USB fan looks like a resistive load?

[Faringdon]

Hi,
Would you agree, a low voltage (12v) DC fan , with a BLDC driver in front of it, looks like a resistive load, and not an inductive load?

[Andy Chee]

It completely depends on the load on the fan blades.

For example, if you stuck your finger into the blades and stalled the fan, what do you think the current and voltage waveforms would look like?

Or if you did a massive long fart into the fan and cause it to "windmill", what do you think the current and voltage waveforms would look like?

[Whales]

It depends on how much approximation you can tolerate.  What is the goal of this approximation?

Generally you don't approximate active electronics as R or L; instead you add lots of power rail capacitance in parallel so that you can pretend that it's a capacitive load with some varying parasitic resistance.

Do you care about turn-on transients?  It will look like a big capacitor.

Do you care about transients during motor load changes?  It might look inductive if you try and change the supply voltage because the motor can back-drive the H bridges and act as a generator. 

Does the driver support regen modes?