Toshiba S2E21 - Manual (Page 70)

T O S H I B A
7.6 Settings on Fundamental Information
setting the protective characteristics of the according to fundamental
information alone that you can obtain from the rating nameplate of the motor, the
following steps should be taken.
In this case. however, use overly conservative characteristics to ensure the
motor safety. Note that the temperature rises S, are different from
the actual motor temperature rises.
To perform accurate temperature rise simulation and protection, it is necessary
to set the motor constants.
information:
motor rated current
CT: CT current (A)
allowable motor temperature rise
TSC : allowable motor locking time during cold condition
Tst: starting time
1st: starting current
20-Z: CT ratio (given)
20-3: ratio 50 A
This does not affect the protection characteristics.
20-4: rated setting (I
N
).
This is calculated by the following equation:
=
21-2: Setting of the heating time constant
TR 3 x Tst
Hhen Tst is less than 3, setting should be
TR = 10
21-4: Setting of the cooling time constant
It should be set to 0 = 3 x