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Procedure 9-5 (continued)
Adjusting the load sharing
Action
Step
1
2
3
4
5
6
7
8
9
AccessNode Modular Business Package VTBM Ring User Guide P0904244 Issue 1.0
Action
Ensure that all rectifiers are ON and all BEM circuit breakers are ON.
Examine all rectifiers for the status of the RFA LEDs.
To coarsely adjust the load sharing of multiple rectifiers, determine the
condition that applies to your installation and go to the step indicated:
If
only one RFA LED is
illuminated green
the RFA LED on both rectifiers
is illuminated green
On the rectifier that has the RFA LED illuminated green, slowly and very
slightly adjust the FLT potentiometer counterclockwise until the RFA LED of
the other rectifier illuminates green.
Examine and compare the display of the ammeters on the rectifiers.
Note: Nortel Networks recommends that the ammeters of all installed
rectifiers read within 0.1 A of each other for proper load sharing.
Adjust the FLOAT voltage of the rectifier that has the lowest current reading
on the rectifier ammeter display by slowly and very slightly adjusting the FLT
potentiometer clockwise until the ammeter reading is no longer the lowest.
Note: The FLT potentiometer load sharing adjustment is very sensitive. Small
adjustments can reflect large changes in the ammeter readings.
Adjust the FLOAT voltage of the rectifier that has the highest current reading
on the rectifier ammeter display by slowly and very slightly adjusting the FLT
potentiometer counterclockwise until the ammeter reading is no longer the
highest of the installed rectifiers.
Note: The FLT potentiometer load sharing adjustment is very sensitive. Small
adjustments can reflect large changes in the ammeter readings.
Repeat from step 4 until the RFA LED on both rectifiers is illuminated green
and the ammeter displays read within 0.1 A of each other.
On the LVD unit, turn the SENSE DIP switch positions 1 and 2 to the right.
When all rectifiers are adjusted, you have completed the rectifier adjustment
procedures and the rectifiers are ready for service. Go to Procedure 9-6,
"Return the system to service."
—end—
Replacing the low-voltage disconnect unit 9-17
Then
The rectifier with the green RFA LED is
floating slightly too high.
Go to step 3.
The rectifiers are sharing the load closely.
Go to step 4.
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