Thermal Curves; Thermal Overload Protection Scheme Logic - Toshiba GRE110 Instruction Manual

that has previously been loaded to 90% of its capacity.
Thermal Curves (Cold Curve - no
prior load)
1000
100
10
1
0.1
0.01
1
Overload Current (Multiple of I
Scheme Logic
Figure 2.5.2 shows the scheme logic of the thermal overload protection.
The thermal overload element THM has independent thresholds for alarm and trip, and outputs
alarm signal THM ALARM and trip signal THM TRIP. The alarming threshold level is set as a
percentage of the tripping threshold.
The alarming and tripping can be disabled by the scheme switches [THMAEN] and [THMTEN]
respectively or binary input signal THM BLOCK.
77
A
THM
78
T
[THMAEN]
+
"ON"
[THMEN]
+
"ON"
THM BLOCK
Figure 2.5.2 Thermal Overload Protection Scheme Logic
Thermal Curves (Hot Curve -
1000
100
10
1
τ
100
0.1
50
20
10
0.01
5
2
0.001
1
1
10
Overload Current (Multiple of I
)
AOL
Figure 2.5.1 Thermal Curves
&
&
1
 37 
90% prior load)
τ
50
20
10
5
2
1
10
)
AOL
THM ALARM
THM TRIP
6 F 2 T 0 1 7 2