire loops move in a magnetic field; this induces electricity in the wire loops.
What is galvanometer magnetic force and motor effect?
A motor effect is when magnetic flux lines interact with the current flow in the current conducting wire (a production of current means there is a production of a magnetic field, thus the magnetic field of a permanent magnet interacts with the magnetic field of the current), hence causing a motor effect, where electric energy is transformed into mechanical energy. In a galvanometer, the concept of the motor effect is used for it to detect and measure the magnitude of small electric currents as an instrument. A galvanometer uses radial magnets which cover more area of the rotor (this is where the needle is attached), as this rotor consists of an armature and loops of wire, it is perpendicular to the magnetic flux lines of the radial magnet. Therefore as the current flows through the coil, a magnetic field is produced, and the motor effect occurs allowing the needle to move on the scale.
Ac relay and DC relay?
what is the meaning of ac relay and dc relay EDIT: a DC relay is simply a coil and core that pulls on an armature. An AC relay usually needs a shaded-pole core (couple of copper loops) to prevent the armature from vibrating at 60 cycles or so. The core, also, is laminated steel like a transformer; so is the armature to help contain the magnetic field. You should not substitute a DC rated relay for an AC , but the reverse should be ok, if voltage and current ratings are the same.
What happens when you add more coils to the wire in an electromagnet what else can you do to increase the magnetic field of an electromagnet?
The more loops gives the magnet more voltage. More loops produce more currents. The current that is induced as acts like an opposing magnet and makes it more difficult to move the magnet.
How many types of storage loops exits in magnetic bubble memory?
There are two types of storage loops exits in magnetic bubble memory.
Do magnetic field line complete loops?
no
What happens as you increasse and decrease the number of loops in an electromagnet?
With increase loops you create a larger charge, with decreased you will produce less current thus a smaller charge
What causes the loops of wire and the pointer to move in a galvanometer?
The electromagnet's coil is attached to a pointer. When a current is in the electromagnet's coil, a magnetic field is produced. This field interacts with the permanent magnet's field, causing the loops of wire and pointer to rotate.
