ERL MIT161 - Operating Characteristics and Accuracy; Output Contacts and Burden

9
6.5. Operating Characteristics
Earth Fault element Definite Time Lag (DTL)
Low set element Standard Inverse 3 sec (SI3)
Standard Inverse 1.3 sec (SI1)
Very Inverse (VI)
Extremely Inverse (EI)
Long Time Inverse (LTI) or
Definite Time Lag (DTL)
DTL Operating time 0 to 20.00 sec in steps of 0.01 sec
IDMTL Operating Time can be calculated as follows
K x T
M
T =
(I/I
S
)
α
- 1
Where I – Fault current
I
S
– Setting current
T
M
– Time Multiplier Setting
SI3 K = 0.14 α = 0.02
SI1 K = 0.0613 α = 0.02
VI K = 13.5 α = 1.0
EI K = 80.0 α = 2.0
LT1 K = 120.0 α = 1.0
6.6. Accuracy
Starter 104% of setting ± 4%
Reset ≥ 94% of setting
Repeatability ± 1%
IDMTL Operate Time ± 5% or ± 35 m.sec
DTL Operate Time ±1% or ± 35 m.sec.
6.7. Output Contacts
6.7.1. T
HE RELAY HAS
5
OUTPUT RELAYS
1. Common trip / alarm relay 2 N/O
2. Common Starter 1 C/O
3. Earth Fault operated 1 N/O
4. Low set operated 1 N/O