SF Cautions
Contents
1. lead forming be sure not to make the lead on the resin sealed side touch the case This would cause the current to flow from the lead on the resin sealed side to the opposite lead so that the thermal cutoff cannot break the circuit e 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 e When marking a thermal cutoff there is a concern that the marking will be removed when alcohol or other organic solvents are used There could also be an incidence whereby the marking transfers onto the insulation tube and becomes faint when the thermal cutoff is covered with it Please confirm the above before you use any organic solvents or insulation tubes on a thermal cutoff e In other mounting be careful of that the thermal cutoff may not function Confirm above before you mount for the thermal cutoff NEC SCHOTT Storage e The body and lead A are silver plated Therefore these parts may discolor because of sulfuration leading to a difficulty in discriminating the marking of the body or a decline in the solder ability of lead To avoid this SEFUSE should not kept in the environment of materials such as cardboard or rubber etc which generate sulfurous acid gas e In instances when SEFUSE needs to be stored in a cardboard box the SEFUSE packs should be placed into other bags such as polyethylene and well sealed e Keep away from heat and mo2. start operating only at temperatures lower than the normal operating temperature Malfunctions may also occur Even if the thermal cutoff s operating temperature is exceeded it may malfunction NEC SCHOTT Table 1 SF type SFH type Type Name Body Temperature Type Name Body Temperature OPROER T KOG oPHooE ajai SPF foEKY KAG oPHEZE 720 SFAT EK T Fae oPHETE iG SEK Y TAG SPH OSE 82 C oF11 GE aog S FHI 06E D C SF19EKY ggg o FH1 09E aoc oF1ZHE 109 S FHI 13E ga oF1 SHE 119 C SFAT FE a7 Si oie r Ilot o FHI 24E 1o4 C ELDA Sle lel es a FAI 29E 108 C ues o FHI 34E 114 C o FH1 52E 132 C 140 C ea SFHIAZE 140 C E a P2206 Y 1 The temperatures do not refer to ambient temperature but surface SF240E Y temperature of the thermal cutoff e The SEFUSE has a limited life Although the thermal elements are made of durable substances intended for long term usage their lifetime varies depending on using conditions The more frequently SEFUSE is used at the temperature close to the operating temperature the shorter the lifetime could be Therefore we recommend performing a reliability test with the SEFUSE mounted onto the actual application or under almost the same condition as the actual situation to assess the lifetime of the device e The body temperature of the thermal cutoff becomes higher as a Current
3. NEC SCHOTT Thermal Fuse od aken J Please review this section of cautions that has been designed to ensure the optimal performance of our thermal cutoffs To obtain the optimal performance from the thermal cutoff it is necessary for the customer to appropriately store the thermal cutoff design appropriate circuits for the application and perform evaluations mounting and testing as necessary Problems arising from the inappropriate execution of the above are at the risk of the customer NEC SCHOTT Components declines any and all responsibility Design Cautions e Do not use this device for purposes other than as a thermal cutoff The thermal cutoff is designed to detect abnormal rises in temperature and break circuits if needed It is not a current fuse that cuts excess current If used as a current fuse the SEFUSE may malfunction e 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 electric appliance office automation equipment audio and video equipment computer communications equipment test and measurement equipment personal electronic equipment and transportation equipment excluding engine control e The customer should select the proper thermal cutoff device mounting location and mounting method as appropriate for eac
4. d method e The tensile strength applied to the lead wire should be 5kgf 49N or less e The strength applied to the body of the thermal cutoff should be 10kgf 98N or less SF 10 key r B steel wire Mounting e SEFUSE can be mounted by soldering caulking or welding o It is recommended that the connecting position at the lead of resign sealed side should be 5 mm or more from the body of the thermal cutoff al _ 5mmormore Position of installation e f soldering note that the thermal cutoff may not function because of the excessive solder temperature To prevent such malfunctions for example holding the lead near the case by tool is effective for allowing the heat to escape and soldering should NEC SCHOTT be done in short intervals Another method is to use a lower solder temperature and to solder at a location that is at a distance from the case e lf 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 cutoff to operate break the circuit e tis recommended that the connecting position at the lead of resign sealed side should be 5 mm or more from the body of the thermal cutoff e After mounting the thermal cutoff be careful not to apply force that may pull push or twist the lead wires e When using an SF type with
5. h NEC SCHOTT application Verify whether the chosen selections are appropriate by repeatedly testing the final design for thermal cutoff under normal conditions as well as under predicted maximum abnormal conditions e Mount the SEFUSE such that it can detect abnormal heat as quick as possible The thermal cutoff operates when the inside thermal element melts Therefore if the thermal element inside does not reach the operating temperature the thermal cutoff does not operate even if the ambient temperature rises to the operating temperature When the ambient temperature rises suddenly or detect heat partially it may take time till the SEFUSE operates e Mount the SEFUSE so that the temperature is evenly distributed along every part of the device If the SF type lead B which is caulked to the metal case is mounted so that it only conducts heat to the body the temperature around the thermal pellet can be always higher than the other places in the metal case which can cause the SEFUSE to early open Be sure to connect the lead A the resin sealed side to the heat source Mounting the SEFUSE so that the temperature of the lead A is always lower than that of the lead B can also cause the SEFUSE to early open Except SFH type e Designs should ensure that the temperature of the thermal cutoff does not exceed the temperatures shown in Table 1 If these temperatures are exceeded on a regular basis the thermal cutoff may
6. isture to avoid false operation of the thermal cutoff and sulfuration of silver plated parts Ref Temperature Max 40 C Humidity Max 80 Disposal Consideration e The thermal cutoff corresponds to industrial waste so dispose it according to governmental and provincial regulations or engage the services of a licensed disposal contractor Recommendations e We recommend the following tests upon receipt of SEFUSE and after mounting it as it may have a mechanical load or thermal influence under transportation or when being mounted i 2 3 4 Appearance check Resistance check comparing before and after or conductive check X ray inspection Operation check for sampling N N SN e 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 to warn general consumers who are not aware of the usage cautions for the thermal cutoff not to mount remove or replace the NEC SCHOTT thermal cutoff through a note to this effect in the user s manual and other related material
7. passes through and might become even higher than the ambient operating temperature see test data NEC SCHOTT The temperature may rise even higher depending on the mounting method and other conditions Therefore after mounting the thermal cutoff under the same conditions you would use for the actual application run the final product and measure the body temperature of the thermal cutoff e 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 body of the thermal cutoff may be destroyed e Do not use the thermal cutoff in water organic solvents or other liquids or environments containing sulfurous acid gas nitrous acid gas or high humidity Doing so will cause deterioration of the sealing resin the thermal cutoff may operate at lower than operating temperatures or malfunctions to occur Also the thermal cutoff may not operate even if its operating temperature is exceeded Lead Wire Process e When bending the lead wire in order not to apply excessive pressure to the root of the lead wire secure the lead wire close to the case and bend the part beyond the secured section The lead wire should be bent at a distance of 3 mm or more from the body of the fuse and should not be twisted NEC SCHOTT 3 mmr more St Lareed Secured e When cutting the lead wire cut according to the above mentione
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