GE Industrial Solutions Entellisys 4.0 System User Manual - Manual (Page 56)

Single point functions 56
5
The Entellisys system provides four long time delay band settings. This selection defines the
value of the constant K in the LT equation.
The following long time delay band selections are available:
•
Band 1: K = 108 seconds
•
Band 2: K = 216 seconds
•
Band 3: K = 432 seconds
•
Band 4: K = 900 seconds
The fixed LT Overcurrent Protection delay setting at the Messenger is Band 4 (K = 900 s).
5.1.1.1 Accuracy
Pickup accuracy is ± 10% over the entire protection range.
5.1.1.2 Setup
The LT Pickup setting is set with a rotary switch at the Messenger. This setting applies to the LT
protection provided by the Messenger and the protection provided by the Entellisys CPU. The
positions of the rotary switch and LT Pickup settings are shown in Table 5-1.
The delay for the LT protection provided by the Messenger is not user-programmable; it is fixed
according to the safe operating region for the circuit breaker controlled by the given Messenger.
The delay for the LT protection provided by the Entellisys CPU is set in the HMI as shown in
Figure 5-1.
Table 5-1 Rotary switch positions and LT pickup settings
Position 0 1 2 3 4 5 6 7 8 9 A B C D E F
Setting 1.1 0.5 0.5 0.5 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1.0 1.05