Motors

ElectroStores

MOTORS:

How can a locked rotor condition be defined....from a devices point of view: We know it means the motor has stalled with power on the terminals and is probably pulling a horrendous amount of amps... This is How Schneider does it with their softstarter: from AltiStart maintenance repair guide Locked Rotor Fault Description This fault appears if the motor draws more than 5 times its rated current (the level set by the parameter In) in any one of the motor legs for more than 200 ms. This overcurrent detection is only active when the motor is up to speed and a bypass/shorting contactor is engaged. This fault is stored in the fault history.·
And this was unexpected Overcurrent Fault Description This fault appears if too much current is instantaneously drawn through the soft start. • When the soft start is running, the fault occurs if the measured current is greater than 10 times the soft start's current rating (Icl) in at least one phase for at least 10 ms. • When the soft start is not running, the fault occurs if the measured current is greater than 6% of the soft start's rated current (Icl) in at least one phase for at least 200 ms. An overcurrent fault can also occur if the soft start cannot synchronize its firing circuits with the AC line within 500 ms after commanding the shorting/bypass contactor to open.