Two-stages current relay
Two-stages overcurrent relay is intended to be used in protection systems in order to control the RMS value of sinewave or DC current. Digital technology provides high accuracy, stability and dependability.

Manuals, diagrams, technical details


Product description

Protection set

51 definite-time overcurrent protection

Main features

  • One phase measuring circuit
  • Two definite-time overcurrent stages
  • Measuring and continuous displaying of energising value
  • Record of value of voltage during last disturbance
  • Binary input in order block relay operation
  • LED display and set of buttons in order to operation of the relay
  • Optical indicating (with LED diodes) current voltage value (U<U1, U1<U<U2, U>U2), external blocking signal and proper operation of relay
  • Relay output for signalling: pick-up of I or II stage (K1), operation of I stage (K2), operation of II stage (K3), failure or lack of aux. voltage (K4) or relay interlock by external signal (K5)
  • Self-test of proper operation of relay
  • Relay enclosure gives possibility to mount on 35 mm rail, surface mount or flush mount

The RIT-400A relay measures the value of current and compares it to the threshold value set by the user. If the measured value exceed one of the threshold values, the relay operates according to selected operation mode. Possible operation modes are: overcurrent or overcurrent with interlock. The interlocked operation mode depends on binary signal fed to binary input (Ubl).


Rated measuring current In 1A, 5A,
1/5A (selectable)
Rated frequency fn 50Hz
Auxilliary voltage 24V DC, 48V – 60V DC,
110V – 230V DC/AC
Setting range of current threshold value (0,05÷5)In or (0,2÷20)In
Accuracy of current inputs 2,5%
Relay response time ≤40ms
Setting range of operating time (0÷99,9)s
Burden in measuring input ≤0,5VA
Burden of supply module ≤6W
Continuous measuring current 2,2 In
Thermal withstand (1s) 80 In
Dynamic withstand 200 In
Relay outputs data – trip purposes outputs (K1, K2, K3):
Max. breaking capacity by 250V DC
– resistive load 0,3A
– inductive load of L/R ≤40ms 0,12A
Max. breaking capacity by 250V, 50Hz
– inductive load, cosϕ=0,4 3A
Continuous contact carry 5A
Relay outputs data – signalling purposes outputs (K4, K5):
Max. breaking capacity – resistive load
– AC current 6A
– DC current 6A/28V; 0,16A/220V
Continuous contact carry 5A
Ambient temperature (268÷313)K/(-5÷40)°C
Relative humidity ≤80%
Ingress Protection degree IP40
Weight 0,7kg
Dimensions (height x width x depth) 75 x 100 x 120 mm
Electromagnetic compatibility according to EN 50263
Insulation according to EN 60255-5

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