General Inspection; Belt Transmission; Anti-Surge Control; Start-Up Valve - Nederman VAC 20 Manual De Instrucciones

EN WARNING! Risk of personal injuries
Use proper protective equipment when risking
exposure to the dust.
WARNING! Risk of electric shock
Always disconnect the supply voltage before
any servicing, whether mechanical or electrical.
Always lock any maintenance switch in the off
position.
WARNING! Risk of personal injury
Ensure that no vacuum is present in the system
during service.
WARNING! Risk of burn injury
Make sure the unit is cool before undertaking
an inspection to avoid burn. The unit and its
parts can get very hot.
8.1 General inspection
Perform the following general inspection every 500
hours of operation:
• Inspect the incoming connections. Ensure all cables
and hoses are tightly fitted.
• Check for signs of corrosion or other damage.
• Check that the ventilation inlet and outlet of the
unit are clear.
• Check that the ventilation to the room is clear (if
placed indoors).
• Check for dust or collected material inside the unit.
Dust or collected material may indicate a filter mal-
function.
8.2 Belt transmission
Perform the following belt transmission inspection
every 500 hours of operation:
1 Remove the belt guard.
2 Remove the motor side panel for easy access to
the screws that anchor the motor.
3 Replace worn or damaged belts and pulleys.
4 Check the tension of the belt transmission and ad-
just if required.
• The following figures can serve as a guide for all
VAC models and give the force F necessary to
apply to one of the belts as shown in
10 mm slack:
• New belts: F = 24 N (5.4 lbf)
• Used belts: F = 20 N (4.5 lbf)
5 Put back the motor side panel.
6 Put back the belt guard.
New belts are liable to stretch slightly with-
in the first hours of use and are to be more
tightly tensioned than used belts.
20
VAC 20
8.3 Anti-surge control
Every 500 hours check that the unit does not pump
and that the valve 'floats' at varying airflow. See
tion 7.2.4 Adjusting anti-surge control by PLC
tion 7.2.5 Adjusting anti-surge control by optional ad-
aption kit.
8.4 Start-up valve
Perform the following start-up valve inspection every
500 hours of operation:
• Check that the spring holds the valve closed when
the unit is standing still.
• Check that the spring holds the valve closed when
the motor is in Y-mode.
• Check that the valve is open when the motor is in D-
mode.
8.5 Flow restrictor FR 160
Perform the following flow restrictor inspection every
500 hours of operation:
• Check that the flow restrictor is activated when the
motor current tends to exceed the nominal current.
Observe the damper arm at varying airflows. The
variation must cover the range where the restrictor
is activated. If adjustments are necessary, see
tion 8.5.1 Adjusting FR
8.5.1 Adjusting FR 160
Perform the following to adjust the FR 160, see
ure 4:
1 Remove the protection cap, Item 5, covering the
spring.
For fine adjustments: Loosen the screws, Item 7,
to release the disc, Item 8.
• Turn the disc clockwise to increase the airflow
and motor load.
• Turn the disc anti-clockwise to decrease the air-
flow and motor load.
For coarse adjustments: Move the free end of the
spring to the nearest hole on the disc.
2 Measure the motor amperage to check the result-
ing adjustment. This is usually made with a clamp
ampere meter around one of the three incoming
Figure 9 for phases to the motor start and control unit.
• A correct adjustment limits the motor current to
a reading matching the nominal current stated
on the machine tag. A certain over current,
~10%, is accepted just before the restrictor
goes into operation.
3 Lock the disc.
4 Refit the protective cap covering the spring.
Sec-
or Sec-
Sec-
160.
Fig-