Users Manual Part 1
• AC operation (within 90 VAC to 264 VAC; 45 Hz to 66 Hz) and switch over to DC backup operation
when AC failed
The PSU handles the automatic switch over to a backup battery in the event of AC mains failure.
CAUTION: An external disconnect device and appropriate 20A fuse are required on the DC
power supply line.
CAUTION: If the DC input on the station is connected to back up batteries, an external Low
Voltage Disconnect (LVD) device should be introduced directly in the power line in order to
protect the batteries against deep discharge. On the MTS 2, one relay rated min. 20 A/55 VDC
should be introduced. And for the MTS 4, two of these units should be used, one for each of the
two incoming DC lines. Alternatively for the MTS 4, one relay rated 40 A/55 VDC can be used if
the two DC lines are connected to one battery pack. The relays should be controlled in a way
that they disconnect the batteries once the voltage drops below 40.5 V, where the PSU in the
MTS shuts down. Two Motorola Solutions kits are available for this purpose:
• MTS2 LVD RELAY RETROFIT KIT (Kit Number: GMDN2206A)
• MTS4 LVD RELAY RETROFIT KIT (Kit Number: GMDN2207A)
CAUTION: The battery installation need a short circuit protection closest to the batteries.
IMPORTANT: The batteries should be installed in the same building and properly ventilated.
3.7.2.1
Service Current Rating
When selecting the AC main service, consider the input current rating of the DC power supply
equipment.
The DC power system has normal loads and start-up loads. These loads are dependent on the number
of Base Radios in the site and the size and condition of the backup battery system. The loads may
differ for the customer designed power systems.
3.7.2.1.1
Power Loads and Heat Dissipation – MTS 400 MHz and 800 MHz
Table 9: Typical Power Loads and Heat Dissipation Values – MTS 400 MHz BR-Arch-1 Configurations
MTS 400 MHz
Configuration
AC
(W)
Heat
AC
(W)
AC
When
Charg
ing
(W)
Heat AC
When
Charg-
ing (W)
DC
-48
V
(W)
Heat
DC
(W)
Comment
TETRA TX 10 W
MTS2 with 1 BR 140 130 520 185 135 125 No combining,
low power PA,
no fans
MTS2 with 1 BR
w. Hybrid
165 155 545 210 160 150 Low power PA,
no fans
MTS2 with 2 BRs 245 225 625 280 240 220 Two TX ant.,
low power PA,
no fans
6802800U74-AP
Chapter 3: Site Preparation
76