Nortel Networks DCT1900 Power Consumption from Power Supply Related to Cable Length, Example

Technical Product Manual - DCT1900

Configuration Directions, Base Station Powering

4.5Alternative for Calculating the Power Consumption per Base Station

In Figure 4–4 the power consumption of the Base Station and the cabling is given as a function of the cable length in terms of percentage. This relation is almost independent of the number of cable pairs, cable resistance and supply voltage. Table 4–5 also gives this relation in steps of 5 percent. The table can be used as follows.

Power required from power supply (Watts)

15

7 5

0 100%

Maximum cable length

Fig. 4–4 Power Consumption from Power Supply Related to Cable Length

Example
z	supply voltage	:	48V
z number of EPP (Express Powering Pairs)		:	0
z	wire size	:	24 AWG (Rtp =0.055 /m)
z	length	:	820 ft.

With this information the maximum cable length can be read from Table 4–2. The maximum length can also be calculated using the formulas in Paragraph 4.4. When using these formulas, you must use n=2 for the number of pairs (2 data pairs, no express powering pairs). With both methods the result is 2763ft.

The length of the cable is (820/2763) 100%+29.7% of the maximum cable length. Round up this value (30%) and read the dissipated power from Table 4–5. The dissipated power is 8.3W.

4-8	Config-DCT1900/R8/mw
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