Datasheet
1. BENDING LEADS
Care should be taken when forming the Thermal Cut Offs (TCO) leads. The TCO 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 TCO leads have not been cut, nicked, folded sharply, fractured or burned.
2. MECHANICAL FORCES DURING APPLIANCE CONNECTION
a. When installing the TCO, avoid unnecessary bending, twisting, pulling or pushing on the TCO 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 TCO body must maintain its cylindrical shape to function properly.
Excessive clamping could cause denting or crushing of the TCO body, which may lead to failure. X-ray and visual inspection of the TCO will
determine if the fuse body has been damaged.
c. Note that the TCO body is electrically live and must be insulated before applying a metal clamp over the TCO body.
d. Care should be used when pushing the epoxy end lead, to avoid the lead being forced into the TCO body.
This could result in failure.
3. SPLICES AND TERMINATIONS
By attaching free wire to the TCO leads, connections can be made by bending the free wire ; and keeping the TCO leads from being subjected to
undue stresses. Splices should be sized according to the size of the wire plus the TCO lead 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 TCO has been subjected to several high temperature cycles. Lead
connections used at 150
℃
(302°F) or higher should be soldered or welded.
4. SOLDERING LEADS
The TCO 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 TCO as well as burn the epoxy.
Assure that the leads are supported during soldering to avoid breaking or cracking of the epoxy.
5. WELDING LEADS
Excessive heat from resistance welding should not be conducted to the body of the TCO.
To avoid welding, internal parts, care should be taken that none of the welding current is conducted through the TCO. 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 TCO through the connecting lead on some applications.
By attaching the epoxy lead to the heat source, you thereby minimize the temperature increase of the TCO body from this heat fl ow. When locating
the TCO 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 TCO.
7. EXAMINATION FOR DAMAGE
An examination for damage of the TCO 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.
REPLACEMENT
It should be made clear for reasons of safety, that a TCO is a non-repairable item and that in case of replacement an equivalent TCO with the same
catalogue number shall be used and mounted in exactly the same way.
The performance of the Elmwood thermal cut offs requires proper handling during installation for it to operate in its intended manner. These
instructions are intended to be used to reduce the risk of malfunction of the thermal cut offs which may result from improper installation
during forming of leads, splicing, welding and soldering.
InstallationInstallation
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Secondary Operations: Cut Leads To Custom LengthsSecondary Operations: Cut Leads To Custom Lengths