Temperature Compensation; Phase Failure - Eaton ZB12 XTOB Series Manual

1.3.3 Temperature compensation

1.3.4 Phase failure

1 ZB12-.../XTOB...BC1 and ZB32-.../XTOB...CC1 overload relays
Table 4: Current ranges of ZB32-.../XTOB...CC1 relays
Type
ZB32-... XTOB...
ZB32-0,16 XTOBP16CC1
ZB32-0,24 XTOBP24CC1
ZB32-0,4 XTOBP40CC1
ZB32-0,6 XTOBP60CC1
ZB32-1,0 XTOB001CC1
ZB32-1,6 XTOB1P6CC1
ZB32-2,4 XTOB2P4CC1
ZB32-4 XTOB004CC1
ZB32-6 XTOB006CC1
ZB32-10 XTOB010CC1
ZB32-16 XTOB016CC1
ZB32-24 XTOB024CC1
ZB32-32 XTOB032CC1
ZB32-38 XTOB038CC1
Two parameters influence the deflection of the bimetallic releases. There is
for one the heat which is generated in proportion to the current flow, and
secondly, the influence of the ambient air temperature.
The influence of the ambient air temperature is automatically compensated
within a temperature range from -5 °C to +55 °C by means of an additional
current-free bimetallic release that continuously corrects the tripping range.
The ZB12-.../XTOB...BC1 and ZB32-.../XTOB...CC1 overload relays are
phase failure sensitive. The deflecting action of all three bimetallic releases is
directed towards a tripping bridge that switches over a snap-action switch
when the limit value is reached. At the same time, all three bimetallic
releases shift the differential bridge.
If the path of action of one of the bimetallic releases is reduced due to a
phase loss, the differential bridge is retarded and the distance is converted
into an additional tripping distance, which leads to an early tripping.
ZB12-..., ZB32-... 11/16 MN03407004Z-DE/EN www.eaton.com
Current range I
A
0.1 - 0.16
0.16 - 0.24
0.24 - 0.4
0.4 - 0.6
0.6 - 1.0
1.0 - 1.6
1.6 - 2.4
2.4 - 4.0
4.0 - 6.0
6.0 - 10
10 - 16
16 - 24
24 - 32
32 - 38
1.3 Description of device
31