LAURITZ KNUDSEN / ELECTRICAL & AUTOMATION
Numerical protection relays
Protection relay products for specified power-system schemes.
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numrAL relays
02
Earth-fault protection
03
Reverse power relays
MANUFACTURER REFERENCE / August 2026
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ESP Lauritz Knudsen Price List (1).pdf ↗ · PDF pages 105–109
5 catalog pages
PDF page 105 Protection Relays [8536]
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Protection Relays [8536]
Correlation between ANSI/IEEE device function number and relays
ANSI Code Function Name Protection Relays
Voltage and
Single Function Feeder Motor Protection
Frequency
eMPR
REF11 NDR11 OCR11 RPR11 TCS11 PTF11 VPR11 VPR21 VPR22 FDR21 FDR22 iMMR MM10 MPR21
300I
27 AC under-voltage relay ü ü ü ü
32 Power directional relay ü
Under current or under
37 ü ü ü ü
power relay
Reverse phase or phase
46 ü ü ü ü ü
balance current relay
Broken conductor
46BC ü
Protection
Phase-sequence or
47 single-phasing voltage ü ü ü
relay
Excessive Start Time
48 ü ü ü
Monitoring
Machine or transformer
49 ü ü ü ü ü
thermal Overload relay
Instantaneous
50 ü ü ü ü ü
overcurrent relay
Instantaneous Earth
50N ü ü ü ü ü
Fault relay
50BF Breaker - failure ü ü ü
AC time over current
51 ü ü ü ü ü
relay
Ground fault time over
current relay /
51N-(51G) ü ü ü ü ü
Standby Earth Fault
Relay
51LR Locked rotor ü ü ü ü
59 AC over-voltage relay ü ü ü ü
Neutral Displacement
59N ü ü ü
Relay
Positive Sequence
59D ü ü
Over-voltage protection
Restricted Earth Fault
64REF ü
Relay
64 Machine Ground Fault ü ü ü ü ü
66 Max. no. of starts ü ü
81 Frequency relay ü ü ü
Ground fault differential
87N-(87G) ü
protection relay*
Trip Circuit supervision
74TCS ü ü ü ü
Protection
Vector surge protection
78 ü
relay
Rate of change of
df/dt ü
frequency
Switch On to Fault
SOTF ü
Protection
PTFF PT Fuse failure ü
* REF11 is meant for Generator Differential Protection
Lauritz Knudsen, 15.08.2026 98PDF page 106 numrAL – Numerical Protection Relays with Draw-out enclosure [8536]
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numrAL – Numerical Protection Relays with Draw-out enclosure [8536]
3 Phase non-directional Single Pole Over Voltage + Under Voltage Relay
Over Current + Earth Fault Relay
VPR11 - Single Pole Under Voltage and Over Voltage Relay (27, 59)
› FDR21 – 50, 51, 50N, 51N. › Microcontroller-based design
› Microcontroller-based design › Draw-out Enclosure
› Draw-out enclosure. › Single Phase OV + UV Protection
› CT rating#- 1A/ 5A (site selectable) › System Voltage – 110/ 230/ 415 VAC
› Display of 250 event and 30 Trip records (site programable)
› 128*64 graphical display › Inverse and definite time delay
› Display of Actual value and 5 Trip records
Aux. Supply (V) M.R.P. (`)
Model Communication Cat. No.
Per Unit
20 - 60V DC Non-Communicable NRFDR2A26NX 29680 M.R.P. (`)
numrAL Model Aux. Supply (V) Communication Cat. No.
85 - 265V AC, Per Unit
FDR21 Non-Communicable NRFDR2B26NX 29680
87 - 265V DC 20 - 60V DC Non-communicable NRVPR1A11NX 21560
#
- Protection Class CT 85 - 265V AC,
Non-communicable NRVPR1B11NX 21560
numrAL 87 - 265V DC
VPR11 20 - 60V DC Modbus RS 485 NRVPR1A11RA 26400
3 Phase non-directional 85 - 265V AC,
Modbus RS 485 NRVPR1B11RA 26400
87 - 265V DC
Over Current + Earth Fault Relay
› FDR22 - 46BC, 49, 50, 51, 50N, 51N, 50BF, 74TCS, SOTF
› Microcontroller-based design
› Draw-out enclosure.
› CT rating#- 1A/ 5A (site selectable)
› Display of 250 event and 30 Trip records
› 128*64 graphical display
› Modbus RS-485 Communication 3 Phase Voltage + Frequency Relay
› Front Micro USB port for numrAL Suite
› VPR21 – 27, 47, 59, 59N, 81O/U
M.R.P. (`) › Microcontroller-based design
Model Aux. Supply (V) Communication Cat. No.
Per Unit › Draw-out enclosure.
20 - 60V DC Modbus RS 485 NRFDR2A27RA 37520 › System Voltage – 110/ 230/ 415 VAC
numrAL
FDR22 85 - 265V AC, (site programable)
Modbus RS 485 NRFDR2B27RA 37520
87 - 265V DC
› Display of 250 event and 30 Trip records
- Protection Class CT
#
› 128*64 graphical display
M.R.P. (`)
Motor Protection Relay Model Aux. Supply (V) Communication Cat. No.
Per Unit
20 - 60V DC Non-Communicable NRVPR2A2ANX 33040
› MPR21 – 37, 46, 48, 49, 50BF, 50, 51, 50N, 51N, 51LR, 64, 66, 74TCS. numrAL
VPR21 85 - 265V AC,
› Microcontroller-based design Non-Communicable NRVPR2B2ANX 33040
87 - 265V DC
› Draw-out enclosure.
› CT rating#- 1A/ 5A (site selectable) R
› Display of 250 event and 30 Trip records 415VAC, Y
3 Phase,
› 128*64 graphical display 4 Wire B
› Modbus RS-485 Communication N
› Front Micro USB port for numrAL Suite
B
Y
Aux. Supply (V) M.R.P. (`) VPR21
Model Communication Cat. No.
Per Unit R
N
20 - 60V DC Modbus RS 485 NRMPR2A28RA 69000
numrAL
MPR21 85 - 265V AC,
Modbus RS 485 NRMPR2B28RA 69000
87 - 265V DC
# R
- Protection Class CT Y
B
R R
3 Phase,
3 Wire Y Y
B B
B
/110V PT
Y
VPR21
R
N
Lauritz Knudsen, 15.08.2026 99PDF page 107 numrAL – Numerical Protection Relays with Draw-out enclosure [8536]
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numrAL – Numerical Protection Relays with Draw-out enclosure [8536]
Restricted Earth Fault Relay Neutral Displacement Relay
REF11 - Restricted Earth Fault Relay (87N/64REF) NDR11 - Neutral Displacement Relay (59N)
› Microcontroller-based design › Microcontroller-based design
› Draw-out Enclosure › Draw-out Enclosure
› CT rating - 1A/ 5A (site selectable)
$
› Single Phase OV Protection
› Single Phase high impedance Earth Fault › Definite & Normal inverse time delay
› Instantaneous and definite time delay › Display of Actual value and 5 Trip records
[50 msec to 1 sec (programmable)]
› Built in third harmonic filter Model Aux. Supply (V) Communication Cat. No.
M.R.P. (`)
Per Unit
› Display of Actual value and 5 Trip records
20 - 60V DC Non-communicable NRNDR1A11NX 21560
Aux. Supply (V) M.R.P. (`) 85 - 265V AC,
Model Communication Cat. No. Non-communicable NRNDR1B11NX 21560
Per Unit 87 - 265V DC
numrAL
20 - 60V DC Non-communicable NRREF1A10NX 21560 NDR11 20 - 60V DC Modbus RS 485 NRNDR1A11RA 26400
85 - 265V AC, 85 - 265V AC,
Non-communicable NRREF1B10NX 21560 Modbus RS 485 NRNDR1B11RA 26400
numrAL 87 - 265V DC 87 - 265V DC
REF11 20 - 60V DC Modbus RS 485 NRREF1A10RA 26400
85 - 265V AC,
Modbus RS 485 NRREF1B10RA 26400
87 - 265V DC
- PS Class CT
$
Transformer / Generator Restricted Earth Fault Protection
PS Class CT PS Class CT
$ $
Broken Delta PT
NDR11
Trip Circuit Supervision Relay
TCS11 – Trip Circuit Supervision Relay (74)
Single Pole Over Current OR Earth Fault Relay › Microcontroller-based design
› Draw-out Enclosure
OCR11 – Single pole Over Current or Earth Fault Relay
› Monitors Trip Coil in Breaker ON & OFF condition
(50, 51 OR 50N, 51N)
› Site selectable Trip Coil Voltage
› Microcontroller-based design
› Draw-out Enclosure M.R.P. (`)
Model Aux. Supply (V) Communication Cat. No.
› Single Phase OC/ EF Protection Per Unit
› CT rating# - 1A/ 5A (site selectable) 20 - 60V DC Non-Communicable NRTCS1A13NX 12880
numrAL
TCS11* 85 - 265V AC,
› Inverse and definite time delay Non-Communicable NRTCS1B13NX 12880
87 - 265V DC
› Display of Actual Current value and 5 Trip records
*Available on Request - Please contact our nearest branch for details
Aux. Supply (V) M.R.P. (`)
Model Communication Cat. No.
Per Unit
20 - 60V DC Non-communicable NROCR1A10NX 21560
PT Fuse Failure Relay
85 - 265V AC,
Non-communicable NROCR1B10NX 21560
numrAL 87 - 265V DC PTF11 – PT Fuse Failure Relay (PTFF/97)
OCR11 20 - 60V DC Modbus RS 485 NROCR1A10RA 26400 › Microcontroller-based design
85 - 265V AC, › Draw-out Enclosure
Modbus RS 485 NROCR1B10RA 26400
87 - 265V DC
› Monitors the healthiness of PT Fuse.
#
- Protection Class CT › 3 Separate sensing elements.
Aux. Supply (V) M.R.P. (`)
Model Communication Cat. No.
Per Unit
20 - 60V DC Non-Communicable NRPTF1A14NX 12880
numrAL
PTF11* 85 - 265V AC,
Non-Communicable NRPTF1B14NX 12880
OCR11 OCR11 OCR11 OCR11
87 - 265V DC
Earth Fault Standby Earth Earth Fault Single Phase Over Current *Available on Request - Please contact our nearest branch for details
Protection Fault Protection Protection Protection - 50, 51
50N, 51N 50N, 51N
Lauritz Knudsen, 15.08.2026 100PDF page 108 Illustrated catalog page
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PDF page 109 Protection Relays [8536]
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Protection Relays [8536]
Reverse Power Relay
RPR11 – Reverse Power Relay (32)
› Microcontroller-based design
› Draw-out Enclosure
› Site selectable System Voltage - 110V / 415VAC
Aux. Supply (V) M.R.P. (`)
Model Communication Cat. No.
Per Unit
numrAL 20 - 60V DC Modbus RS 485 NRRPR1A12RA *
RPR11* 85 - 265V AC, 87 - 265V DC Modbus RS 485 NRRPR1B12RA *
*Available on Request - Please contact our nearest branch for details
Insulation Monitoring Relay New
Application: Monitoring of insulation resistance between Live conductors and Earth (Ground) in case of Unearthed (IT) electrical systems.
Detection of insulation faults at earlier stage prevents electrical hazards such as electric shock, fire and equipment damage.
Features: Application Segments:
› Threshold resistance setting from 1K to 100K ohm 1.Railways
› Suitable for 1Phase and 3 Phase (Both 3W and 4W) 2.Hospitals and Pharma
› Test/Reset function with remote and manual facility 3.Data Centre
› Indication of Power ON, Relay output and Fault. 4.Mining
› Both fail safe and non-failsafe relay option available
M.R.P. (`)
Description Cat Code
Per Unit
System voltage up to 520V.
IMR520 13260
Adjustable from 1-100K Ω with 2C/O
Single Element Lockout Relay - LocR
Features
› Lockout Relays [Master Trip Relay] - LocR
› Designed to operate the circuit breaker trip coils at high speed
› Available with Hand reset contact (HRC) and hand reset Flag (HRF)
Description Output contacts Reset Contacts Reset Flag Coil Voltage Cat. No. M.R.P. (`) Per Unit
24VDC L1H32DC024X 6000
110VDC L1H32DC110X 6000
Single element
3NO + 2NC Hand Hand 220VDC L1H32DC220X 6000
Lockout relay
110VAC L1H32AC110X 6000
230VAC L1H32AC230X 6000
ANSI Code - 86
Three Element Auxiliary Relay - AuxR
Features
› AuxR relay provides additional contacts for interlocking, control and signal applications
› Available with hand reset or self-reset contacts and hand reset Flag
Description Output Contacts Reset Contacts Reset Flag Coil Voltage Cat. No. M.R.P. (`) Per Unit
24VDC A3H40DC024X 12000
110VDC A3H40DC110X 12000
Three element
4 N/O Hand Hand 220VDC A3H40DC220X 12000
Auxiliary relay
110VAC A3H40AC110X 12000
230VAC A3H40AC230X 12000
24VDC A3A22DC024X 12000
110VDC A3A22DC110X 12000
Three element
2 N/O + 2 N/C Auto Hand 220VDC A3A22DC220X 12000
Auxiliary relay
110VAC A3A22AC110X 12000
230VAC A3A22AC230X 12000
Lauritz Knudsen, 15.08.2026 102No matching text found. Try a shorter model code or check the original PDF, including illustrated pages.
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