Spotlight on Circuit Protection - Power Electronics

<strong>Spotlight</strong> on Circuit Protection
Surge-Protection Device Modules
Raycap’s Strikesorb 40-mm and
80-mm surge-protection device (SPD)
modules are now certified by Underwriters
Laboratories (UL) for meeting the UL
1449 3rd Edition Safety Standard. Featuring
a flat-slope resistance characteristic,
the Strikesorb SPD modules received a
nominal discharge current test rating of
20 kA, the highest possible, without the
use of internal fuses. The Strikesorb SPD
modules have been designated as Type-4
devices deemed suitable by UL for use in
Type-2 applications.
The 40-mm Strikesorb module is
rated at 140 kA, and the 80-mm Strikesorb
module is rated at 200 kA. The
modules have an operating voltage range
of 120 V to 600 V. The Strikesorb module
is comprised of a single distributiongrade
metal oxide varistor (MOV) disc
that provides uniform distribution of
the surge current over the total area
of the MOV protection element. The
Strikesorb’s monolithic design provides
®
a straight electrical path to its large single
disc of distribution-grade varistor material,
unlike other SPD systems that employ
arrays of commercial-grade MOV
components with 90-degree-angled lead
wires to each varistor. The absence of lead
wires and internal disconnect mechanisms
give the Strikesorb extremely
low let-through voltage. The Strikesorb
module also can be directly connected
on the power bus bars inside the cabinet
of the equipment after the main circuit
breaker.
Raycap
Liberty Lake, Wash.
www.raycapinc.com
CHECK OUR INVENTORY AT:
www.fusesunlimited.com
CALL: (800) 255-1919
The Circuit Protection Specialist
ISO 9001:2000 Registered
ESD TVS Diodes
OnChip Devices’ ESD2200 is a family
of miniature transient voltage suppressor
(TVS) diodes with very high protection
levels from electrostatic discharge
(ESD). The ESD2200 safely dissipates
ESD strikes of ±30-kV contact discharge.
It is offered in two, three, four and five
channels and has superior electrical
performance.
The input capacitance of the ESD2200
is under 20 pF. This diode capacitance
also provides some EMI filtering when
used in combination with a pc-board
trace or series resistor. Packaged in
miniature SOT23, SOT143 and SC70
(SMD), the OnChip ESD2200 is available
immediately. Pricing ranges from $0.06
each to $0.15 each.
OnChip Devices
Santa Clara, Calif.
www.onchip.com
SMD Fuse
Schurter has added several current
ratings to its UMT 250 series, for a total
of 22 ratings from 80 mA to 10 A. The
series is designed to provide overcurrent
and short-circuit protection in both primary
and secondary circuits.
The UMT 250 can be mounted on
both sides of the pc board. Its low profile
increases production rates when mounted
with pick-and-place assembly machines.
An ideal substitute for axial and
radial leaded through-hole fuses where
bending leads can cause assembly delays,
the UMT 250 is packaged in plastic bags
of 100 pieces or in 2000-piece taped reels
for automated assembly. Pricing starts at
$0.60 each in quantities of 100.
Schurter
Santa Rosa, Calif.
www.schurterinc.com/new_fuses
Fuse Selective Coordination Panel
The Ferraz Shawmut Fused Selective
Coordination Panel is a UL 67-listed
panel board that uses class CC ultrasafe
fuse holders with easy-to-see blownfuse
indicators. The compact size and
removable backpan allow for easier
installation.
Features of the panel include a bonded
ground bar and a neutral bar with
set-screw terminations. Main-lugs-only
terminations include an optional molded
case switch. Branch circuit breakers
provide circuit isolation, and the panel
Power Electronics Technology August 2008 42
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comes with a 100-A, 200-A or 300-A
copper main bus. The panels accommodate
12 to 42 circuits.
Ferraz Shawmut
Newburyport, Mass.
http://us.ferrazshawmut.com
Inrush Current Limiter
With a high-temperature construction
that allows safe operation at high
continuous currents, Ametherm’s
MegaSurge Series inrush current limiter
withstands up to 50 A of continuous current
and 960 J of input energy. The device
is offered in sizes ranging from 12 mm
to 35 mm with resistance values from
1 Ω to 220 Ω. Steady-state current values
are available from 2 A to 50 A. Target
applications include ac motors and
motor drives, X-ray equipment, power
supplies, universal power supplies and
welding equipment.
Ametherm
Carson City, Nev.
www.ametherm.com
Surge-Suppressor Guide
Circuit Components has developed a
surge-suppressor selection guide to help
customers narrow their search of surge
suppressors for their application needs.
The guide is a graphics page depicting
the category and the location within the
electrical network of the equipment to be
protected. Clicking on the user’s specific
equipment location and category will display
a list of available surge-suppressor
solutions. It serves as a general guide,
and final selection depends on specific
requirements.
Circuit Components
Tempe, Ariz.
www.surgecontrol.com
Radial Leaded Fuses
The RoHS-compliant Cooper
Bussmann SR-5, SS-5 and new SR-5H
Series of radial leaded fuses provides
cost-effective primary circuit protection
without sacrificing performance
in space-constrained power-supply
applications. The IEC designs have approvals
through 6.3 A, and UL designs
through 10 A. For applications requiring
fuse replacement, a radial fuse holder is
available.
The SR-5H Series and more SR-5
low-amp ratings (now 40 mA to 6.3 A)
expand an already diverse offering of
<strong>Spotlight</strong> on Circuit Protection
radial fuses that include fast-acting and
time-delay versions. The SR-5H Series
also provides protection up to 300 Vac
with an interrupting rating of 100 A. The
round SR-5 radial fuses offer equivalent
product performance to typical 5-mm
glass fuses with a 60% footprint reduction.
The rectangular SS-5 fuses offer an
additional 33% reduction to the SR-5
footprint.
Cooper Bussmann
Ellisville, Mo.
www.cooperbussmann.com
Tantalum Capacitors
AVX’s TAW Series of fused tantalum
capacitors features an internal fuse to
protect against short circuits and damaging
high dc leakage currents. Each
tantalum capacitor in this series will
remove itself from the circuit and into
fail-safe mode when the internal fuse
exceeds the current limit.
The lead-free, RoHS-compliant TAW
tantalum capacitor series provides capacitance
values up to 10 MΩ and low
ESR for high-reliability applications.
Manufactured using thin-film technology,
the TAW Series is priced starting at
$0.65 each in quantities of 10,000.
AVX
Myrtle Beach, S.C.
www.avx.com
PPTC Thermistors
From Littelfuse, the 0603L series
Polyfuse PPTC (polymer positive temperature
coefficient thermistor) is a
micro form-factor resettable overcurrent
protection device. The 0603L PPTC
series is available in four hold current/
maximum voltage ranges: 0.10 A/15
Vdc, 0.20 A/9 Vdc, 0.25 A/9 Vdc and
0.35 A/6 Vdc. The 0603-sized device has
a maximum fault current rating of 40 A
and is certified by both TUV and UL.
Littelfuse
Des Plaines, Ill.
www.littelfuse.com PETech
www.powerelectronics.com 43
Power Electronics Technology August 2008