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TOSHIBA
7.6 Settings llased on Fundamental Information
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.
the actual motor temperature rises.
To perform accurate temperature rise simulation and protection, it is necessary
to set the motor constants.
CT:
TSC :
Tst:
1st: starting current (A)
20-Z: CT ratio (given)
20-3: ZCT ratio 50 A
20-4: rated cZ%it setting (I
21-2: Setting of the heating time constant (TR)
21-4: Setting of the cooling time constant (TD)
Note that the temperature rises (6 S, 8 R) are different from
CT cecondary current (A)
allowable motor locking time during cold condition
starting time (set)
This does not affect the protection characteristics.
This is calculated by the following equation:
TR (min) ) 3 x Tst
Hhen Tst is less than 3, setting should be
TR = 10 (min)
It should be set to 0 (TD = 3 x TR)
).
N
according to fundamental
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