Basler Electric BE1-11m - Manual (Page 538)

526 9424200996 Rev L
Figure 350. Protection, Thermal, Resistance Temperature Detector (49RTD-1) Screen
Set the 49RTD-2 protection element as shown in Figure 351 to protect the motor bearings. The maximum
bearing temperature of 95
°C is supplied in the motor manufacturer data. Voting is set to 1, which provides
a sensitive bearing overtemperature trip. Only one RTD must be 95
°C or higher to result in a trip.
Figure 351. Protection, Thermal, Resistance Temperature Detector (49RTD-2) Screen
Protection - Current
Five instantaneous overcurrent elements, one current differential element, and one instantaneous
undercurrent element are used in this settings example.
Instantaneous Overcurrent (50-1) - Short-Circuit Protection
The 50-1 protection element is used to protect the motor stator windings for a short circuit. The pickup is
set as low as possible without causing a trip to occur during motor starting. The pickup setting is derived
using a dc offset of 1.7, 125 percent of LRA, and a BE1-11m pickup tolerance of 2 percent. Reference the
secondary FLA (Equation 38) and LRA (Max Locked Rotor Current) of 600% per motor manufacturer
data. See Equation 43.
𝑃𝑖𝑐𝑘𝑢𝑝 = 1.7 𝐷𝐶 𝑂𝑓𝑓𝑠𝑒𝑡 ∙ (125% 𝑜𝑓 𝐿𝑅𝐴 + 2% 𝑃𝑖𝑐𝑘𝑢𝑝 𝑇𝑜𝑙𝑒𝑟𝑎𝑛𝑐𝑒) ∙ �𝐿𝑅𝐶 (600%) ∙ 𝐹𝐿𝐴
𝑆𝑒𝑐𝑜𝑛𝑑𝑎𝑟𝑦
�
= 1.7 ∙ (1.25 + 0.02) ∙ (6 ∙ 4.54) = 71.77 𝐴
Equation 43. 50-1 Pickup
Select three-phase mode and set the Pickup setting to 71.77 A as shown in Figure 352.
Settings Calculation Examples BE1-11m