LJ Relay Comparison Guide

Compare the LJ high speed auxiliary relay to relays like the ABB AR, Alstrom Prima, Alstrom MJAV and GE SBA series relays. The LJ relay offers one of the fastest operating speeds and the highest inertia auxiliary relay immune to electrical transient and immune to mechanical shock miss-operations. The LJ relay is made in the USA.  For complete technical details, click here.

Available Contacts 2, 6, 10 4 5, 10, 20 4
Operating Voltage 48, 125, 250 VDC 48, 125, 250 VDC 24, 30, 48, 110, 220 VDC 24, 30, 48, 110, 220 VDC/VAC
Operating Time 4 msec for 6 contact model
5msec for 10 contact model
4 msec for 4 contact
(high threshold) model
8 msec for 5 & 10 contact
model 10msec for 20 contact model
Contact Current Carry Rating Continuous= 5 Amps DC
Short Time= 30 Amps
Continuous= 3 Amps DC
Short Time= ?
Continuous= 5 Amps DC
Short Time= 30 Amps
Continuous= 10 Amps DC
Short Time= 30 Amps
Contact Current Interrupt Rating Resistive= 1.1 Amps @ 125VDC Resistive= 0.5 Amps @ 125VDC Resistive= 0.64 Amps @ 125VDC Resistive= 0.96 Amps @   125VDC  W/Magnetic blow out= 2.8 Amps
Estimated Delivery 3-4 weeks 3-4 weeks 16-18 weeks 16-18 weeks


Technical Overview

The LJ relay is a family of  high speed auxiliary relays used in protective relay schemes for ultra-fast tripping of circuit breakers. The relay is also used to provide isolation of primary and back up relays. The LJ relay has the fastest operating speeds for the number of available contacts. Other relays like the PRIMA relay is more of a general purpose control relay due to its slower speed and time delayed operation/reset options. The PRIMA relay with magnetic blow-out contacts have a greater current (resistive & inductive) interrupting rating than the LJ relay. However, when used for tripping circuit breakers this is typically not an issue since 52a contacts interrupt the trip coil current and not the LJ relay trip contact.  The LJ and AR relays have optional test switches that isolate relay coil and contact output circuitry.  Alstom relays have no test switches.

The LJ relay family offer a  broad variety of flush and projection mounting styles in dustproof, aluminum cases. The LJ relay offers the highest inertia auxiliary relay – making it immune to electrical transient and mechanical shock miss-operations. Made in the USA, the LJ relays normally delivery in 3 to 4 weeks upon receipt of order, not months as is the case with several brands.


ContactUs GetAQuote