Hi,
Under excitation - inductive reactive power
Over excitation - Capacitive reactive power.
The induction motor is the special kind of motor which runs below and above the synchronous speed. which the synchronous motor runs nearly equal the synchronous speed. The operation of synchronous motor runs with dc field excited hence separate dc field current is given to the field circuit. where as the induction motor the field and main field is drawn from the same supply hence no excitation is required. But due to this separate starting mechanism has to be required in case of the single phase induction motor.
Synchronous motors show some interesting properties, which finds applications in power factor correction. The synchronous motor can be run at lagging, unity or leading power factor. The control is with the field excitation, as described below:When the field excitation voltage is decreased, the motor runs in lagging power factor. The power factor by which the motor lags varies directly with the drop in excitation voltage. This condition is called under-excitation.When the field excitation voltage is made equal to the rated voltage, the motor runs at unity power factor.When the field excitation voltage is increased above the rated voltage, the motor runs at leading power factor. And the power factor by which the motor leads varies directly with the increase in field excitation voltage. This condition is called over-excitation.The most basic property of sycho motor is that it can be use as a CAPACITOR OR INDUCTOR both. Hence in turn it improves the power factor of system.The leading power factor operation of synchronous motor finds application in power factor correction. Normally, all the loads connected to the power supply grid run in lagging power factor, which increases reactive power consumption in the grid, thus contributing to additional losses. In such cases, a synchronous motor with no load is connected to the grid and is run over-excited, so that the leading power factor created by synchronous motor compensates the existing lagging power factor in the grid and the overall power factor is brought close to 1 (unity power factor). If unity power factor is maintained in a grid, reactive power losses diminish to zero, increasing the efficiency of the grid. This operation of synchronous motor in over-excited mode to correct the power factor is sometimes called as Synchronous_condenser.
the excitation voltage applied the power input to the prime mover
If the synchronous motor is running near synchronous speed, it will begin rotating at synchronous speed when DC is applied to the rotor. Source: Electrical Machines, Drives, and Power Systems Theodore Wildi Section 17.3
A synchronous motor can operate as either a Generator or a Motor.When a synchronous motor has current applied to the windings on its rotor and the stator is energized with say a 50hz line supply (with little or no physical load) then the exact amount of excitation provided by the rotor can determine whether the stator displays inductive or capacitive properties.If the rotor is under excited (too Little rotor current) the Synchronous Motor will behave as an Inductor, however if the rotor is over excited then the Synchronous Motor will behave like a Capacitor.Hope this helps
yes
The induction motor is the special kind of motor which runs below and above the synchronous speed. which the synchronous motor runs nearly equal the synchronous speed. The operation of synchronous motor runs with dc field excited hence separate dc field current is given to the field circuit. where as the induction motor the field and main field is drawn from the same supply hence no excitation is required. But due to this separate starting mechanism has to be required in case of the single phase induction motor.
DONT KNOW AN OF THEM 10/4 over & out
yes. excitation current is same as field current to my knowledge
something cool
Synchronous motors show some interesting properties, which finds applications in power factor correction. The synchronous motor can be run at lagging, unity or leading power factor. The control is with the field excitation, as described below:When the field excitation voltage is decreased, the motor runs in lagging power factor. The power factor by which the motor lags varies directly with the drop in excitation voltage. This condition is called under-excitation.When the field excitation voltage is made equal to the rated voltage, the motor runs at unity power factor.When the field excitation voltage is increased above the rated voltage, the motor runs at leading power factor. And the power factor by which the motor leads varies directly with the increase in field excitation voltage. This condition is called over-excitation.The most basic property of sycho motor is that it can be use as a CAPACITOR OR INDUCTOR both. Hence in turn it improves the power factor of system.The leading power factor operation of synchronous motor finds application in power factor correction. Normally, all the loads connected to the power supply grid run in lagging power factor, which increases reactive power consumption in the grid, thus contributing to additional losses. In such cases, a synchronous motor with no load is connected to the grid and is run over-excited, so that the leading power factor created by synchronous motor compensates the existing lagging power factor in the grid and the overall power factor is brought close to 1 (unity power factor). If unity power factor is maintained in a grid, reactive power losses diminish to zero, increasing the efficiency of the grid. This operation of synchronous motor in over-excited mode to correct the power factor is sometimes called as Synchronous_condenser.
the excitation voltage applied the power input to the prime mover
If the synchronous motor is running near synchronous speed, it will begin rotating at synchronous speed when DC is applied to the rotor. Source: Electrical Machines, Drives, and Power Systems Theodore Wildi Section 17.3
John Griffiths Barry has written: 'Some effects of variable excitation on synchronous motor oscillation ..' -- subject(s): Synchronous Electric motors
A synchronous motor can operate as either a Generator or a Motor.When a synchronous motor has current applied to the windings on its rotor and the stator is energized with say a 50hz line supply (with little or no physical load) then the exact amount of excitation provided by the rotor can determine whether the stator displays inductive or capacitive properties.If the rotor is under excited (too Little rotor current) the Synchronous Motor will behave as an Inductor, however if the rotor is over excited then the Synchronous Motor will behave like a Capacitor.Hope this helps
A synchronous condenser (also known as a synchronous capacitor or synchronous compensator) is a DC-excited synchronous computer (large rotating generators) whose shaft is now not connected to any using equipment.
A synchronous motor can operate as either a Generator or a Motor.When a synchronous motor has current applied to the windings on its rotor and the stator is energized with say a 50hz line supply (with little or no physical load) then the exact amount of excitation provided by the rotor can determine whether the stator displays inductive or capacitive properties.If the rotor is under excited (too Little rotor current) the Synchronous Motor will behave as an Inductor, however if the rotor is over excited then the Synchronous Motor will behave like a Capacitor.Hope this helps