Varistors
Integrated self-protection against fire hazards
November 9, 2010
TDK-EPC, a group company of the TDK Corporation, presents a new series of EPCOS
ThermoFuse varistors (ETFV) that are protected from overload and thus prevent fires. The
ETFV series consists of a disk varistor of the AdvanceD series connected in series with a
thermally coupled fuse and integrated in a package. The thermo-fuse encapsulated in a
special plastic disconnects an overheated varistor from the power circuit and thus prevents
the flames and smoke from developing. This increases the reliability of the equipment to be
protected. Thanks to their thermal resistance and flame-retarding design, ThermoFuse
varistors satisfy the specifications of UL 94 V-0. They are also qualified to UL 1449 3rd
Edition, UL 60691 and IEC 6 0950-1 Annex Q.
In addition to the two terminal wires for the varistor, the EPCOS ETFV series has a third
terminal that may be used to send warning signals – for example, to an LED to indicate that
the fuse has been activated.
The product range comprises disks with diameters of 14, 20 or 25 mm including the package.
TDK-EPC is one of the few manufacturers worldwide to offer a ThermoFuse varistor with a
25-mm disk. The ETFV variants are designed to absorb maximum surge currents with an
8/20 µs pulse of between 6 and 20 kA at rated voltages of between 130 and 420 VRMS. They
have a surge current capability of 20,000 A and a maximum energy absorption capacity of
700 J for 2 ms.
Applications for ETFV include household appliances, power supplies, inverters for solar
installations, and drives. They are also used for the general protection of electrical wiring and
installations.
----Glossary
 Varistor: voltage-dependent resistor (VDR) have a high resistance in their normal state. Only when
a specific voltage is attained or exceeded do they suddenly become conductive. Thanks to this
characteristic, they are well suited for overvoltage protection applications.
Main applications
 Overvoltage protection of household appliances, power supplies, inverters for solar installations,
and drives, as well as the general protection of electrical wiring and installations.
TDK-EPC Corporation
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Main features and benefits
 Integrated fuse for protection against fire and smoke formation
 Specified to UL 94 V-0, UL 1449 3rd Edition, UL 60691 and IEC 6 0950-1 Annex Q
 High surge current capability of between 6 and 20 kA (8/20 µs)
----About TDK-EPC Corporation
TDK-EPC Corporation (TDK-EPC), a TDK group company, is a leading manufacturer of electronic
components, modules and systems headquartered in Tokyo, Japan. TDK-EPC has emerged from the
combination of the electronic components business of TDK and the EPCOS Group and markets its
products under the product brands, TDK and EPCOS.
The product portfolio includes ceramic, aluminum electrolytic and film capacitors, ferrites and inductors, high-frequency components such as surface acoustic wave (SAW) filter products and modules,
piezo and protection components, and sensors. With this product spectrum TDK-EPC offers a broad
range of products and solutions of outstanding value from a single source and focuses on demanding
markets in the areas of information and communication technology and automotive, industrial and
consumer electronics. The company has design and manufacturing locations and sales offices in Asia,
Europe, and in North and South America.
----You can download this text and associated images from www.epcos.com/pressreleases.
Further information on the products can be found under www.epcos.com/varistors_thermofuse.
Please forward reader inquiries to marketing.communications@epcos.com.
----Contacts for regional media
Region
Contact
Phone
Mail
+65 6845-7923
angelia.liew@epcos.com
ASEAN
Ms. A. LIEW
EPCOS PTE LTD
SINGAPORE
Greater
China
Ms. S. SUEN
EPCOS LTD
HONG KONG
+852 3669-8224
stella.suen@epcos.com
Europe
Mr. C. JEHLE
EPCOS
Munich/ GERMANY
+49 89 636-24 615
christoph.jehle@epcos.com
India
Mr. D. SAWANT
EPCOS India Private Ltd.
Mumbai/ INDIA
+91 22 4256 0601
deepak.sawant@epcos.com
North
America
Ms. S. McSHEA
EPCOS Inc.
Greenville, SC/ USA
+1 864 232-4240
mcsheacp4@aol.com
South
America
Mr. C. DALL’AGNOL
EPCOS do Brasil Ltda.
São Paulo/ BRAZIL
+55 11 3817-3435
candido.dallagnol@epcos.com
TDK-EPC Corporation
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