Thermal Overload Element Thma And Thmt; Testing Idmt For Ef And Sef Elements - Toshiba GRE110 Instruction Manual

Operating time check for IDMT curve
The testing circuit is shown in Figure 6.5.4.
Single-phase
current
source
+
Power
supply
−
Start
Time
counter
Stop
OV
(∗) :
Figure 6.5.4 Testing IDMT for EF and SEF Elements
One of the inverse time characteristics can be set, and the output signal numbers of the IDMT
elements are as follows:
Element
EF1
EF2
Fix the time characteristic to test by setting the scheme switch MEFI or MSEI on the "EF prot." or
"SEF prot." screen.
"Set.(change)" sub-menu → "Protection" screen → "Change set. (Act gp.= ∗)" screen → "Group∗"
screen → "Trip" screen → "Scheme sw" screen → "EF prot." or "SEF prot." screen
The test procedure is as follows:
•
Enter the signal number to observe the operating time at a binary output relay as shown in
Section 6.5.1 and press the ENTER key.
•
Apply a test current and measure the operating time. The magnitude of the test current should
be between 1.2 × I s to 20 × I s , where I s is the current setting.
•
Calculate the theoretical operating time using the characteristic equations shown in Section
2.1.1. Check that the measured operating time is within IEC 60255-151 class 5.
6.5.1.3

Thermal overload element THMA and THMT

The testing circuit is same as the circuit shown in Figure 6.5.2.
The output signal of testing element is assigned a configurable LED.
A
Connect the terminal number corresponding to the testing element.
Signal No. Element
63 SEF1
64 SEF2
 169 
6 F 2 T 0 1 7 2
GRE110
TB1
5
-
6
-
7
-
TB2-
8
-
BO ∗
TB1 -13
-14
-12
Signal No.
67
68
∗
( )
∗
-
( )