Most variable frequency drive displays can show me voltage, power and current output to the electric motor, I think all of these might be useful. Some drives can show Power Factor at the ac drives output - Why would I care?

I don't know that many VFD drives have a parameter to show the Power Factor for a motor as it is running on a drive. The ac drives have this as a parameter to look at. What does it tell me, other than the obvious angle between the current and voltage vectors.

The AC drive has a high power factory is good and having a low power factor is poor. For a given motor, it is said that power factory is fixed at the time of manufacturing and therefore once the system is installed it does not change. However for a given, motor power factory changes depending loading, name plate power factor is at 100% load but at 50% load the power factor drops. One of the advantages of using a VFD is as load changes on a motor; the power factor seen by the utility remains the same as the VFD drive. Putting it up on a display is a "nice to have" feature, it is nice to have time of day there too but not critical like current, voltage, or frequency.

Low power factor generally means higher operating costs. Many customers, including the military, often require and sometimes pay a premium for a higher power factor which means lower current, less energy lost, less copper, etc.

It doesn't mean anything to you. You already have the motor and you're not going to buy a new one to save pennies in operating costs

Power factor is an important key. It will give u an inside on the motor loading,reactive power pretty much a tool for preventive maintenance.What the VFD displays and how far it's true is a different question.

The motor power factor (assuming an induction motor) has no meaning to the power system when you are operating on an Adjustable Frequency Drive. There are several drives that operate just shy of 1.0 (on the lagging side) no matter what the torque or load is on the motor. Thus the electronic components of the ac drive make the motor invisible to the power system (power factor wise).

The power factor is a number that measures the efficiency of the use of the motor. Ideally a power factor = 1, which would mean the driving voltage and current are in phase. Some typical power factor numbers are more like 0.85.
Regards,

100% agree with Bill, you don't care of this for all days use of the variable frequency drive, it would be more useful to now reactive power you make in order to compensate it or see what you'll have to pay for this reactive power, but power factor...not very useful

Power factor is a measurement of reactive power. Reactive power is the VA used to establish the magnetic field in a motor. For permanent magnet motor, most time you see pf being unity, which means all VAs are used to generate torque (minus the loss, of course). Under the condition of field weakening operation though, you will see the PM motor gets less than unity pf because some VAs are used to counter the perm magnet field. In induction motor, the pf indicates the portion of VAs used to generate the field comparing to the VAs that generate torque ( and loss), which is related to the v/hz in scalar controller or Id in vector control. So under light load condition, you can improve the pf of a induction motor by lowering the field a bit.

As Bill pointed out, pf does affect the system performance. And there should be effort to improve it as part of the system adjustment, not only for the motor.

btw, max pf gets worse in induction motor when pole counts goes up.

As has been said, the motor power factor does not make a big difference other than giving an idea of loading. In regards to the variable frequency drive fixing power factor everyone is mostly correct. A VFD will always show a DPF (Displacement Power Factor) near unity. DPF is what a utility company traditionally monitors and is the measure of lag looking at current and voltage of power at 60hz or fundamental only. The true power factor on a VFD will change with loading etc and includes current and voltage inclusive of harmonics.