U.S. Ground
Parcel Shipments
See Shipping Policy

Protection Relays

Protection relays are essentially monitoring devices that keep a watchful eye over the electrical circuits and equipment, such as transformers, generators, and transmission lines. They detect abnormal conditions, like short-circuits or overloads, and take necessary actions to mitigate these problems. The primary action typically involves sending a signal to breakers to disconnect the faulty section from the rest of the system. This action prevents further damage, possible blackouts, or safety hazards.

The principle behind the operation of relays is based on the measurement of electrical quantities like current, voltage, frequency, and sometimes temperature. Depending on these measurements, a relay can determine whether the system is operating within safe parameters or not.

There are different types of protection relays, and they can be categorized based on their function, construction, or operating mechanism. For instance, there are distance relays that operate depending on the impedance between the relay location and the fault point, differential relays that function by comparing the difference between input and output electrical quantities, and overcurrent relays that respond to excessive currents.

Products

Sort By:
Littelfuse MP8010 MOTOR OVERLOAD PROTECTION 8000
Littelfuse MP8010 MOTOR OVERLOAD PROTECTION 8000
$869.93 $1558.64
Littelfuse MP8010 MP8000 Series - Bluetooth Overload Relay Series - Littelfuse MP8000 Relays Provide Exceptional Motor Protection
Littelfuse SE-135-XGC-10 GF-GC MON, DC SUPPLY, EXT-GC
Littelfuse SE-135-XGC-10 GF-GC MON, DC SUPPLY, EXT-GC
$5739.81 $10284.07
Littelfuse SE-135-XGC-10 GF-GC MON, DC SUPPLY, EXT-GC
Littelfuse SE-135-XGC-03 GFGC MON, AC/DC SUPPLY, EXT-GC, ETHERNET
Littelfuse SE-135-XGC-03 GFGC MON, AC/DC SUPPLY, EXT-GC, ETHERNET
$7425.30 $13303.98
Littelfuse SE-135-XGC-03 GFGC MON, AC/DC SUPPLY, EXT-GC, ETHERNET
Littelfuse SE-135-XGC-00 GROUND-FAULT GROUND CHECK RELAY EXT-GC
Littelfuse SE-135-XGC-00 GROUND-FAULT GROUND CHECK RELAY EXT-GC
$4783.17 $8570.06
Littelfuse SE-135-XGC-00 GROUND-FAULT GROUND CHECK RELAY EXT-GC
Littelfuse AF0100-00-CC ARC-FLASH RELAY UNIV W/CONFORMAL COAT
Littelfuse AF0100-00-CC ARC-FLASH RELAY UNIV W/CONFORMAL COAT
$1852.94 $3319.93
Littelfuse AF0100-00-CC ARC-FLASH RELAY UNIV W/CONFORMAL COAT
Littelfuse AF0100-10-CC ARC-FLASH RELAY 24VDC W/CONFORMAL COAT
Littelfuse AF0100-10-CC ARC-FLASH RELAY 24VDC W/CONFORMAL COAT
$1852.94 $3319.93
Littelfuse AF0100-10-CC ARC-FLASH RELAY 24VDC W/CONFORMAL COAT
Littelfuse AF0025-00 SIMPLIFIED ARC-FLASH RELAY
Littelfuse AF0025-00 SIMPLIFIED ARC-FLASH RELAY
$705.82 $1264.62
Littelfuse AF0025-00 SIMPLIFIED ARC-FLASH RELAY
ABB TF96-87 - Thermal Overload Relay 75 ... 87 A
ABB TF96-87 - Thermal Overload Relay 75 ... 87 A
$147.34 $255.54
ABB TF96-87 - The TF96-87 thermal overload relay is an economic electromechanical protection device for the main circuit. It offers reliable and fast protection for motors in the event of overload or phase failure. The device has trip class 10. Further features are the temperature compensation, trip contact (NC),... Show More
ABB TF96-68 - Thermal Overload Relay 57 ... 68 A
ABB TF96-68 - Thermal Overload Relay 57 ... 68 A
$125.67 $217.96
ABB TF96-68 - The TF96-68 thermal overload relay is an economic electromechanical protection device for the main circuit. It offers reliable and fast protection for motors in the event of overload or phase failure. The device has trip class 10. Further features are the temperature compensation, trip contact (NC),... Show More
ABB TF96-60 - Thermal Overload Relay 48 ... 60 A
ABB TF96-60 - Thermal Overload Relay 48 ... 60 A
$125.67 $217.96
ABB TF96-60 - The TF96-60 thermal overload relay is an economic electromechanical protection device for the main circuit. It offers reliable and fast protection for motors in the event of overload or phase failure. The device has trip class 10. Further features are the temperature compensation, trip contact (NC),... Show More
ABB TF96-51 - Thermal Overload Relay 40 ... 51 A
ABB TF96-51 - Thermal Overload Relay 40 ... 51 A
$125.67 $217.96
ABB TF96-51 - The TF96-51 thermal overload relay is an economic electromechanical protection device for the main circuit. It offers reliable and fast protection for motors in the event of overload or phase failure. The device has trip class 10. Further features are the temperature compensation, trip contact (NC),... Show More
ABB TF96-96 - Thermal Overload Relay 84 ... 96 A
ABB TF96-96 - Thermal Overload Relay 84 ... 96 A
$147.34 $255.54
ABB TF96-96 - The TF96-96 thermal overload relay is an economic electromechanical protection device for the main circuit. It offers reliable and fast protection for motors in the event of overload or phase failure. The device has trip class 10. Further features are the temperature compensation, trip contact (NC),... Show More