"user manual"
Contents
1. The thermal cutoff operates when the thermal element within melts Therefore if the thermal element does not reach the operating temperature the cutoff will not activate even if the ambient temperature has risen to the operating temperature In addition a short lag time might result in the event of a sudden rise in the ambient temperature or if the thermal cutoff only detects part of the temperature increase Y Thermal cutoff should be mounted such that the temperature gradient is equal throughout the thermal cutoff If lead B of the SF type which is caulked to the metal case is mounted in such a way that it only conducts heat to the metal case the temperature around the thermal pellet would always be higher than other parts in the metal case This could lead to the thermal cutoff opening prematurely Hence it is recommended that lead A which is the resin sealed side be connected nearer to the heat source It should also be mentioned that similarly if lead A is fixed in a location whereby the temperature it is exposed to is always lower than that of lead B the thermal cutoff could also be prematurely triggered except SFH E series Designers of the end application should take into account the maximum surface temperature of the thermal cutoff as shown in Table 1 and avoid exceeding this level If the body temperature of the thermal cutoff is exceeded on a regular basis the thermal cutoff may start operating at temperatures low2. Cautions SEFUSE This section describes points to note about the design installation and storage of NEC SCHOTT SEFUSE thermal cutoffs so as to achieve the optimum performance of these thermal protection devices E Design Do not use this device for any purpose other than as a thermal cutoff The thermal cutoff is designed to detect abnormal rises in temperature and open the electrical circuits as required It is not a current fuse that cuts off excess current If thermal cutoff is used as a current fuse it may malfunction Do not use this device in aerospace equipment aeronautical equipment nuclear reactor control systems life support equipment or systems transportation machinery engine control or safety related equipment This device is designed for use in household electrical appliances office automation equipment audio and video equipment computer communications equipment test and measurement equipment personal electronic equipment and transportation equipment excluding engine control Decisions regarding the type of thermal cutoff the installation location and the mounting method should be made by customers based upon the requirements of the end application It is recommended that designers test the final design with the selected thermal cutoff under both normal conditions as well as predicted worst case scenario Y Thermal cutoff should be mounted where it can detect abnormal heat as quickly as possible
3. ck 3 X ray inspection 4 Operation check for sampling Be careful when mounting the thermal cutoff because external force heat or a harmful atmosphere containing excessive humidity or sulfurous acid gas may damage the characteristics of the thermal cutoff If applicable it is recommended that the general consumers who are unaware of the usage cautions for thermal cutoff be informed not to mount remove or replace the thermal cutoff through a note to this effect in the user s manual and other related material For any clarifications or more information about these cautions please kindly contact NEC SCHOTT Components Corporation The values contained in this document were obtained under the testing conditions conducted by NEC SCHOTT These are not guaranteed and are for reference only The information herein is based on the documents as of July 2011 and is subject to change without notice Therefore it is recommended to refer to latest individual information such as drawing for mass production designing lt is prohibited to reprint or copy the contents herein without written agreement of NEC SCHOTT Components Corporation If problems relevant to the industrial property right of third parties occur by using the products we would not assume any responsibility for matters other than ones directly related to the manufacturing process which please note Although we have been making continuous efforts to improve the quality and
4. er than the normal operating temperature Malfunctions may also occur In case sor using SM type and D6 type in DC rating please kindly contact NEC SCHOTT Components Corporation 23 Table 1 Fuse Body Fuse Body Sart Number Fuse Body basnie Fuse Body Temperature Pan Number Temperature man ymber Temperature z Temperature 52C SF70E K Y L 50 C SFi67_ 140 C f SFH106 yy 86 C 72C SF76E K Y L 56 C SF169E Y L 140 C SFH109E 89 C SM110A B G 90 C SFOOL 70 C SF184 E Y L 140 C SFH113E 98 C SM125A B 106 C SF91E K Y 71 C SF188E K Y L 140 C SFH117E 97 C SM137A B G 117 C SF96E K Y L 76 C SF214E K Y L 1400 E 104 C SM146A B G 126 C SF113E Y L 90 C SF226E Y 140 C SFH129E 109 C SM150A B 126 C ogc SF229L 140 C SFHIS4E 114 C a yl YL 109 C SF240E Y L 140 C SFHIS2E 132 C SEY nse oo SFH162E 140 C n SF152E Y L 1320 SFH172E 140 C Note that the temperature listed in Table 1 refers to the surface temperature of the thermal cutoff and not the ambient temperature Thermal cutoffs have a limited life The thermal elements used are durable substances designed for long time usage However the longevity of the thermal cutoff depends on the conditions in which it is exposed to This is particularly true if the thermal protection device is frequently exposed to temperature very close to its operating tempera
5. off to operate After mounting the thermal cutoff be careful not to apply force that may pull push or twist the lead wires If using a SF type_thermal cutoff the lead on the resin sealed side must not be allowed to touch the case This would cause the currento flow ftom the lead on the resin sealed side to the opposite lead so that the thermal cutoff cannot open the circuit Note that the body of the SF type is the same in potential as the circuit Therefore it must be electrically isolated from the other metallic part SSS 25 rs E Storage The body and lead A of the SF type and the leads of SM092A and SM092B are silver plated Therefore these parts may discolor because of sulfuration making the marking of the body difficult to discriminate or negatively affecting the solder ability of the lead To avoid this the thermal cutoff should not be kept around materials such as cardboard or rubber etc which generate sulfurous acid gas When storage of thermal cutoff in cardboard boxes is required the pack of thermal cutoffs should be double packed and sealed in bags such as polyethylene E Recommendation e NEC SCHOTT recommend the following tests upon receipt and after mounting of the thermal cutoff as it may have undergone some mechanical load or thermal influence during transportation or when being mounted 1 Appearance check 2 Resistance check comparing before with after or conductive che
6. reliability of our products the possibility _ of defects cannot be eliminated entirely Therefore when using our electronic component products please make sure to consider safety measures in its design such as redundancy fire containment and malfunction prevention against physical injuries fire disasters and social damages in consideration of the said defect occurrences Our products are classified into 2 quality grades Standard and Special The recommended applications of the products according to its quality level are indicated below If you intend to use our products for applications other than Standard level please make sure to consult with our sales representative in advance Standard it oes ea Computers office equipment communication equipment measuring equipment audio amp visual equipment home electric appliances machine tools personal electric equipment and industrial robots etc Special Transportation equipment automobiles trains ships and others aircrafts aerospace equipment medical equipment for life support etc 2 26
7. rmal cutoff should be SF type 98N or less SM type 49 N or less and D6 type 4 9N or less With regards to the SF type deformation of the case may change the location of the sliding contact during operation and could lead to the thermal cutoff operating only at temperatures lower than the normal operating temperature range The thermal cutoff may also not operate even if the thermal cutoff s operating temperature is exceeded Mounting Thermal cutoff can be mounted by soldering caulking or welding The connecting position at the lead of resin sealed side should be 5 mm or more from the body of the thermal cutoff SF Type SM Type connecting connecting 5 mm or more position position D6 Type 5 mm or more 5 mm or more 5 mm or more i 5 mm or more connecting position If soldering note that the thermal cutoff may function because of excessive solder temperature To prevent such malfunctions for example holding the lead near the case with a tool is effective for allowing the heat to escape and the soldering should be done in short intervals Another effective method is to use a lower solder temperature and to solder at a location that is at a distance from the case i If caulking or welding be careful to keep the resistance value of the connecting section low If the connecting section has a high resistance value the passing current may generate an abnormally high temperature that will cause the thermal cut
8. teriorate the sealing resin or lead to cracks in the case of the thermal cutoff due to corrosion The thermal cutoff could thus operate at lower than operating temperatures or not activate even if its operating temperature is exceeded except SF Y series SM type and D6 type The thermal cutoff corresponds to industrial waste The thermal cutoff corresponds to industrial waste and requires disposal according to governmental and provincial regulations The services of a licensed disposal contractor could also be engaged The thermal cutoff is a non repairable device In case of replacement an equivalent thermal cutoff from the same manufacturer should be used For general consumers who are not aware of the cautions associated with the thermal cutoff they should be informed not to mount remove or replace the thermal cutoff through a note to this effect in the user s manual and other related materials 24 Cautions SEFUSE Lead wire process When bending the lead wire it is important not to apply excessive pressure to the root of the lead wire Therefore the lead wire should be secured close to the case and bent not twisted at a distance 3 mm or more from the body of the fuse SF SM Type D6 Type 3 mm or more 3 mm or more Secured Secured gt Secured Secured The tensile strength applied to the lead wire should be SF type 49N or less and SM and D6 types 9 8N or less The strength applied to the body of the the
9. ture Hence it is recommended that designers conduct a reliability test by fixing the thermal protection device onto the actual end application and simulating the expected operating conditions to assess the lifetime of the device The body temperature of the thermal cutoff increases as current passes through it The body temperature of the thermal cutoff could rise to levels higher than the ambient temperature as the current passes through the device In addition the body temperature could also increase depending on a number of factors such as the mounting method Hence it is recommended that designers measure the body temperature of thermal cutoff after conducting a reliability test Use the thermal cutoff with a voltage and current level lower than the rated level If the thermal cutoff is used with a voltage or current level higher than the rated level the contacts may be welded together in the SF type causing the thermal cutoff to malfunction In the SM type and D6 type the body of the thermal cutoff may rupture j Do not use the thermal cutoff in an atmospher out of the standard specifications such as in environments exposed to sulfurous acid gas nitrogen oxide gas ammonia gas or conditions that contain formic acid It is also not suitable for high humidity situations and submersion in a liquid The case of the thermal cutoff is made with a copper alloy brass Hence installing the thermal cutoff in such conditions or similar could de
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