Speed Loop and Current Loop Basics

What do you do?

design or repair? or only aware of it?

simple words, they will construct a close loop system which can made motor run stably. current loop has less time constant than speed loop has. so that they will have more sensitive at current control.

this system can be implemented by an inverter, if you hope to buy availble on the market, current and speed feedvack signal acquired from sensors to its inputs. of cause if there is no such sensor, inverter can work well as well, but its belong to open control, you can imagine, it has no better features and no as well pricise as this two loop control.

speed and current will have different uses

for a steady speed, you'll have a variable current (usually torque drives)

for a steady current you can have variable speed...