ABB HU Instruction Leaflet page 18

41-347.12C
Restraint
Transformer
Tap
Smaller
2.9
3.2
3.5
3.8
4.2
4.6
5.0
8.7
right-hand (front view) side of the polar unit.
Bring up the stationary contact until it just
makes with the gage. Tighten mounting
screw in the elongated hole of the stationary
contact and remove gage.
2. Minimum Trip Current
A. Harmonic Restraint Unit (HRU)
1. Polarization Test - Connect the relay per test
circuit of figure 16. Close SPDT switch to
position 2 and open SPST switch (I
Pass I = 0.8 times tap value current (4
dc
amperes dc on 5 ampere tap) into the relay.
2. Pickup and Dropout Adjustment - After unit
has been polarized, open SPDT switch (I
0) and close SPST switch. Set I
18
Larger 2.9 3.2
I 8.7 8.7
SR
I (Min) 2.6 3.7
AC
I (Max)
2.8 4.0
AC
I 9.6
SR
I (Min) 2.7
AC
I (Max)
3.1
AC
I
SR
I (Min)
AC
I (Max)
AC
I
SR
I (Min)
AC
I (Max)
AC
I
SR
I (Min)
AC
I (Max)
AC
I
SR
I (Min)
AC
I (Max)
AC
I
SR
I (Min)
AC
I (Max)
AC
I
SR
I (Min)
AC
I (Max)
AC
= 0).
ac
= 30% of
ac
Table 2:
3.5 3.8 4.2
Current in Amperes
8.7 8.7
5.0 5.8
5.5 6.4
9.6 9.6
4.0 4.9
4.4 5.4
10.5 10.5 10.5
3.0 3.8
3.3 4.2
11.4 11.4
3.2
3.6
12.6
tap value current and adjust the right-hand
shunt on the upper unit until it operates.
Lower Iac gradually to 15% of tap value cur-
rent and adjust the left-hand shunt until the
unit resets.
Repeat the polarization tests, pickup and
dropout tests until the unit performs as follows
with no further adjustment of the shunts.
a. The unit operates between 28% to 30% of
tap value current immediately after the appli-
cation of polarization current of Idc = 0.8
times tap value current. The unit will reset at
a value of current 15% of tap value current or
=
dc
greater.
4.6 5.0 8.7
8.7 8.7 8.7
7.8 9.0 10.4 16.2
8.6 10.0 11.6 17.9
9.6 9.6 9.6
6.9 8.1 9.6 15.7
7.6 9.0 10.6 17.3
10.5 10.5
5.7 6.9 8.3 14.5
6.3 7.7 9.2 16.1
11.4 11.4
5.2 6.5 7.9 14.1
5.7 7.2 8.7 16.0
12.6 12.6
3.5 4.7 6.2 12.9
3.9 5.2 6.9 14.2
13.8 13.8
3.9 5.3 12.4
4.3 5.9 13.7
15.0 10.0
4.3 11.6
4.8 12.9
17.4
5.8
6.4
7.0
7.6
8.4
9.2
5.0
5.5