This document describes the features and characteristics of the Il 41-181.2 l cM phase balance current relay produced by ABB, including the relay structure, contact type, and the working principle of the indicating contactor switch.
This manual describes the ABB CM Phase Balance Current Relay, a device used to detect unbalanced currents in three‑phase systems. It explains the mechanical and electrical characteristics of both the non‑tapped and tapped versions of the relay.
The document includes detailed procedures for installation, setting adjustments, acceptance checks, calibration, routine maintenance, and part replacement. It also contains wiring diagrams, internal and external schematics, and specifications such as pickup currents, contact ratings, and timing curves.
| Minimum pickup current (non‑tapped) | 1 A |
|---|---|
| Continuous thermal rating | 7 A |
| Main contact rating | 30 A at 250 V DC |
| Contact gap (DC) | 0.047 in |
| Contact gap (AC) | 3/32 in |
The non‑tapped CM relay has a minimum pickup current of 1 ampere.
All relays should be inspected periodically and the time of operation should be checked at least once every year.
The main contacts will safely close 30 amperes at 250 volts DC.
All tap screws should be torqued to between 5.5 and 7.9 in‑lbs.