Alternator run at zero power factor lagging

In summary, an alternator running at zero power factor lagging indicates that the device is operating in a state where the current and voltage are out of phase, meaning that the active power (real power) is zero while reactive power is at its maximum. This situation occurs when the alternator is supplying reactive power to the grid, which can lead to inefficiencies and potential overheating. It is essential for the alternator's design and operational parameters to manage such conditions effectively to maintain stability and performance within the electrical system.
  • #1
electricalguy
Gold Member
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Hello, I'm wondering if it's possible to make an alternator run at zero power factor lagging (purely inductive). I was researching this topic and apparently by shorting the leads of the alternator the output will become fully reactive. Yet I've attempted this on a small scale and the most I can get the phase between voltage and current to shift is 45°. I've increased the excitation current without a change in the phase angle. Is there something I'm missing? Is there a way I can make the alternator run purely inductive? I understand lagging power factor is demagnetizing, leading power factor is magnetizing and unity power factor is cross magnetized. Is the issues with the resistance of the stator winding?
 
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  • #2
In reality - I doubt this is possible with passive components as there will always be real losses.

If you are shorting the output - how are you measuring the voltage in taking the PF?
 
  • #3
I'm using an oscilliscope to take measurements of the line voltage and the phase current. I used a 14 gauge wire to connect the phases together. I measure the current waveform across the 14 gauge wire. I measure the difference in time between the voltage and current waveforms in milliseconds, then divide by one AC cycle in milliseconds, then multiple by 360 and this gives me the phase angle between the two in degrees.
 

FAQ: Alternator run at zero power factor lagging

What does "zero power factor lagging" mean for an alternator?

Zero power factor lagging means that the alternator is supplying reactive power only, with no real power being delivered. The current lags the voltage by 90 degrees, indicating purely inductive load characteristics.

Why would an alternator be run at zero power factor lagging?

An alternator might be run at zero power factor lagging to provide reactive power compensation to the grid. This helps in voltage regulation and improves the power factor of the system, which can enhance overall efficiency and stability.

What are the effects on the alternator when running at zero power factor lagging?

Running an alternator at zero power factor lagging increases the reactive power flow, which can lead to higher currents in the stator windings. This can cause additional heating and potentially reduce the lifespan of the alternator if not managed properly.

How is the excitation system adjusted for zero power factor lagging operation?

The excitation system must be adjusted to increase the field current, which boosts the magnetic field strength. This helps the alternator to generate the necessary reactive power while maintaining the desired voltage levels.

What are the potential risks of operating an alternator at zero power factor lagging for extended periods?

Extended operation at zero power factor lagging can lead to excessive heating of the alternator windings and core, increased mechanical stress, and potential insulation degradation. It is crucial to monitor the temperature and other operational parameters to prevent damage and ensure reliable performance.

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