These instructions are intended to be used to reduce the risk of malfunction of the thermal cutoff to ensure that it performs in it's intended manner.
1. Bending Leads
Care should be taken when forming the thermal cutoff Ieads. The thermal cutoff leads must be supported 1/8" from bend and case; and 1/8" from bend and epoxy. This will prevent the epoxy seal from cracking which may result in premature degradation of the pellet. A close visual inspection should be performed to make sure that the thermal cutoff leads have not been cut, nicked, folded sharply, fractured or burned.
2. Mechanical forces during appliance connection
a. When installing the thermal cutoff, avoid unnecessary bending, twisting, pulling or pushing on the thermal cutoff leads. Care should be taken to avoid cracking or chipping of the epoxy which may result from sharp twisting or bending of the lead.
b. The thermal cutoff body must maintain its cylindrical shape to function properly. Excessive clamping could cause denting or crushing of the thermal cutoff body, which may lead to failure. X-ray and visual inspection of the thermal cutoff will determine if the fuse body has been damaged.
c. Note that the thermal cutoff body is electrically live and must be insulated before applying a metal clamp over the thermal cutoff body.
d. Care should be used when pushing the epoxy end lead to avoid the lead being forced into the thermal cutoff body. This could be result in failure.
3. Splices and terminations
By attaching free wire to the thermal cutoff leads, connections can be made by bending the free wire and keeping the thermal cutoff leads from being subjected to undue stresses. Splices should be sized according to the size of the wire plus the thermal cutoff Iead wire. The connections must be electrically sound to prevent high resistance and secure enough to withstand the rated cutoff temperature. Improper connections may cause damage to the seal or other parts and may result in nuisance tripping of the devices due to the generation of excessive heat at a faulty high resistance junction. High resistance junctions may form after normal operation of end use equipment and if the thermal cutoff has been subjected to several high temperature cycles. Lead connections used at 150°C (302°F) or higher should be soldered or welded.
4. Soldering Lead
The thermal cutoff leads require heat sinking during soldering operations. Lower temperature rated fuses may require more heat sinking than do higher rated fuses. Samples should be X-rayed before and after soldering to insure a consistent pellet height. Reduction of dimension of the thermal pellet indicates that more heat sinking is required. Also, excessive heat conducted by the leads could shorten the life of the thermal cutoff as well as burn the epoxy. Assure that the leads are supported during soldering to avoid breaking or cracking of the epoxy.
5. Welding Lead
Excessive heat from resistance welding should not be conducted to the body of the thermal cutoff. To avoid welding internal parts, care should be taken that none of the welding current is conducted through the thermal cutoff. A welding current of hundreds of amperes could weld the internal parts together resulting in a failure. The leads must also be supported during welding to avoid breaking or cracking of the epoxy.
6. Protection against overheating
A certain amount of heat is transmitted to the body of the thermal cutoff through the connecting lead on some applications. By attaching the epoxy lead to the heat source, you thereby minimize the temperature increase of the thermal cutoff body from this heat flow. When locating the thermal cutoff near a heat source, the device should be protected from overheating during operation. Normal operation overheating may cause premature opening of the device and excess overshoot may cause damage to the thermal cutoff.
7. Examination for damage
An examination for damage of the thermal cutoff should be done after the device-to-appliance connections are made. X-raying before and after the assembly operation and close visual inspection with special attention made at the epoxy, should be performed on early production samples.
D-TEMP thermal cutoffs are a non-repairable item and that, in case of replacement, an equivalent thermal-link from the same manufacturer and having the same catalog number should be used, mounted in exactly the same way.
D&M always suggests and encourages customers to test samples of these devices to determine suitability within each application. Designers should understand that overtemperature protection can be affected by installation and/or improper thermal cutoff location.
Seller's and manufacturer's only obligation shall be to replace such quantity of the product proved to be defective. Neither seller nor manufacturer shall be liable for any injury, loss or damage, direct or consequential, arising out of the use of or the inability to use the product.