Alpha Technologies GMX-915 - Manual (Page 47)

7 017-932-B0-002, Rev. B
5.0 Operation, continued
5.5 Providing Power via External Source
In the event of an extended utility failure, an external AC or DC power source can provide
backup power to the system. The backup power source allows the power supply to continue
charging the batteries, and ensures uninterrupted service to the network. Follow the
procedures outlined in the documentation and/or connection procedures listed below.
5.5.1 DC Powering
A convenient method of providing backup DC power to the network is the AlphaGen
Portable Generator. On loss of commercial AC power, the existing battery string(s)
immediately supply voltage to the inverter. After some point of battery discharge, an
operator can deploy the portable generator to the site to supply power to the DC bus.
Refer to the AlphaGen Portable Generator Operator’s Manual, Alpha P/N 041-028-
B0, for complete connection and operation information.
5.5.2 AC Powering
Should it become necessary to power your network with a portable AC generator,
truck-mounted AC generator, or truck-mounted inverter, the procedures below must
be followed for the protection of service personnel and system powering equipment.
Connection Procedure:
1. Determine if there is output power to the cable system by reading the Smart
Display. If there is still power to the system then check the battery voltage on the
Smart Display. If the battery voltage is greater than 34.5Vdc (3-battery system)
then approximately one hour remains to complete the changeover to generator
power before the cable system loses customer power. If the battery voltage is
less than the previous numbers, move rapidly as there is not much time until
system failure. Use extreme caution, there are dangerous voltages in the system
that can shock you or damage the cable amplifiers.
2. Verify the AC Input breaker from the utility powering system is in the OFF
position. This ensures that if power returns suddenly, both you and the system
will not experience a surge in power, and that when you connect the generator, it
does not put AC voltage back onto the power lines.
3. Properly ground the generator. This is accomplished by connecting a #6 AWG
wire from the grounding lug on the output panel of the generator to either a
driven ground rod or the strand ground on the pole to which the power supply is
mounted. If working with a ground-mounted power supply, locate the grounding
point inside the enclosure and clamp on to that point.
Grounding of the generator is mandatory for safety and for proper operation of the power
supply.
WARNING!
. After properly grounding the generator, unplug the power supply from the
convenience outlet inside the enclosure and plug the power supply input cable
into the generator output. An NEC or UL approved extension cord must be used.