Overload Curves

The curves can take one of three formats: standard, custom, or voltage dependent.

For all curve styles, the 469 retains thermal memory in a thermal capacity

used register which is updated every 0.1 second. The overload pickup determines

where the running overload curve begins.

The 469 standard overload curves are of standard shape with a multiplier value of

1 to 15.

The voltage dependent overload curves are used in high inertia load applications,

where motor acceleration time can actually exceed the safe stall time and motor

thermal limits. During motor acceleration, the programmed thermal overload curve

is dynamically adjusted with reference to the system voltage level. The selection

of the overload curve type and the shape is based on motor thermal limit curves

provided by motor vendor.