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POWER DISTRIBUTION & CONTROL EQUIPMENTS
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16-77
TRANQUELLTransient Voltage Surge Suppressor (or TVSS)(Metal
Enclosed HESPTM)
120 Through 575 Volt Ratings
TypicalApplicationsTo offer protection against either externally
induced surges caused by lightning orutility switching, or
internally generated switching surges caused by starting/stopping
of compressors, air conditioners, elevators, and machine tools or
fuse/circuit breaker operations.
Facility Protection: Service entrance switchgear and panels
feeding critical
equipment.
DataProcessing: Computers and UPS.
Communications: Telephones and Broadcasting.
IndustrialElectronics: Drives, Manufacturing Equipment and
Transportation.
MedicalElectronics: CAT scan, x-ray, NMR.
Utilities: Transient protection on service accounts.
Selection Guidelines-Select the proper HESPTM unit for your
system voltage,
configuration and the anticipated surge environment in terms of
energy capability.
MCOV - (Maximum Continuous Operating Voltage) defines the
maximum line to
line or line to neutral continuous voltage to be applied to the
protector. Iftemporary power frequency overvoltages in excess of
the MCOV are anticipated,check the TOV (Temporary Over Voltage)
capability of the device against systemconditions.
Energy Capability Options-The high energy capability option
permits
survivability in demanding environments and a lower clamping
level for betterprotection.
High Surge Current Capability-The 76mm HESP (TVSS) protective
elements
are designed to withstand up to 300kA (1) & (2).
Connection-Fused protectors (9L10F series) are supplied in an
indoor/outdoor
enclosure. To minimize lead lengths, terminal blocks are
provided inside theenclosure for incoming and outgoing connections
for each phase for conductorsizes of #6 AWG to 250kcmil. This
offers maximum protection under surgeconditions by reducing the
inductive voltage associated with lead length.
(1) Fuses are capable of withstanding up to 30 kA of 8 x 2011S
surge current. IfHESP sees higher than this limit of surge current,
you may experiencenuisance fuse blowing; check fuses and replace as
needed to reinstate theprotector.
(2) 300kA based on capability of 40mm disk to withstand 100kA.
Therefore,based on A/mm2, it can be concluded that the 76mm disk
withstands 300k4.
Each of the terminal blocks provided has two holes, one for Line
In and one forLoad Out. Each hole can handle a maximum of 250kcmil
cable (or 2-250kcmilcables per terminal block). This limit on cable
size will automatically limit thecontinuous load current that the
terminal block can see. The limited currentcarrying capability of
this cable size assures that the terminal blocks will not seeamp
ratings beyond 200 Amps per hole which is the limit.
Fused protectors are also suitable for an external T-connection
(parallel) with nolimitation on continuous load current.
If the unit is externally T connected, the cable must be brought
out of the HESP
box to a junction box in the line, using one cable (250kcmil
maximum) for eachphase plus ground (utilizing only one hole of the
terminal block), rather than usingthe terminal blocks for line and
load. The line leads must be kept as short as
possible to maintain clamping voltage levels.
Indoor/OutdoorEnclosure-NEMA 3R construction.
Diagnostics-Fast acting line isolation fuses are provided with
blown fuseindicating lights (one per pole). The fuses isolate a
potentially shorted device fromthe system which allows continued
system operation, without protection, until thedevice is evaluated.
The lights provide visual indication when protection
isdisabled.
Common Mode Protection Option-in addition to normal mode
protection (L-L
and L-N), HESP offers common mode protection (L-G and N-G) for
8-phase wyeand single-phase, 1 or 2 pole devices. This optional
protection is recommendedfor devices remotely located from the
system neutral to ground bond.
UL1449ListedDesigned and tested according to ANSI/IEEE C62.41
and C62.45.
TRANSIENT VOLTAGE SURGE SUPPRESSORS
