Product Manual for Tornado X and Tornado XR
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48 Volts
0.5 Amps
0.6 Amps
56 Volts
0.4 Amps
0.5 Amps
Table 2: Current draw assuming 20% Transmitter Duty cycle and 80% Efficiency of Power Supply
8.2.3.3 Starting Current
As long as the power supply can supply the static power it should be able to provide sufficient current during start-
up.
8.2.3.4 Supply Polarity (Isolated Power Supply)
In the Base station radio, both the positive and negative connections of the power supply are isolated from the
case and other circuitry. This is not so for the Remote radio which has a non-isolated power supply.
The standard DC power cable supplied with an RU is twin 1.5mm (16AWG), approximately 2m long, terminated at
the RU end with a Phoenix Contact MSTB 2,5 HC plug. This cable is wired to pins 1 (positive) and 2 (negative) of
the plug, which employs screw terminal contacts.
Pin 1 – Positive (Red)
Pin 2 – Negative (Black)
Power supply connector
8.2.3.5 Grounding
The radio unit case must be grounded through an external earth strap. Generally, this is done to the local rack
frame, which in turn should be part of a well-designed station grounding system. This internal grounding is
designed for EMC and transient protection currents. The RU casting is tapped to take a M4 x 8mm screw for
grounding purpose.
8.2.3.6 Supply Noise
Regardless of the EMC provisions in the equipment, power wiring from the DC source should not be shared with
other equipment that may introduce excessive noise. Nor should the power cables to the RU be run alongside
cables that connect to other equipment that may produce high current noise or transients, e.g. power relays.
8.2.3.7 Operating from AC Mains:
AC-DC ‘desktop’ power supplies are available from Mimomax with the required power.
8.2.3.8 Choice of power supply cable size
The table below indicates the maximum length of cable that can be used for given supply voltages and cable sizes.
It also includes the maximum loop resistance, so that other combinations can be checked.
Cable length was calculated for 80% power transfer efficiency (or 10.5 volts at the radio, in the case of a 12V
supply) with a 68-watt load and supply Vmin. The value used for resistivity of copper was at 70 Celsius. This table
is a guide only. Always check the cable manufactures data before detailed engineering.
Supply voltage
