FSequence IPM Owners Guide.book Page 34 Thursday, October 6, 2011 3:33 PM
Freedom Sequence Operational Concepts
AC Load Shedding
When the current draw from the main AC source increases beyond the current clamp, Freedom Sequence power manager starts to shed (to disconnect) AC load circuits in a priority order set by the installer. Circuits having the lowest ranking priority gets shed first.
Freedom Sequence takes into account the Line Association of a circuit for load shedding when it operates with a split phase AC source. It will shed the circuit with lowest ranking priority with the group of circuits associated to the line that is overloaded.
When it operates from a single phase supply, Freedom Sequence does not check for line association before shedding the lowest ranking priority load circuit.
After an overload condition is detected, Freedom Sequence waits for two seconds to check if the overload persists before disconnecting a load circuit. If the overload condition is corrected it will not disconnect any load circuit, otherwise, it will shed the lower ranking priority circuit.
If disconnecting of one load circuit was not enough to correct the overload condition, the power manager will continue to shed the next lowest priority ranking load that is On until the overload condition is corrected.
The Freedom Sequence power manager keeps in its onboard memory the current each load circuit was drawing before it got disconnected. This current is displayed on the SCP as the Last Shed Current. The power manager uses the two values, Reconnect MRGN and Last Shed Current to determine if adequate headroom of current is available to reconnect the load circuit. If the headroom of current was available throughout the Connect Seq Delay period the power manager would reconnect the
circuit. However, if during this Connect Seq Delay period the available headroom falls below the Reconnect MRGN plus Last Shed Current then, the power manager will not reconnect the circuit.
The Freedom Sequence power manager will reconnect circuits in the order of highest ranking load circuit in the Off setting. When operating on a split- phase AC, the power manager will reconnect specifically those load circuits which are associated to the line that has adequate headroom.
While operation on a
See the illustration on the next page.
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