Lucent Technologies Lineage
®
2000 400A, 60Hz Ferroresonant Rectifier J85503C-3
Issue 10 July 2000
Engineering and Ordering 3 - 3
the loss of any one rectifier does not cause the remaining rectifier
capacity to fall below the abh value. This is another way of saying that
the loss of any one rectifier in the system does not cause the batteries to
discharge. In some cases, meeting the mirc current requirement also
meets the additional requirement for a redundant system; in other cases
it does not.
Sizing Example
The following examples illustrate the sizing principles given above.
1. The average busy hour current (abh) of a plant is 2850A. The plant
is required to have a 4-hour reserve (discharge) time and a 24-hour
recharge time. Calculate the minimum installed rectifier capacity
(mirc) and the number of 400A rectifiers required in redundant
and non-redundant systems.
From Figure 3-1, a 24-hour recharge time intersects the 4-hour
reserve curve at a recharge factor of approximately 1.2.
mirc = abh x recharge factor
mirc = 2850A x 1.2 = 3420A
The number of 400A rectifiers required to supply at least 3420A is
nine (9 x 400A = 3600A). Nine rectifiers are required in a
non-redundant system. If one of the rectifiers fails, the remaining
rectifier capacity is 3200A (8 x 400A), which is greater than the
2850A abh. Therefore, nine 400A rectifiers are also sufficient for a
redundant system.
2. The average busy hour current drain (abh) of a plant is 210A. The
plant is required to have an 8-hour reserve time and a 24-hour
recharge time. Calculate the mirc and the number of 100A
rectifiers required in redundant and non-redundant systems.
From Figure 3-1, a 24-hour recharge time intersects the 8-hour
reserve curve at a recharge factor of approximately 1.38.
mirc = abh x recharge factor
mirc = 210A x 1.38 = 290A
The number of 100A rectifiers required to supply at least 290A is
three (3 x 100 = 300A). Three rectifiers are required in a
non-redundant system. If one of the rectifiers fails, the remaining
rectifier capacity is 200A (2 x 100A), which is less than the 210A
