TM-DC EP Thermal-Magnetic Trip Unit for 4P Circuit Breakers for 1500 Vdc Applications
Introduction
The TM-DC EP thermal-magnetic trip unit for 4P circuit breakers from 100 A to 500 A are built-in trip units.
They are designed for DC photovoltaic and marine applications.
The TM-DC EP 4P trip units provide:
-
adjustable thermal threshold
-
fixed magnetic pick-up on trip units with In from 100 A to 250 A
-
adjustable magnetic pick-up on trip units with In from 250 A to 500 A
Description
The setting range and adjustment dials are on the front of the trip unit.
A Setting range for TM-DC EP thermal-magnetic trip unit
B Adjustment dial for the thermal protection pick-up Ir
C Adjustment dial for the magnetic protection pick-up Ii (on trip units with In from 250 A to 500 A only)
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 50 °C (122 °F) |
||||||||
|---|---|---|---|---|---|---|---|---|
| 250 A frame | 500 A frame | |||||||
|
100 |
125 |
160 |
200 |
250 |
250 |
320 |
400 |
500 |
|
Pick-up Ir (A) at 50 °C (122 °F) |
||||||||
|
70 |
87 |
112 |
140 |
175 |
175 |
224 |
280 |
350 |
|
80 |
100 |
128 |
160 |
200 |
200 |
256 |
320 |
400 |
|
90 |
112 |
144 |
180 |
225 |
225 |
288 |
360 |
450 |
|
100 |
125 |
160 |
200 |
250 |
250 |
320 |
400 |
500 |
The thermal protection setting is fixed at the trip unit rating.
Setting the Magnetic Protection on Trip Units With In from 100 A to 250 A
For trip units rated below 250 A, the magnetic protection pick-up cannot be adjusted and equals the value shown below:
|
Trip Unit Rating In (A) |
|||||
|---|---|---|---|---|---|
|
100 |
125 |
160 |
200 |
250 |
|
|
Fixed Pick-up Ii (A) +/– 20% |
|||||
|
DC value |
600 |
750 |
960 |
1,200 |
1,500 |
Setting the Magnetic Protection on Trip Units With In from 250 A to 500 A
For trip units rated between 250 A and 500 A, the magnetic protection pick-up Ii is set by a 6-setting dial.
Turning the magnetic protection adjustment dial (A) modifies the trip curve as shown (B).
The following table shows the values of the pick-up Ii (in amperes) for magnetic protection (values indicated on the dial), relative to the position of the Ii dial:
|
Trip Unit Rating In (A) |
|||
|---|---|---|---|
|
250 |
320 |
400 |
500 |
|
Pick-up Ii (A) +/– 20% |
|||
|
1,250 |
1,600 |
2,000 |
2,500 |
|
1,500 |
1,920 |
2,400 |
3,000 |
|
1,750 |
2,240 |
2,800 |
3,500 |
|
2,000 |
2,560 |
3,200 |
4,000 |
|
2,250 |
2,880 |
3,600 |
4,500 |
|
2,500 |
3,200 |
4,000 |
5,000 |