Toshiba – Toshiba S2E21 User Manual
Page 63
TOSHIBA
Where
temperature rise of the rotor at time t
S: temperature rise of the
at time t (C)
TR:
heating time constant of the motor (minute) (set value)
When the load current is higher than 2.5 times the rated current
(2.5 x IN
From the heating characteristic during locking that
by the
motor starting current (1st) and the allowable locking time. the temper-
ature rise of the rotor is simulated.
When at time the rotor is locked, then
l(t),
1
=
) .
.
TSC
t
. . . . . . . . . . . . . ...(5)
Where R(t): temperature rise of the rotor at time t
temperature rise of the rotor before the rotor is
locked (C)
load current at time t (A)
starting current (A) (setting value)
TSC:
allowable locking time in the cold state
(setting value)
allowable temperature rise of the rotor CC)
(fixed at
When
=
the trip operation is carried out.,
The operation characteristic (operating time) in the locked state varies
depending on the heated condition of the motor and the conducting current.
110