Toshiba 18 - 1250 A Instruction Manual page 55

TE Series
WARNING
THIS IS NOT INTENDED TO BE USED AS "PERSONNEL PROTECTION" GROUND FAULT!
This feature is only intended to provide a level of equipment protection against damaging
ground currents. Ground faults are potentially dangerous conditions and must be
corrected immediately for safety of operating personnel.
Digital Solid State Soft Starters 18 – 1250A
5.6.8.a Ground Fault
F046 – F047 provides Ground Fault protection for equipment only
(a.k.a. Arcing Ground Fault) using the Residual Current method.
Trip settings are based on the CT ratio as shown in F074 (see
below). A delay time is available in F047 to help prevent nuisance
trips. Ground current can always be viewed in the Status Display,
shown with a "G" prefix (see section 5.3.1).
F046 = Ground Fault Trip
Factory Setting = 0 (Disabled)
Range = 5 - 90% of CT value, or 0 (Disabled)
When a value other than 0 is entered for F046, the starter will
trip if current to ground exceeds this percentage of the unit CT
value. The CT value is shown in F074 (see section 5.6.12). This
value is different from the Unit Rating or FLA setting. To
calculate actual ground current, multiply the CT value of F074
by the setting of F046.
Example:
210A starter, desired Ground Fault Trip level is 20A:
On this unit, the CT value reading from F074 will be 250 (250:5)
20 / 250 = 0.08 (8%)
Set F046 to 8
F047 = Ground Fault Trip Delay
Factory Setting = 2 seconds
Range = 1 - 60 seconds
Provides a time delay to prevent nuisance trips from short-
duration transients. Using default setting, if the Ground Fault
current exceeds the level set in F046 for more than 2 seconds,
the starter will trip.
CAUTION
This method of Ground Fault sensing may not provide adequate
equipment protection in resistance-grounded systems. We
recommend providing external GF protection using a core
balanced Zero Sequence CT for those types of applications.
Consult factory for additional assistance.
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