Cautions for Handling Operations of Thermal-Links
Use the thermal-links, giving thorough attention to the following:[1] Cautions for Design of lnstallation of thermal-links
- Prepare design such way that the lead wires on both sides of thermal-links and its body can fully receive heat.(Fig.1)
- Extend the lead wire of thermal-links as long as possible to enable easy detection of heat.
- When using thermal-links for coiled devices (such as motors and transformers), install the cutoff at a point most easily detect the heat.
- When using the LE/LE-T type, design the system to install the fuse in such a manner that no temperature gradient occurs in the thermal-links body. If the heat from a heat source is transmitted only from an end of the metallic case where the lead wire is staked for an extended period of time, the service life of the thermal-links may be reduced or an abnormal blowing of the thermal-links may result. When it is inevitable to accept the heat from the lead wire on an end, connect the lead wire on the epoxy resin side to the heat source side.
- In the LE/LE-T type, an electric current occurs in the
metallic case of the thermal-links. As the case is not
insulated, be careful about that. Also note that when the
lead wire in the epoxy resin side is contacting on the
metallic case, the circuit cannot be broken even when the
movable contact function.
Be careful not to allow the lead wire in the epoxy resin side
to contact on the metallic case.
[2] Cautions for thermal-links lnstalling Operations
- When using by bending lead wires, hold the base of lead wires firmly and gently bend the point detached more than 3mm from the body of thermal-links. (Fig.2)
- Exercise care not to damage the case and lead wires when bending the lead wires.
- Exercise care not to give forcible tensions, thrust or twist to the lead wires.
- Conduct tests under actual working conditions and see that lead wires will be free from tensions or thrust shown in Table 3. Assure also that no excessive twist will be given.
- Never turn the lead wire as against the body (case).
- In the LE/LE-T type, when the case is deformed, the travel of movable contact may be restricted, causing abnormal functioning in some cases. Pay attention not to allow a load on the case that causes case deformation.
Table 3. Specifications for tensions, thrust and twist based on JIS C6691
| Types | Tensions | Thrust | Twist |
| N, T, K | 4.5N (0.45kgf) | 1.2N (0.12kgf) | 90°／1time |
| H, HU | 4.8N (0.49kgf) | 1.2N (0.13kgf) | 90°／1time |
| V | 5.3N (0.54kgf) | 1.4N (0.14kgf) | 90°／1time |
| E, Y | 7.7N (0.79kgf) | 2.0N (0.20kgf) | 90°／1time |
| L, LE, LE-T | 15.8N (1.61kgf) | 4.0N (0.41kgf) | 90°／1time |
[3] Conditions for Soldering Lead Wires
1K-F, T-F, V-F, Y-F, L-F, N-F, H-F, E-F, HU-F types- See that no excessive heat resulting from soldering will be transmitted to thermal-links. Perform soldering at the lowest possible temperature and in a shortest possible time. When soldering at a high temperature and for a long time, It is recommended to radiate heat by pinching lead wires with a jig like a pair of pliers.
- Table 4 shows, for your reference, the soldering distance and time using a soldering tank at temperature 420°C±5°C
(Control heating to the necessary minimum level). - Careful not to give forcible tensions or thrust during and immediately after soldering. It may lead, other wise, to the possibility of softening the sealant, which fastens lead wires, making them defective.
- Leave standing for more than 30 seconds after completion of soldering. During the heat-radiating period, do not move the body of thermal-links and lead wires. If extreme stress was imposed before the thermal-links are cooled down, that may cause defective products. When performing resoldering, do so after cooling down thermal-links to room temperature.
- Reflow soldering is impossible.
Table 4. Soldering characteristic(420±5°C)
●Axial type
| Type | Tf[°C] | Soldering distance | ||
| 10mm | 20mm | 30mm | ||
| K-F | 65 | ＊ | ＊ | ＊ |
| 76 ～ 102 | ＊ | ＊ | 1 | |
| 115 ～ 127 | ＊ | 3 | 5 | |
| 133 ～ 145 | 1 | 3 | 5 | |
| T-F | 65 | ＊ | ＊ | ＊ |
| 76 ～ 102 | ＊ | ＊ | 1 | |
| 115 ～ 127 | ＊ | 3 | 5 | |
| 133 ～ 145 | 1 | 5 | 5 | |
| V-F | 65 | ＊ | ＊ | ＊ |
| 76 ～ 102 | ＊ | ＊ | 3 | |
| 115 ～ 127 | ＊ | 3 | 5 | |
| 133 ～ 145 | 1 | 5 | 5 | |
| Y-F | 65 | ＊ | ＊ | 1 |
| 76 ～ 102 | ＊ | 1 | 3 | |
| 115 ～ 127 | ＊ | 5 | 5 | |
| 133 ～ 145 | 1 | 5 | 5 | |
| L-F | 76 ～ 102 | ＊ | 1 | 3 |
| 115 ～ 127 | ＊ | 5 | 5 | |
| 133 ～ 145 | 1 | 5 | 5 | |
| Unit : sec. |
●Radial type
| Type | Tf[°C] | Soldering distance | ||
| 10mm | 20mm | 30mm | ||
| N-F | 65 | ＊ | ＊ | ＊ |
| 76 ～ 102 | ＊ | ＊ | ＊ | |
| 115 ～ 127 | ＊ | ＊ | 5 | |
| 133 ～ 145 | ＊ | 3 | 5 | |
| H-F HU-F |
65 | ＊ | ＊ | ＊ |
| 76 ～ 102 | ＊ | ＊ | 1 | |
| 115 ～ 127 | ＊ | 3 | 5 | |
| 133 ～ 145 | 1 | 5 | 5 | |
| E-F | 65 | ＊ | ＊ | ＊ |
| 76 ～ 102 | ＊ | ＊ | ＊ | |
| 115 ～ 127 | ＊ | 1 | 5 | |
| 133 ～ 145 | 1 | 5 | 5 | |
| Unit : sec. |
＊ : Prevention of thermal conduction is necessary.
- See that no excessive heat resulting from soldering will be transmitted to thermal-links.
- Table 5 shows, for your reference, the soldering distance
and time using a soldering tank at temperature 420°C±5°C
(Control heating to the necessary minimum level). - When per forming automatic dip soldering, properly regulate preheat temperature.
- Careful not to give any forcible tension, thrust or twist to the lead wires during soldering operations and in installing operations. Or else, such force may lead to the possibility to result in defective products, by softening the sealant, which fasten the lead wires.
- Leave standing for more than five minutes after completion of soldering operations. During the heat-radiating period, do not move the body of thermal-links and lead wires.
- Reflow soldering is impossible.
Table 5. Soldering characteristic(420±5°C)
●Axial type
| Type | Tf[°C] | Soldering distance | ||
| 10mm | 20mm | 30mm | ||
| T-X | 65 | 1 | 5 | 5 |
| 76 ～ 102 | 1 | 5 | 5 | |
| 115 ～ 127 | 5 | 7 | 7 | |
| 133 ～ 145 | 5 | 7 | 7 | |
| Unit : sec. |
●Radial type
| Type | Tf[°C] | Soldering distance | ||
| 10mm | 20mm | 30mm | ||
| N-X | 65 | ＊ | ＊ | 1 |
| 76 ～ 102 | ＊ | 1 | 5 | |
| 115 ～ 127 | ＊ | 3 | 5 | |
| 133 ～ 145 | 1 | 3 | 5 | |
| H-X HU-X |
65 | ＊ | ＊ | 1 |
| 76 ～ 102 | ＊ | 3 | 5 | |
| 115 ～ 127 | 3 | 5 | 7 | |
| 133 ～ 145 | 5 | 5 | 7 | |
| E-X | 65 | ＊ | ＊ | 1 |
| 76 ～ 102 | ＊ | 3 | 5 | |
| 115 ～ 127 | 1 | 5 | 7 | |
| 133 ～ 145 | 3 | 5 | 7 | |
| Unit : sec. |
＊ : Prevention of thermal conduction is necessary.
[4] Cautions for crimping and Welding Operations
- When installing thermal-links by crimping or welding, securely connect by separating for more than 3mm from thermal-links so that no stress will be given to the sealant.
- Establish the conditions for crimping or welding after verifying the contact resistance and connecting strength of the joints. If the conditions of connection were inadequate, contact resistance will grow large to generate excessive heat, which will lead to the possibility of premature breaking of thermal-links.
[5] Cautions for Quality Control
-
To check the conditions of thermal-links on delivery and after
their installation, the measurement of resistance between lead
wires and checking of internal conditions by X-ray will prove
to be effective means.
[6] Cautions for Storage
- Store thermal-links packed in boxes and polyethylene bags at places where temperature is in the range from -10 to 40°C, relative humidity from 30 to 75% and are free from direct sunbeam, vibration and impact.
- In the LE/LE-T type, silver plating is applied to some areas which may be discolored from sulfating, etc., reducing solderability. When storing, do not allow the thermal-links to contact on an object that emits sulfuric gas such as cardboard, rubber band, etc. It is recommended to use promptly after unsealing a thermal-links. If the thermal-links should be stored for a long time after unsealing, keep it in a sealed container to prevent a contact with sulfuric gas.
Cautions for Handling Thermal-Links
Safety cautions
The information here gives cautions to be exercised in handling thermal-links for retaining their function.
Please be carefully and surely understanding the cautions mean before using.
Prospective purchasers of the products listed in this catalogue are requested to make a purchase contract
and obtain delivery specification sheet from Tamura Thermal Device or its agent.
The design and specifications of the products in this catalogue are subjected to modifications without a prior
notice.
Customers will have to assume the responsibilities for any accident, which may occur from inappropriateness to deal with them, and our company will not be held responsible for them.
[1] Do not use as current fuse.
Thermal-Links are made for the purpose of cutting off circuits by detecting abnormal rise in heat.
They have no function as current fuse to cut off on exposure to over-current.
If used as current fuse, they not only work as current fuse, but also as thermal-links so that they could end up as the
cause of accidents.
[2] Since temperature rating and electricity rating are specified for thermal-links, using at less than each ratings range.
If electricity greater than the rated voltage or rated current were passed, self generation of heat will become greater to
cause premature fusing and strong arc current at the time of working, which causes abnormality in outer appearance
(crack and deformation of body) and the deterioration in insulation.
Use the cutoff, therefore, within the rated voltage and current.
In this case, when excessively large overcurrent is imposed, decide the advisability of use after repeated performance of
check tests on assumption of worst conditions by models.
[3] Design the equipment that thermal-links won't exceed the normal operating temperature as shown in Table1 and Table2.
If used over the normal operating temperature, it may cased earlier, delayed and abnormal fusing generated.
If used at a temperature which close to the functioning one, the thermal-links may work at times while they are in using.
[4] Once the thermal-links were actuated, design the equipment in such a way not to exceed the maximum temperature limit.
[5] Do not use for aviation and space equipment, aircraft equipment, nuclear devices, engine control devices of life support system and transport equipment and other devices related to them.
Thermal-Links are manufactured for the purpose of applying them to general equipment such as household electric products, OA equipment, computer communication equipment and measuring equipment.
[6] Do not use thermal-links in liquid such as water and organic solvent or in corrosive gases such as sulfur dioxide gas and nitrogen oxide gas or in the ambience of high humidity.
If used, it may lead to the possibility of thermal-links not working due to the deterioration of their materials.
[7] When left in an environment where there are extensive changes of ambient temperature for a long time, the fusible alloy may be deformed, causing the fuse to blow earlier or later than usual in some cases.
Check the working environment in advance for proper choice of thermal-links.
[8] Customers are required to select the types of thermal-links and decide the installation points and the method of installation according to their intended use and judge their suitability by themselves.
In order to judge the suitability of such decision, it is recommended to confirm, by repeated tests, normally using conditions of equipment and abnormal conditions predictable as far as possible.
[9] Care should be taken not to allow strong vibrations or excessive mechanical stresses applied to the thermal-links when in user's product.
Or the thermal-links may be blown earlier or later than usual.
[10] Provide a caution in the instruction manual or the similar of the fuse user's product notifying that a general consumer shall not replace the thermal-links.
Cautions for Storage
Products be packed in boxes or polybag shall keep in the place at normal temperature of -10°C∼40°C,relative humidly temperature of 30∼75%,and without rapidly temperature change,direct sunshine ,vibration and the impact.etc.