Battery System Grounding; Checking Grounding Connections; Power Supply Connections; 48 Vdc Input Power And Backup Battery Charging Connections - Motorola MTS LiTE Installation, Configuration And Basic Service Manual

6802800U74-AN
Chapter 4: Hardware Installation
4 Using the M10 bolt provided, secure the cabinet ground wire to the M10 nut on the junction
panel.
5 Ground connections should be checked after installation.
See Recommended Torque on page
4.5.2.1

Battery System Grounding

Ground the battery cabinet (if used) in accordance with manufacturers instructions and any applicable
local regulations.
4.5.2.2

Checking Grounding Connections

Perform this procedure to ensure adequacy of the cabinet-to-facility grounding (earth) connections.
Procedure:
1 Install the earth cable between the building earth and the earth point on the cabinet.
2 With a Milliohmmeter, check that the earth connection between the cabinet and the building
earth in the room is 0.1 Ω.
4.5.3

Power Supply Connections

One of the following power supply connections is required for the MTS:
• DC in/out – within -41 VDC to -60 VDC – for MTS 4 two connectors are available
• AC in – within 100 VAC to 240 VAC (nominal values) – for MTS 4 two connectors are available
4.5.3.1

-48 VDC Input Power and Backup Battery Charging Connections

The -48 VDC connectors are used for:
• Supplying the MTS with power in the DC only mode – in DC only mode the MTS takes the power
from a separate -48 VDC facility power system
• For charging backup batteries in the AC mode
CAUTION: An external disconnect device is required on the DC power supply line.
CAUTION: If the DC input on the station is connected to backup 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. 20A/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 40A/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)
NOTICE: Figure 31: -48 VDC Connection on the MTS 2 Junction Panel on page 101
32: -48 VDC Connections on the MTS 4 Junction Panel on page 101
of the MTS Junction Panel. There may be small differences in older configurations.
10
0
143.
and Figure
depict the newer version