GE 869 Instruction Manual page 365

CHAPTER 4: SETPOINTS
869 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
Figure 4-86: Volts-Per-Hertz Curves for Inverse Curve A
Inverse Curve B:
The curve for the Volts/Hertz Inverse Curve B shape is derived from the formula:
T
where: T = Operating Time
TDM = Time Delay Multiplier (delay in seconds)
V = fundamental RMS value of voltage (pu)
F = frequency of voltage signal (pu)
Pickup = volts-per-hertz pickup setpoint (pu)
The Volts/Hertz inverse B curves are shown below.
TDM V
when
F
V
1
Pickup
PROTECTION
Pickup
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