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Example 2
I
= 8.7 A
e
Motor cable looped four times (see fig. 4) =
4 × 8.7 A = 34.8 A. Setting 35 A.
Slide switches 4 and 5 moved to right
Contact 4 = 5 A
Contact 5 = 10 A
Basic value = 20 A
I
= 35 A
e
Star-delta starting
With star-delta starting, setting must be in
accordance with the phase current in delta
operation and motor protection relay TI 180 E
must be connected to the phase leads (fig. 9).
Rated operating current I
must therefore be
e
multiplied by the factor 0.58 (1:√
With looped connection also multiply by the
× 0.58 × no. of loops.
number of loops: I
e
Setting l
using overcurrent indication of
e
unit
If the rated motor operating current is not
known, set in accordance with the actual
operating current: with motor running under full
load reduce the current setting on TI 180 E (fig.
7, L) until the overcurrent indicator flashes (fig.
7, G). The set value corresponds to 91% of the
operating current. If this value is now increased
by 10% = (91%+9,1%=100%) the unit is set at
the rated motor operating current I
Example, fig. 10:
Indication (flashing) at 95 A; I
A. Setting: 104 A.
Setting of thermal relay trip time, fig. 7, K
Setting range: 2-30 s in steps of 2 s.
× I
The trip time t
at six times rated operating
6
e
current I
can be determined from the time/
e
current trip curves, fig. 3, a-f. The permissible
locked rotor time (from cold start) given by the
motor manufacturer must be converted to trip
× I
time t
as shown in the interpolation
6
e
example, pos. f. This value, rounded down to
the next smaller even number, must be set on
TI 180 E.
Legend for fig. 3:
Ultimate trip values to IEC 947-4
curve a trip curve from cold state with highest
possible trip time setting t
curve b trip curve from cold state with normal
× I
trip time setting t
6
curve d trip curve from cold state with lowest
possible trip time setting t
curve d trip curve with load I
highest possible trip time setting
× I
t
= 30 s and 2 s respectively.
6
e
curve e trip curve with load I
× I
time setting t
6
e
DKACT.PS.C20.A1.6D
Interpolation example:
Locked rotor current = 8.5 × I
locked rotor time (from cold state) = 17 s
The nearest trip curve (a) is parallel-displaced
through point (17 s/ 8.5 × I
6 × I
(fig. 7, K) must therefore be set on 24 s
(fig. 12).
Trip time setting with unknown locked rotor
time
In general, the normal setting for standard
motors t
rotor time is not given.
For special motors, e.g. thermally-critical
_
submersible pumps, the following procedure
3).
can be used if the locked rotor time is un-
known:
- Start with setting at 2 s
If the thermal relay trips, allow the motor to
cool down and repeat the start attempt with a
4 s setting.
- Continue in the same way setting increased
by 2 s until the motor starts.
Factory-set functions:
- Single-phasing and asymmetry (fig. 7, H)
- Overcurrent indication (flashing red at 1.1 ×
I
), (fig. 7, G)
e
- Automatic reset (option)
.
e
Commissioning
= 95 × 1.1 =
Connect supply voltage. The output relay pulls
e
and the green LED (fig. 7, F) signals ready.
Hold pushbutton (Test 6 × I
thermal relay trips, after the set time t
(fig. 7, K). This opens the output relay and the
red LED (fig. 7, G), thermal overload, will light
up. The green LED will go out at the same
time.
After a cooling time of about 6 × t
with t
(fig. 7, E).
Reset occurs immediately.
Test of thermistor overtemperature protec-
tion
Short-circuit thermistor inputs P1, P2 (fig. 7, D)
for about 0.5 seconds. The output relay will
drop out and the red LED (fig. 7, I) will light up
× I
= 30 s
while the green LED (fig. 7, F) will go out.
6
e
Pressing the reset button (fig. 7, E) resets the
= 10 s
motor protection relay immediately.
e
The motor can now be started.
× I
= 2 s
6
e
at lowest and
e
at normal trip
e
= 10 s
. Permissible
e
) and intersects line
e
. This gives 25 s. The slide switches
e
× I
= 10 s can be used if the locked
6
e
) down until the
e
× I
= 10 s) press the reset button
6
e
× I
6
e
× I
(i.e. 60 s
6
e
7
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