Toshiba GR-200 Series Instruction Manual page 349

where
θs thermal state of the stator as a percentage of allowable thermal capacity
θstop(0) thermal state of the stator at the instant when the motor stops
τ thermal cooling time constant (minutes) of the stator, defined by the setting
s2
[T-Mot-THM-rad]
The thermal state at the stator rises exponentially during motor operation to a certain
temperature that is determined by the current magnitude. When the motor has been stopped,
the stator temperature decreases to the ambient temperature.
Definition of the cooling time constant is necessary as well as the heating time constant. This
is usually supplied as motor data. Normally, the cooling time constant is three times the
heating time constant.
Scheme logic
The scheme logic of the thermal overload protection is illustrated in Figure 2.28-9.
8000111C23
Mot-THM A
8100111C27
T
Mot-THMA-EN On
MotSt-Irreg-Op
Mot-THMT-EN On
MotSt-Irreg-Op
810000EBB3 Mot-THMA_BLOCK
820000EBB4 Mot-THMT_BLOCK
Figure 2.28-9 Scheme logic of the thermal overload protection
Table 2.28-8 Settings corresponded for Mot-THM
Setting items
Mot-THMT-EN
Mot-THMA-EN
Mot-THM
T-Mot-THM
T-Mot-THM-rad
Mot-THM-Alarm
−��
θs = θstop ( 0 ) ∙ ��
& &
& &
1
1
Range Unit
Off / On - Thermal trip protection enable
Off / On - Thermal alarm function enable
0.40 - 10.00 A Thermal overload current
0.5 - 500.0 min Thermal time constant in generation of heat
0.5 - 500.0 min Thermal time constant in radiation state
Thermal alarm level multiplier
50 - 100 %
(Rate of [Mot-THM] setting)
- 330 -
⁄
��
× 100⁡(%)
��2
8100001B6E
8000001B6F
Contents
6F2T0200 (0.15)
(2.28-7)
Mot-THM-ALARM
Mot-THM-TRIP
Default
Off
Off
1.00
10.0
10.0
80
GRE200 (1,2)