Toshiba GRT100 Series, Instruction Manual

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6.5.1.8 Thermal overload element THR
The testing circuit is shown in Figure 6.5.12.
Single-phase
current
source
A
TB 1 -1
-2
I a
GRT100
Monitoring
jack
A
0V
TB 4 - A16
- A17
E
DC
power
supply


Time
counter
Start
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 Signal number Remarks
THR-A_TEST 88 Alarm
THR-S_TEST 84 Trip
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 Operating time (

10%)
THR-A 11.5s (10.3s – 12.7s)
THR-S 22.5s (20.2s – 24.8s)