Flow Restrictor Oil; Fan Bearings Temperature; Fan Bearings; Motor Bearings - Nederman VAC 20 Instruction Manual

8.5.2 Flow restrictor oil
There is a risk that the restrictor starts self-oscillating
when the oil level is low. This can cause damage to the
restrictor and the fan.
Perform the following flow restrictor oil level check
every 500 hours of operation:
• Turn the restrictor shaft rapidly by hand all the way
to the outer end position when the vacuum unit
stands still, see Figure 11.
• If the resistance is uneven: Check the oil level with
a suitable probe. Top up the oil to a level 70-80
mm over the piston surface if necessary. Use auto-
matic transmission fluid.
• If the resistance is even: The oil level is correct.
8.6 Fan bearings temperature
Perform the following fan bearings temperature con-
trol inspection every 500 hours of operation:
• Check the bearing temperature on the two fan bear-
ings, see Figure 1. Normal temperature range is 50–
90°C (122–194°F).
• If the temperature is above 95°C (203°F) ensure
the following:
• The ambient air is cool. See
for information.
VAC 20
Section 5.2.1 Location
• The openings for cooling and ventilation are free.
See Section 5.2.1 Location
• The belt is properly fitted. See
transmission for information about maintenance
of belts.
• The bearings are in good condition. See
tion 8.8 Motor bearings
aged or worn bearings.
8.7 Fan bearings
Change the fan bearings within 15,000 hours of op-
eration, or sooner if there is reason to suspect dam-
aged bearings. See mounting instruction MI12-002 for
more information.
8.8 Motor bearings
The recommended intervals for replacing perman-
ent bearings or re-greasing the grease nipple can be
found on the motor data label or motor manual.
The operating time before service depends on size,
environmental and operating conditions. As the fol-
lowing values are guidelines at normal operation:
• Replace permanent bearings before 15,000 hours of
operation.
• Re-grease the bearings at least every 4,000 hours
of operation.
for information.
Section 8.2 Belt
Sec-
on how to replace dam-
21
EN