sepam 20 user manual - Schneider Electric

6
058731N
Installation 1 A/5 A Current transformers
ARJA1. ARJP3.
6/16
058733N
Function
Sepam may be connected to any standard 1 A and 5 A current transformer.
Schneider Electric offers a range of current transformers to measure primary
currents from 50 A to 2500 A.
Please consult us for further information.
Sizing of current transformers
Current transformers should be dimensioned so as not to become saturated by the
current values they are required to measure accurately (minimum 5 In).
For overcurrent protection
b Definite time:
The saturation current must be more than 1.5 times the setting value.
b IDMT:
The saturation current must be more than 1.5 times the highest working value
on the curve.
Practical solution when there is no information on the settings
Rated secondary
current in
Rated
burden
Accuracy
class
CT secondary
resistance RCT
Wiring
resistance Rf
1 A 2.5 VA 5P 20 < 3 Ω < 0.075 Ω
5 A 7.5 VA 5P 20 < 0.2 Ω < 0.075 Ω
PCRED301005EN - 06/2008