Lucent Technologies 555-670-116 Power Supply Unit Load Requirements, Unit Load Calculation Rules

MERLIN LEGEND Communications System Release 7.0				Issue 1
Pocket Reference 555-670-116				April 1999
Power Supply Unit Load Requirements				90
	Power Supply Unit Load Requirements
	Unit Load Calculation Rules
		Installed
	Mode	Modules	Calculation
	Hybrid/PBX,	61	Not required.
	Modified Key,
	or
	Behind Switch
	Square Key	4 or fewer2	Not required.
	or
	Behind Switch
	Square Key	5 or more	Use the “Unit Load Rating of System
	or		Modules” table and instructions below to
	Behind Switch		determine the estimated unit loads (ULs):
			■ If the ULs < 96 and the 391C1power

supply is used, or the ULs < 72 and the 391A3 power supply is used, then no calculation is required. If a 391A1 or 391A2 power supply is used and the ULs > 48, then replace the power supply with a 391C1 power supply.

■ If ULs > 96, reconfigure the system so that the total ULs does not exceed 96 per carrier.

For more information on unit load calculation, refer to Appendix F of System Planning.

1The 391A1 and 391A2 power supply units generally support 6 modules of any type in Hybrid/PBX mode. However, if all 6 carrier slots meet the following conditions, the unit load total may exceed 48:

Only MLX or analog multiline station modules are installed.

More than 45 MLX-20L or 34-button analog multiline telephones are installed.

The 391C1 and 391A3 power supplies have maximum ratings of 96 and 72 unit loads respectively. Use these power supplies in place of a 391A1 or 391A2 on systems where unit loads will exceed 48.

2The 391A1 power supply unit generally supports 4 modules of any type in Square Key mode.