Figure 31: Definite Time Overcurrent Element - GE P24DM Technical Manual

Chapter 6 - Current Protection Functions
Time t
100 ms
40 ms
V00781

Figure 31: Definite time overcurrent element

Setting guidelines
To prevent operation during starting the instantaneous element is usually set to 1.25 times the maximum starting
current.
The timer setting is system dependent and can be set to a value in the region of 100 ms. A time delay setting of
less than 2 cycles duration is not realistic due to the fact that a minimum confirmation time, equivalent to two
cycle duration, is required before tripping.
Note:
If the motor is controlled by a fused contactor it needs to be coordinated with the fuse. This prevents the contactor attempting
to interrupt current in excess of its breaking capacity.
Setting example
Utilizing the previously specified motor parameters, set:
I>Current Set = (1.25 x 4.7 x 293)/300 = 5.7 In
I> Time Delay = 100 ms
100
1 x I>
1.13 x I>
P24xM
Current I
P4083ENb
P24xM-TM-EN-2.1