CFMI PROPRIETARY INFORMATION
CFM56-5B TRAINING MANUAL
EFG
FUEL FLOW TRANSMITTER
The second type of fuel flow transmitter consists of a housing containing a swirl generator, a free-spinning rotor and a turbine, which is restrained by a spring attached to the housing.
Two permanent magnets are fixed, 180 degrees apart, at the forward and aft end of the rotor.
With each complete revolution of the rotor, the forward end magnet induces an electrical pulse in a small coil mounted on the outer wall of the housing. This is known as the ‘start’ pulse.
The aft end magnet aligns with a signal blade fixed on the turbine. As the magnet passes the signal blade, another pulse is induced into a second, larger coil, which is also on the outer wall of the housing. This is known as the ‘stop’ pulse.
One ‘start’ pulse and one ‘stop’ pulse are generated through the coils at each revolution of the rotor.
If the rotor could spin without fuel flow, the start and stop pulses would occur simultaneously.
When the fuel starts flowing, the rotor spins at a speed that is proportional to the fuel flow and the signal blade on the turbine, restrained by the spring, begins to deflect along the path of rotation.
The stop pulses now begin to occur after the start pulses.
As the mass flow (weight) of fuel through the transmitter increases, the turbine deflects further and further, and the time difference between the start and stop pulses increases proportionally.
It is this time difference which is measured by the ECU, and converted to Fuel Flow and Fuel Used values, which are then made available to the A/C for cockpit indication.
The operating range of the fuel flow transmitter output is from 0 to 170 milliseconds, which corresponds to a fuel flow range of 0 to 27000 lbs/hr.
EFG
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CTC-201-285-01
EFFECTIVITY
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ALL CFM56-5B ENGINES FOR A319-A320-A321
ENGINE SYSTEMS Jan 03
CFMI PROPRIETARY INFORMATION
CFM56-5B TRAINING MANUAL
EFG
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EFG
FUEL NOZZLE FILTER
EFFECTIVITY
73-11-45 Page 1
ALL CFM56-5B ENGINES FOR A319-A320-A321
ENGINE SYSTEMS Jan 03
CFMI PROPRIETARY INFORMATION
CFM56-5B TRAINING MANUAL
EFG
FUEL NOZZLE FILTER
The fuel nozzle filter is installed near the servo fuel heater at 8 o’clock and attached to the fuel flow transmitter.
The fuel nozzle filter collects any contaminants that may still be left in the fuel before it goes to the fuel nozzle supply manifold.
EFG
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CTC-201-283-00
EFFECTIVITY
73-11-45 Page 3
ALL CFM56-5B ENGINES FOR A319-A320-A321
ENGINE SYSTEMS Jan 03
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