SM Cautions - nec schott
Contents
1. 75 C C SMI10ABG 90 C swt1oa 9 85 oes 0 Bo os C 5M1 254 5 Tan Sii 264 5 G sui 26a E E 95 0 bo C SMII0ABG 110 oaoa hio fio fioo Leo e SMIZ4ABG 114 C C C C C SMIS7ABG 117 C swisag 4 m E m E SM 45A BG ra 125 125 120 h20 15 smasaf eg p25 120 120 5 SM1 50A B os oh 644 140 C SMIBZA 1 The temperatures do not refer to ambient temperature but surface temperature of the thermal cutoff 2 When a large current flows through a thermal cutoff a temperature difference occurs between the case and the lead Therefore It is recommended to measure several points along the thermal cutoff and make designs such that the highest temperature does not exceed the temperature shown in Tables 1 and 2 3 Please contact us for DC ratings of other SM types 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 NEC SCHOTT e The body temperature of the thermal cutoff becomes higher as a current passes through and might become even higher than2. 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 to warn general consumers who are not aware of the usage cautions for the thermal cutoff not to mount remove or replace the thermal cutoff through a note to this effect in the user s manual and other related material
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. 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 so 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 e Designs should ensure that the temperature of the thermal cutoff does not exceed the temperatures shown in Table 1 and Table 2 If these temperatures are exceeded on a regular basis the thermal cutoff may 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 Table Recommended maximum body temperature Type Name Body on a require basis Temperature Body T i SMOF2A 5 C Tipe ei MA atlas SMOS2A B Ra C Hame a to gt to 3 A to 4 A to j A SMO92AB 72 C 3 swoesc 70 0 65 c 3 SMOS5AB G
5. ld be 1kgf 9 8N or less e The strength applied to the body of the thermal cutoff should be Skgf 49N or less 5 kgf ai 0 8 steel wire Mounting e SEFUSE can be mounted by soldering caulking or welding o Itis 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 a a _ 5mm or more 5 mm or more _ Connecting position 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 After mounting the thermal cutoff be careful not to apply force that may pull push or twist the lead wires 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
6. the ambient operating temperature see test data 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 mentioned method e The tensile strength applied to the lead wire shou
7. 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 Storage e The lead of SM092A B SM164A and SM182A are silver plated Therefore these parts may discolor because of sulfuration leading to 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 Ininstances 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 NEC SCHOTT Keep away from heat and moisture to avoid false operation of the thermal cutoff and sulfuration of silver plated parts Ref Temperature Max 40 C Humidity Max 80 Disposal Consideration 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 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 1 Appearance check 2 Resistance check comparing before and after or conductive check 3 X ray
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