DT3000
Instruction Leaflet
I.B. 17555D
Effective: Date 07/02
Page 25
For more information visit:
www.cutler-hammer.eaton.com
Supersedes I.B. 17555C dated November 1999
Characteristic Curve Reminders
As previously mentioned, combining protective capabilities
is a matter of coordination. The effects of one selection
should always be evaluated against other selections to
determine if the overall desired result is obtained. For this
reason, keep in mind the following Digitrip 3000 selection
possibilities and relay design features when programming
the unit to closely coordinate with system protective needs:
1. When “NONE” is selected as a setting, the associated
tripping function is disabled.
2. When “NONE” is selected for the Phase
Instantaneous Setting, a Phase Discriminator option is
offered.
3. The internal design of the Digitrip 3000 Protective
Relay is such that the Short Delay Time setting might
take precedence over the Inverse Time Overcurrent
Time.
Fig. 3-4 Typical Inverse Time Overcurrent Pickup
Horizontal Movement
Fig. 3-5 Typical Time Multiplier Adjustment (I
2
T
Response)
Fig. 3-6 Short Delay Setting Adjustment
Fig. 3-7 Short Delay Time Adjustment
Minimum
Pickup Setting
Time Multiplier is
represented by the
dotted portion of
the curve.
Short Time Pickup
is represented by
the dotted portion
of the curve
.
Short Delay Time
is represented by
the dotted portion
of the curve.
