Electronics > Beginners

Dynamic load, does that exists?

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FriedMule:
I was thinking of it is possible to bye a dynamic load, i.e. to simulate a motors behavior?
A sort of reverse universal function generator.

JS:
  Which kind of motors are you trying to simulate?

  There's a topic around here about a dynamic load, but it's just for DC+pulses.. then there's a second thread modifying that load to accept a sig gen as input reference, but in any case 1 quadrant only, it wouldn't be that hard to translate it to two quadrants to be able to load AC signals but getting it to work in 4 quadrants to emulate a reactive load is more tricky.

JS

FriedMule:
JS - Hi sorry that I forgot that, it is for "low" DC voltage only <15V 2A

Have thought about using a combination with a function generator, via some BJT / FET but do not know how.

T3sl4co1l:
Yes, a programmable load, or SMU (source measure unit), would be able to automate that.

To a certain extent, a PMDC motor acts like an RLC circuit, with L = winding inductance, R = winding resistance and C = rotor inertia (as reflected through the motor's EMF).  Then an R in parallel with the C to represent mechanical load.  And maybe some other quirks, depending on how accurate you want the model, like

I think it would be reasonable enough to model a small motor with a pile of electrolytic capacitors.  The main problem is that the rotor inertia has a large equivalent capacitance, like 10s of mF.

This may be simpler than building a two quadrant load.  If you have an example motor with parameters, we can show how to derive these values.

(Downside: a passive model won't generate the ripple and commutator noise of a real motor!)

Tim

FriedMule:
This time it is a motor, next time an amplifier, heater or what ever:-)
What I really would like is the same as if you think of a universal function generator. You measure the project with your oscilloscope, transfer the result to an universal function generator and it delivers the same waveform.
Why not a load that could take the data from the oscilloscope and then generate the same load pattern? I.e. motor start, inrush current or something else? :-)

Do that not exist, what do other use to manage the task precisely?

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