2020.05 / f
12
Electric Power Generation
Installation and maintenance
LSA R/H 49.1
Low Voltage Alternator - 4 pole
4528 en -
4.4 - Air/water heat exchanger
• Description of the cooler
losses (mechanical, ohmic...). The exchan-
ger is located on the top of the machine.
Normal operation :
the air is pulsed by a fan fixed to the
synchronous machine shaft. The air goes
through the exchanger, rendering its
calories.
AIR / WATER double tube exchanger:
The double-tube technique keeps the
cooling circuit from being affected by
possible water leakage. The double tube
provides a high safety level. In case of
leakage, the water goes from the inside of
the internal tube to the coaxial space
between the two tubes. The water is drained
axially to a leakage chamber where it may
activate a sensor.
An exchanger is comprised of a fin-tube
block containing:
- a steel frame,
- a fin-tube block crimped mechanically to
the tubes.
The tube bundle is roll-expanded in the end
plates (parts 3 and 4).
The water distribution in the tubes is
provided by two removable water boxes
(part 5). A water box is equipped with collars
for fitting the inlet and outlet lines. Neoprene
seals ensure the watertightness between
the water boxes and the end plates.
AIR / WATER single tube exchanger:
An exchanger is comprised of a fin-tube
block containing :
- a steel frame,
- a fin-tube block crimped mechanically onto
the tubes.
The tube bundle is roll-expanded in the end
plates.
The water distribution in the tubes is
provided by two removable water boxes.
One water box is equipped with collars for
fitting the inlet and outlet water lines.
Neoprene seals provide watertightness
between the water boxes and the end plates.
• Maintenance of the water-cooler
The frequency of cleaning operations
depends essentially on the purity of the
water used. We recommend a minimum of
one inspection per year.
Stop the machine.
Cut off the power supply by isolating the inlet
and outlet lines, and drain the water.
Disconnect the leak sensor (option with
double-tube cooler), and make sure that
there are no leaks.
Remove the water boxes on each side of the
machine.
Rinse and brush each water box.
Note : do not use a hard wire brush as this
will remove the protective oxidation layer
which has formed on the surfaces of the
water boxes.
Clean each tube with a metal scraper ; rinse
in soft water.
Keep the leakage chamber dry (double-tube
water-cooler only).
• Leak detection for a double-tube
exchanger
If a leak is detected, it is necessary to
ascertain its origin immediately and repair it.
Remove the two water boxes, apply a slight
positive pressure in the leakage chamber,
thus between the two tubes (only concerns
the double-tube coolers).
If a tube is damaged : plug it at BOTH ends.
Use a tapered plug.
The plug should preferably be made of salt-
water resistant aluminium bronze or of a
synthetic material.
1 - Single internal tube
2 - External tube with
internal grooving and
with external fins
3 - Internal plate
4 - External plate
5 - Outside wall of the
pressure tank
6 - Flow of water or
liquid leaks
