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3kW FM Mosfet
Transmitter
ET3000
is the new top FM broadcast amplifier designed by Elenos.
It’s the smallest and lightest 3Kw amplifier in the
world, and changes the conception of all 3kw Mosfet
transmitters.
The Philips Mosfet BLF278 on its 12 RF modules are used at
250W power output in low-stress conditions. Each module is
running at 90% rated power offering a better MTBF.
To reduce the harmonic current emission to the main, the 3
AC/DC switching power supply units are equipped with PFC
(Power Factor Corrector.
The current sharing between PSU’s is performed by a
robust digital control that works at any RF output power
level. The good matching between the PSU’s ensures a
greater reliability and allows higher output power to be
reached. The PSU’s are also overheating temperature and
short circuit protected. MOV devices also protect the
equipment from any low energy fast transients in the
mains. E 3000 can operate with one power supply a
reduced power level.
Available single-phase or three-phase.
ICE FET ® technology and high-efficiency heatsink
The innovative ELENOS ICE FET® technology,
together with a high-efficiency heatsink (ELENOS patented
design), lead to a considerable heat dissipation
reduction, so that it’s more reliable.
A dedicated algorithm optimises the efficiency at all
output power levels, automatically adjusting Mosfets’
drain voltages and bias of MOSFETs.
New RF combiner ELENOS ®
The E 3000 uses a polygonal combiner (ELENOS
patented design), instead of traditional RF power
combiners.
In traditional combiners, the combining of 12 power
modules uses a considerable space for multiple
transmission lines with a loss in the overall RF power.
This power loss generates heat which is detrimental to the
overall efficiency.
The patented ELENOS system uses polygonal type combiner in
a single jump, thereby reducing the power dissipated by
approximately 50% compared with the traditional couplers -
whilst maintaining a high level of insulation between the
inputs, guaranteeing perfect operation under any fault
condition on the MOSFET’s.
An additional impedance transformer stage, located before
the output low pass filter, better suppresses the
harmonics.
Measurements, Controls and Protections
5 microcontrollers with CISC and RISC architecture
guarantee that it never stops working.
The control software is based on a proprietary real-time
multitasking operating system and uses parallel
programming techniques and fuzzy logic to optimise the
operational parameters.
Algorithms are implemented for efficiency maximization,
cooling adjustment, automatic output power derating in
case of faults or overheating.
All parameters of the equipment are controlled by
amplifier’s CPU board who interacts with them to ensure
perfect operation always. The information are processed by
a bus IEE485 in a numeric form, avoiding problems and
measurement errors that might occur from interferences,
electromagnetic fields, noise etc.
The distributed intelligence control logic manages:
- DC
current of each 250W RF module
- 9
temperature probes, placed at various points of the E
3000 , to get a detailed thermal mapping of the
amplifier
- the VSWR
fast protection circuit which controls the RF stages
bias
- the soft
start algorithm that reduces the thermal stress of the
MOSFETs in the event of start-up at temperatures below
zero degrees.
- fans
speed to optimise the air flow depending on the
effective heat exchange requirements of the system
- measurement
of the air input temperature
- measurement
of the current, voltage and temperature of each power
supply unit
- measurement
of the direct and reflected output power
- calculation
of the RF efficiency
- alphanumeric
display, incremental encoder and signalling LED’s
- telemetries
and SMS
Detailed design
The traditional thermo-magnetic switch has been replaced
by a hydro-magnetic switch with an extremely high
stability at temperatures of between -40° and + 85°C in
order to best protect the equipment.
6 very high efficiency, low noise DC fans, of the
“ultra-long life brushless” type to provide 800
m3/hour air flow and more than 50,000 hours of operating
life.
Telemetry and SMS
By using a GSM modem and any DOS or Windows communication
programme (Telix, Procomm, HyperTerminal) it is possible
to remotely control and interact with E 3000.
Up to 5 preset mobile phone numbers are notified through
SMS in case of alarm if the equipment is connected to a
GSM modem.
E 3000 also has I/O logic commands for connection
to change-over equipments and/or external telemetry.
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