TM-D Thermal-Magnetic Trip Unit for 3P and 4P Circuit Breakers up to 63 A
Introduction
TM-D thermal-magnetic trip units for 3P/4P circuit breakers up to 63 A are interchangeable trip units.
They are designed for AC and DC general-purpose applications.
The TM-D interchangeable 3P/4P trip units provide:
-
adjustable thermal threshold
-
fixed magnetic pickup
Description
Setting the Thermal Protection
The thermal protection pickup 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 pickup 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) |
16 |
25 |
32 |
40 |
50 |
63 |
|---|---|---|---|---|---|---|
|
Pickup Ir (A) at 40 °C (104 °F) |
11 |
18 |
22 |
28 |
35 |
44 |
|
13 |
20 |
26 |
32 |
40 |
50 |
|
|
14 |
23 |
29 |
36 |
45 |
57 |
|
|
16 |
25 |
32 |
40 |
50 |
63 |
Setting the Magnetic Protection
The magnetic protection pickup Ii cannot be adjusted and equals the value shown below:
|
Trip unit rating In (A) |
16 |
25 |
32 |
40 |
50 |
63 |
|
|---|---|---|---|---|---|---|---|
|
Fixed pickup Ii (A) +/– 20% |
DC value |
260 |
400 |
550 |
700 |
700 |
700 |