TM-DC Thermal-Magnetic Trip Unit for 2P Circuit Breakers from 630 A to 1200 A

Introduction

The TM-DC thermal-magnetic trip unit for 2P circuit breakers from 630 A to 1200 A are built-in trip units.

They are designed for DC general-purpose applications.

The TM-DC 2P trip units provide:

• adjustable thermal threshold

• adjustable magnetic pick-up

Description

The setting range and adjustment dials are on the front of the trip unit.

A Setting range for TM-DC thermal-magnetic 2P trip unit

B Adjustment dial for the thermal protection pick-up Ir

C Adjustment dial for the magnetic protection pick-up Ii

Setting the Thermal Protection

The thermal protection pick-up Ir is set by a 4-setting dial.

Turning the thermal protection adjustment dial (A) modifies the trip curve as shown (B).

The following table shows the values of the pick-up Ir (in amperes) for thermal protection (values indicated on the dial) with respect to every trip unit rating, relative to the position of the dial Ir.

Trip Unit Rating In (A) at 40 °C (104 °F)
630	800	1000	1200
Pick-up Ir (A) at 40 °C (104 °F)
441	560	700	840
504	640	800	960
567	720	900	1080
630	800	1000	1200

Setting the Magnetic Protection

The magnetic protection pick-up cannot be adjusted and equals the value shown below: