Toshiba S2E21 - Manual (Page 73)

TOSHIBA
'7.7 Settings For Reduce Voltage Starting
For reduce voltage starting, the actual starting current is different from
the nameplate of the motor.
Perform the following steps for setting of TSC. and Tst for locked-rotor
protection. In this case, Auto learning function of Tst and 1st should not
be turned on.
25-2: Setting of allowable locked-rotor time in cold condition
Given value (Consult motor manufacturer)
25-3: Starting current
See motor data (at full voltage.)
25-4: Starting time
Convert the actual starting time to setting value based 1st.
Tst =
1st
Where Tst starting time (setting value)
actual starting time at reduced voltage.
1st : starting current (motor data at full voltage)
: actual starting current at reduced voltage.
Actual starting time should be calculate based on motor torque
and load. or after one start read screen P4. (See manual page 50,
4-4.)
Actual starting current should be calculated, or after one start
P4. (See manual page
Following the above procedure protects the motor under a full voltage
locked-rotor condition and allows a longer starting time for reduced
inrush current) starting.
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