COBHAM SEA TEL 9711IMA-70, Installation Manual

Page: 166 / 178

Dometic AC Transformer Upgrade
Page 2 of 7
Document No
134069 Rev-B
1.0 Purpose:
This procedure identifies the steps required to mount and electrically connect the
buck transformer for the Dometic air conditioner (Sea Tel part Number 123494-2 or 123496-2)
to a XX97 series stand or under an 81 inch radome.
2.0 Scope:
This Procedure / Work Instruction applies to any installation of the Dometic Air
Conditioner to accept alternating current voltages greater than 230 volts, 50 Hertz.
3.0 Methodology:
Cobham SATCOM, Marine Systems (Sea Tel) offers a compact marine grade
air conditioner for Sea Tel’s larger radomes. These air conditioners, Sea Tel part number
123494-2 and 123496-2, are manufactured by Dometic and are powered by 200 to 230 volts
alternating current, 50 or 60 Hertz frequency.
In certain instances, the supply voltage from the installation’s switchboard may exceed 230
volts alternating current. Often, for installations with 50 Hertz frequency on the alternating
current, the supply is nominally 240 volts. When this happens, it can cause a fault in the air
conditioner protective circuitry and the air conditioner will shut down.
To correct this issue, Sea Tel has worked with the air conditioner manufacturer to find a
solution allowing the air conditioner to work with supply voltages between 200 and 250 volts
alternating current at either 50 or 60 Hertz frequency. This solution involves introducing a
buck (voltage-reducing) transformer between the circuit breaker for the air conditioner and
the air conditioner itself. This transformer is equipped with a switch which allows the
transformer to be activated when the supply voltage exceeds 230 volts alternating current.
The buck transformer is equipped with a by-pass switch for 60 Hertz operation, though it is
not necessary to upgrade 60 Hertz units. This by-pass switch should also be used if the
operating voltage at 50 Hertz is less than 215 volts alternating current (though, again, this
upgrade is not necessary in those instances).
4.0 Responsibilities:
4.1
Sales Representative. A Representative from the Sales Department shall
interface with the customer and determine if the Dometic transformer upgrade is
required for each installation. A sales order shall be created.
4.2
Service Manager . The Service Manager shall determine if support is required
from the Sea Tel Service Department based on the customer’s technical ability.
4.3
Service Technician . If required, a Service Technician shall be assigned to
complete the installation.
5.0 Safety:
5.1
All work to be completed by trained Sea Tel personnel or authorized dealer in
accordance with all local, state, and federal regulations and all shipboard safety
protocols as applicable.
EAR Controlled - ECCN EAR99