Toshiba GR-200 Series Instruction Manual page 354

Motor in actual operating condition
In the actual operating condition, θr(0) is able to stay among 0 and θsn in Equation
(2.28-10). As a results, the operating time Top is given by Equation (2.28-12).
where
Top operating time in actual operating condition
The IEC 60255-8 curves of the Mot-LKRT relay characteristic is illustrated in
Figure 2.28-12 and Figure 2.28-13.
Figure 2.28-12 shows the curve in the case where the motor current is less than 2.5
times the motor rated current, and Figure 2.28-13 shows the curve in the case where
the motor current is larger than 2.5 times the motor rated current.
Figure 2.28-12 Thermal curve of locked rotor protection (I < 2.5x[Mot-Ir])
��������������[Mot-Ir]
��������������[Mot-THM]
�� − �� (0)
���� ��
�� =
����
��
����
Thermal Curves of
Locked Rotor Protection (I < 2.5x[Mot-Ir])
(0% of prior load)
Current (Multiple of k.IFLC)
- 335 -
×100(%)
∙ ��
����
Ts (min)
100
50
20
10
5
2
1
6F2T0200 (0.15)
(2.28-12)
GRE200 (1,2)