Seepex BN 5-12 Series, Operation & Maintenance Manual

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Manual of Electric Motors 89
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The alarm temperature limits and thermal protection shutdowns can be defined according to the application;
however these temperature limits can not exceed the values in Table 6.4.
Table 6.4 - Maximum activation temperature of the thermal protections
Component Insulation class
Maximum temperature of the protection setting (°C)
Alarm Tripping
Winding
B - 130
F 130 155
H 155 180
Bearing All 110 120
Notes :
1) The number and type of the installed protection devices are stated on the accessory nameplate of the motor.
2) If the motor is supplied with calibrated resistance, (for example, Pt-100), the motor protection system must be set according to the
operating temperatures indicated in Table 6.4.
6.11. RESISTANCE TEMPERATURE DETECTORS (PT-100)
The thermocouples Pt-100 are made of materials, whose resistance depends on the temperature variation,
intrinsic property of some materials (usually platinum, nickel or copper), calibrated resistance. Its operation is
based on the principle that the electric resistance of a metallic conductor varies linearly with the temperature,
thus allowing a continuous monitoring of the motor warm-up through the controller display ensuring a high level
of precision and answer stability. These devices are widely used for measuring temperatures in various industry
sectors.
In general these devices are used in installations where precise temperature control is required, for example, in
installation for irregular or intermittent duty.
The same detector may be used for alarm and tripping purposes.
Table 6.5 and Figure 6.16 show the equivalence between the Pt-100 resistance and the temperature.
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