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Selector Chart For Fuses Resettable
Polymeric PTC
9E
NEW
ISO 9001 / ISO 14001
Fuses cross to competitive resettable devices. See our online cross list at http://www.schurterinc.com/cross.htm
Series Page Mounting terminals Hold current IH @ 23˚C PFMD 106 -108 surface mount 200mA to 1.1A PFSM 109 - 111 surface mount 300mA to 2.5A PFRA 112 -115 radial leaded 100mA to 9A PFRX 116 -118 radial leaded 1.1A to 3.75A PFST/PFLT 119 - 122 strap (standard or slotted) 1A to 4.2A
NonResettable
Surface Mount
NEW
EIA 1206 With or without fuse clips
NEW
Time-lag version OMT
New MSB / MKT Time lag versions
Series / Voltage Page Rated current Time/current action
MGA 125V 127 200mA to 5A quick-acting
SFP 63V; SFC 63V 128-129 1A-5A; 800mA-4A quick-acting
OMF 63V 130-131 63mA to 10A quick-acting
OMF 125 132-133 63mA to 10A quick-acting
OMF/OMT 125/250V 134 250mA to 4A
MELF/MKF 125V 135-136 125mA to 7A
quick-acting or time-lag quick-acting or time-lag
UL listed versions MSF-U & MST-U
Through-Hole
NEW NEW
NEW
With radial leads
Hermetically sealed
MXT with high breaking capacity
Series / Voltage Page Rated current Time/current action
MSA 125V 137 63mA to 15A quick-acting
MGL 125V 138 200mA to 5A quick-acting
MSF 125V 139 100mA to 5A quick-acting
MSF 250V 140 40mA to 5A quick-acting
MST/MXT 250V 141/142 50mA to 6.3A time-lag
FRT 250V 143 250mA to 6.3A quick-acting or time-lag
5 x 20mm
Series Page
SA/SP/SPT/FSM 144 -154
Quick-acting and time-lag characteristics available, with low, medium or high breaking capacities. Pigtail leads optional. FSF/FST/FTT/FSM All series Fuse kits for prototypes
144 - 154 144 - 154 156
Telecom
Surge-Tolerant for Telecom applications
Series / Voltage Page Rated current Time/current action
OSU 125V 162 250mA to 3.15A quick-acting
OSU / OMT 250V 162 250mA to 3.15A quick-acting
MSU 125V 163 250mA to 3.15A quick-acting
MSU 250V 163 250mA to 3.15A quick-acting
FRT 250V 164 250mA to 3.15A quick-acting
FSU / SSU 250V 165-166 250mA to 3.15A quick-acting
102
Schurter, Inc. • Phone 707-778-6311 • Fax 707-778-6401 • E-mail
[email protected] • Website http://www.schurterinc.com
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H O W P O LY M E R I C R E S E T TA B L E O V E R C U R R E N T P R O T E C TO R S W O R K
The conductive carbon black filler material in the polymeric device is dispersed in a polymer that has a crystalline structure. The crystalline structure densely packs the carbon particles into its crystalline boundary so they are close enough together to allow current to flow through the polymer insulator via these carbon Òchains.Ó When the conductive plastic material is at normal room temperature, there are numerous carbon chains forming conductive paths through the material. Under fault conditions, excessive current flows through the polymeric device. I2R heating causes the conductive plastic materialÕs temperature to rise. As this self heating continues, the materialÕs temperature continues to rise until it exceeds its phase transformation temperature. As the material passes through this phase transformation temperature, the densely packed crystalline polymer matrix changes to an amorphous structure. This phase change is accompanied by a small expansion. As the conductive particles move apart from each other, most of them no longer conduct current and the resistance of the device increases sharply. The material will stay Òhot,Ó remaining in this high resistance state as long as the power is applied. The device will remain latched, providing continuous protection, until the fault is cleared and the power is removed. Reversing the phase transformation allows the carbon chains to re-form as the polymer re-crystallizes. The resistance quickly returns to its original value.
ST 3
50
RA 090
RA
075
RA
060
RA
600
RA
400
RA
300
R E S E T TA B L E C I R C U I T P R O T E C T I O N When it comes to Polymeric Positive Temperature Coefficient (PPTC) circuit protection, you now have a choice. If you need a reliable source, look to polymeric resettable fuses from SCHURTER. Polymeric fuses are made from a conductive plastic formed into thin sheets, with electrodes attached to either side. The conductive plastic is manufactured from a nonconductive crystalline polymer and a highly conductive carbon black. The electrodes ensure even distribution of power through the device, and provide a surface for leads to be attached or for custom mounting. The phenomenon that allows conductive plastic materials to be used for resettable overcurrent protection devices is that they exhibit a very large non-linear Positive Temperature Coefficient (PTC) effect when heated. PTC is a characteristic that many materials exhibit whereby resistance increases with temperature. What makes the polymeric conductive plastic material unique is the magnitude of its resistance increase. At a specific transition temperature, the increase in resistance is so great that it is typically expressed on a log.