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What is the formula for armature resistance of shunt excited DC generator?
The armature resistance of a shunt excited DC generator is calculated using the formula ( R_a = \frac{V - E}{I_a} ), where ( R_a ) is the armature resistance, ( V ) is the terminal voltage, ( E ) is the generated EMF (electromotive force), and ( I_a ) is the armature current. The difference between the terminal voltage and the generated EMF accounts for the voltage drop across the armature resistance due to the current flowing through it.
How do you calculate armature current in a shunt generator?
To calculate the armature current in a shunt generator, you first need to determine the load current (I_load) and the shunt field current (I_shunt). The armature current (I_a) can then be calculated using the formula: ( I_a = I_{load} + I_{shunt} ). The shunt field current can be found using the field resistance and the terminal voltage. Once you have both currents, simply add them to find the total armature current.
How do you work out Armature current?
To calculate armature current in an electrical machine, you can use the formula: ( I_a = \frac{P_{out} + P_{loss}}{V_{a}} ), where ( I_a ) is the armature current, ( P_{out} ) is the output power, ( P_{loss} ) represents losses (like copper losses and iron losses), and ( V_{a} ) is the armature voltage. Alternatively, if you know the load resistance and applied voltage, you can use Ohm's Law: ( I_a = \frac{V_a}{R} ), where ( R ) is the load resistance. Ensure to account for any back EMF in your calculations for accurate results.
What will happen if the armature rheostat is zero and field circuit resistance is kept high in a dc motor?
If the armature rheostat is set to zero and the field circuit resistance is kept high in a DC motor, the armature will receive maximum current, leading to a high armature current. However, with a high field circuit resistance, the field current will be low, resulting in a weak magnetic field. This imbalance can cause the motor to run at a very high speed, potentially leading to instability or damage due to excessive armature current and insufficient torque production. Overall, the motor may operate inefficiently and could risk mechanical failure.
What is ammature resistance?
Right now a DC engine is begun the armature is stationary and there is no counter EMF being produced. The main part to cutoff beginning current is the armature resistance, which, in most DC engines is a low esteem.
Why armature resistance has to be measured at rated current?
Armature resistance is measured at rated current to ensure that the resistance reflects the operational conditions under which the machine will typically run. This measurement accounts for factors such as temperature, which can affect resistance values, ensuring accuracy in performance predictions. Additionally, testing at rated current helps identify any potential issues that may arise during normal operation, such as overheating or inefficiencies. Overall, this approach provides a more realistic and reliable assessment of the armature's performance in practical applications.
Why the armature rheostat of dc is motor kept at maximum resistance position?
It isn't. It is only kept at maximum resistance when the motor is not running. That is done to limit the starting current.
Why the armature current of a shunt motor decreases as the motor accelerates?
Without a mechanical load the motor accelerates until the back-emf generated by the armature nearly equals the supply voltage. On load, the speed drops and the current rises until the power taken from the supply balances the mechanical power supplied to the load. If the armature has low resistance, the speed drop under load is not very much, so speed regulation is better if the armature resistance is lower.
What determinesthe amount of current produced in the armature of a generator?
The amount of current produced in the armature of a generator is primarily determined by the voltage induced in the armature winding, the resistance of the circuit, and the load connected to the generator. According to Ohm's Law, current (I) is equal to voltage (V) divided by resistance (R) (I = V/R). Additionally, factors such as the speed of rotation of the generator, the strength of the magnetic field, and the number of turns in the coil also influence the induced voltage and, consequently, the current generated.
What is the formula for electrical resistance?
Resistance(Ohms)= Voltage(volts)/Current (Ampheres) -X
What is armature magnetomotive force?
Armature magnetomotive force (mmf) is caused by current flow in armature windings. The source of mmf is armature reaction that is why the term "armature" is used.AnswerMagnetic circuits are often compared with electriccircuits. A magnetomotive force (equivalent to 'voltage') creates magnetic flux (equivalent to 'current'), which is opposed by reluctance (equivalent to 'resistance').So a magnetomotive force is the source of magnetic flux, and is the product of the current passing through a winding and the number of turns of that winding. In SI, it is expressed as amperes (although it is generally 'spoken' as ampere-turns).As the original answer explains, an armature magnetomotive force is simply that set up by the current passing through the machine's armature.
What is the current in a circuit that has a resistance of 30 ohms and a power of 2 watts?
To find the current in the circuit, you can use the formula: Power = Current^2 * Resistance. Given the values, you can rearrange the formula to solve for current: Current = sqrt(Power / Resistance). Plugging in the values, you get Current = sqrt(2 / 30) which simplifies to approximately 0.27 amperes.
