ICP-S Technical Manual

Overcurrent Protection Elements

Rev.A

5/13

5. Checks with I

If the steady-state current includes a pulse, surge, or inrush-current, use the I

graph and check that the ICP will not deteriorate regardless of the mode of the

current or the ICP will not break the steady-state current while the ICP is in operation.

• Even though the Joule integral value of the current wave form designed at your end is

within the safety area, it is recommended that you confirm the steady-state current for

the safety of the components

in the graph. If the value is in the safety area, it is okay to use the selected ICP model.

If the value is, however, beyond the safety area, use an ICP model with higher ratings.

• Note: The inspection and selection of the ICP according to the Joule integral value is

absolutely based on the results of the approximation of the current wave form.

Be sure to inspect all the current wave forms of your application, or otherwise the safety

of the application will not be fully ensured.

• Consider a safety margin with the dispersion of component characteristics taken into

calculation when inspecting and selecting the ICP, if it is impossible to check the worst

current wave form.

I

Breaking current area: The ICP breaks the current in this area.

Deterioration area: Although the ICP does not break the current instantaneously,

the ICP may break the current as a result of ICP deterioration.

Marginal area: The area where the risk of ICP deterioration is low.

Basically avoid using this area.

Safety area: The ICP will not deteriorate or break the current.

Precautions

t (s)

Breaking

current area

Safety area

Deterioration

area

Margin area