Toshiba GR-200 Series Instruction Manual page 358

How to determine thermal state of rotor (Mot-THSR operation)
The rotor heating caused by a single starting operation is expressed in Equation
(2.28-13):
At start-up I(t) = I
where:
T
T
θ
I
From Equation (2.28-14), the operation definition equation of Mot-THSR is Equation
(2.28-15).
Mot-THSR operates when Expression (2.28-15) is satisfied and the motor status is in
the "Stop" state.
The characteristic of the thermal state of rotor function is shown in Figure 2.28-16:
θ
r
θ
rm
Stop
Motor
Start-up
status
Running
Mot-THSR operation
Figure 2.28-16 Characteristic of thermal state of rotor function
I(t)
(
I
st
, then the expression becomes as Equation (2.28-14):
st
motor start-up time, defined by the setting [T-Mot-Start]
st
allowable locking time in the cold state, defined by the setting [T-Mot-LKRT]
sc
percentage of allowable thermal capacity of rotor,
rm
motor start-up current, defined by the setting [Mot-LKRT-IS]
st
(t) +
⁡θ
r
T
st
θ
rm
T
sc
2
1
∙ T
) ∙ ∙ ��
st
T rm
sc
T
st
∙ ��
rm
T
sc
T
st
≥ θ
∙ ��
T rm rm
sc
- 339 -
6F2T0200 (0.15)
(2.28-13)
(2.28-14)
defined by the setting [Mot-LKRT]
(2.28-15)
T
st
θ
(t) +
r
T
sc
θ
(t) : Rotor thermal state
r
t
GRE200 (1,2)
θ
rm