Table of Contents
Advertisement
17.1 FIXINGS
It is essential to ensure that all fan assembly fixings are secure. When examining and checking the security of fixings during
routine maintenance (see Table 1 Items 10 and 11), any fixings which have locking devices fitted or are painted over, need not be
disturbed if it can be seen that they are secure. Any locking devices that are disturbed during maintenance must be discarded and
replaced with new identical devices. Thread forming screws must have locking compound applied when being reused. Any fixings
which have no locking devices fitted and are not painted over, must be checked at 95% of their original torque setting to ensure
that no unnecessary disturbance of the fixing has occurred. See Figure 13 (Page 24) for torque setting details. If in doubt, please
contact Woods Air Movement for advice in relation to specific fixing torque values.
17.2 LUBRICATION
In addition to routine maintenance, motor bearings will, in the longer term, require attention. If motor bearings are greased
through extended lubricators, then the required quantity of grease must periodically be applied in accordance with information
stated on the fan or motor nameplate and/or as per any instructions provided. A fully compatible grease type must be used,
and it is essential that all traces of water and dirt are removed from around the grease points and that a clean grease gun is
used. It is only necessary to apply a small amount of pressure when injecting the specified quantity
of grease into the re-gearing point. If grease injection requires the maintenance engineer to apply a high pressure, then
the cause should be investigated. Grease points are generally located close to the fan duct-mounted terminal box.
Where motors require re-lubrication, a separate instruction is normally issued with each fan/motor configuration.
This gives details of lubrication intervals and well as the type and quantity of grease to be used. If further details are required,
please contact Woods Air Movement directly.
17.3 INFREQUENT USE
If the fan assembly is used less frequently than once a month, or is designed for emergency-use only, the following additional
maintenance procedures must be carried out, and a record kept:
- Resistance of motor windings to earth, must be measured (at 500V dc) each month. If these readings are less than 10 MΩ
(Megaohm), the motor must be dried out in a warm airflow (typically at 40°C) and re-checked before running the motor.
- The fan should be operated between 15 and 30 minutes each month ensure that correct lubricant conditions are
maintained within the bearings (i.e. to prevent grease hardening).
- An 'emergency-use' system should be run continuously for a minimum of fifteen minutes each month. The test should
not only confirm that the fan operates correctly but must also ensure that the emergency use control system overrides all
other control devices (except where matched Frequency converters are used)
(see Paragraphs 1 to 11 and 16.5 for more information).
- If anti-condensation heaters are fitted, check each month that they automatically switch on
(i.e. they are drawing current) when the motor is switched off.
18. OVERHAUL / EXTENDED MAINTENANCE
Advice on motor overhaul procedures, bearing /seal replacement, motor replacement, motor rewinding, spare parts, condition
monitoring, vibration analysis, refurbishment, etc. is available from Woods Air Movement service centre in Colchester.
For emergency use fans we recommend that motor shaft seals and bearings must be replaced after 20,000 hours or
5 years of normal operation whichever occurs first.
After 40,000 hours of running, we strongly recommend that a qualified and competent electrician performs a motor "health
check" (as described within section 8, Fault finding) to determine the motor insulation condition.
If motor insulation readings are less than 10 MΩ (Megaohm), available when the fan is used during an emergency operation,
to ensure that adequate insulation life is available should the fan be required for emergency operation, then we recommend
that the motor must be replaced with a new motor which has been manufactured in accordance with current requirements as
stated within the EN12101-3 specification.
NOTE!
When dealing with High Temperature Smoke Extract fans, only an authorised company may undertake
the maintenance. Failure to do so may invalidate any warranty and CE / UKCA Certification. The motor
manufacturer's specification sheets are available through Woods Air Movement. After overhaul/extended
maintenance the fan assembly must be correctly installed back into its original position in accordance
Paragraphs 12, 13, 14 and 15 of this document.
After conducting overhaul /extended maintenance the fan assembly must be correctly installed back into its original position
in accordance Paragraphs 12, 13, 14 and 15 of this document. For advice on "switching on" after maintenance, please refer to
paragraph 16.7.
14
19. FAULT FINDING
Please refer to the safety warnings ("attention" items) stated within paragraph 17.
NOTE!
Routine maintenance procedures detailed in Paragraph 17, and Table 1 (page 17), of this document are
designed to help keep your fan operational and fault free.
19.1 ELECTRICAL
Check that electrical connections to the fan are secure and are in accordance with the wiring connection diagram.
Check that the voltage applied at each fan terminal is as specified on the fan nameplate and is balanced. Measure the current
on each phase (one phase in the case of single-phase motors) of the motor in turn and check that the current consumption is
within the full load current specified on the motor or fan nameplate.
Measure each motor winding to earth, and between each winding, using a 500V dc insulation tester. If the reading is less
than 10 MΩ (Megaohm) the reason is likely to be dampness within the motor. To dry out the motor place it in a warm dry
airstream (typically at 40°C) and regularly monitor the motor until the insulation reading is restored to 10 MΩ (Megaohm) or
greater. If the reading remains at less than ten, then this could indicate that a break-down in motor winding insulation has
occurred, which may require the motor to be either rewound/overhauled (standard temperature machines) or replaced with a
new motor which been manufactured in accordance with current requirements as stated within the EN12101-3 specification.
(smoke extraction machines).
If a smell of burnt motor insulation is detected, then please seek immediate advice from Woods Air Movement UK (Colchester
Office).
19.2 MECHANICAL
Check that there are no obstructions to the motor shaft or impeller blades, that the blades are clean, and that there are
no loose components, items or debris in the vicinity.
Rotate the motor shaft by hand. Investigate any grinding noises, internal chaffing, rubbing or stiffness. If any of these defects
are observed, this may indicate that bearings require lubrication or replacement.
Ensure that all fixings are secure and tightened to the correct torque values.
20. DISPOSAL
Metal components of the fan/motor should be segregated and separately recycled. The following items of material should be
safely disposed of in accordance with local health and safety regulations:
- electrical lead coverings,
- motor winding insulation materials,
- bearing lubricant,
- motor/fan terminal block,
- paintwork,
- plastic parts,
- packing materials,
- silencer infill (Note that a face mask and gloves must be worn when handling the infill. If the infill is particularly dry or is
damaged it should be damped down before disposal),
- Thermal motor packing seal (bifurcated fans).
15
Hide quick links:
Advertisement
Table of Contents
