Toshiba S2E21 - Page 73

TOSHIBA
6F9EOlll
'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. 1st 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 (TSC)
Given value (Consult motor manufacturer)
25-3: Starting current (1st)
See motor data (at full voltage.)
25-4: Starting time (Tst.)
- Convert the actual starting time to setting value based 1st.
Ist.act
Tst = ( -
)* * Tst.act
1st
Where Tst : starting time (setting value)
Tst.act : actual starting time at reduced voltage.
1st : starting current (motor data at full voltage)
I&act : 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
re&reen P4. (See manual page 50,4-4.')
Following the above procedure protects the motor under a full voltage
locked-rotor condition and allows a longer starting time for reduced
voltage(reduced inrush current) starting.
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