Toshiba GRT100 Series Instruction Manual page 128

6.5.1.8 Thermal overload element THR
The testing circuit is shown in Figure 6.5.12.

Single-phase
current

source

DC
power

supply
Start
Time
counter
Stop
OV
Figure 6.5.12 Testing THR (Model 100s, 200s)
This test is performed using time-shortened output signals because the operating time is in the
order of minutes. The operating time of the time-shortened signals is one sixtieth that of the
regular signals.
The time-shortened output signal number of the THR element is as follows:
Element
THR-A_TEST
THR-S_TEST
The short-time testing procedure is as follows:
 Set the relay :  = 60.0min, k = 1.30, I B = 1.00, I P = 0.80, T A = 10min
 Press 4 (= Logic circuit) on the "Test" sub-menu screen to display the "Logic circuit"
screen.
 Enter a signal number to observe the THR short-time output at monitoring jack A and
press the ENTER key.
 Apply a test current to 200% of the rated current and measure the operating time.
 Check that the measured operating time is within 10% of the following value.
Element
THR-A
THR-S
A
Signal number Remarks
88 Alarm
84 Trip
Operating time (10%)
11.5s (10.3s – 12.7s)
22.5s (20.2s – 24.8s)
 127 
6 F 2 S 0 7 8 9
GRT100
TB 1 -1
I a
-2
A
Monitoring
jack
0V
TB 4 - A16
- A17
E