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16.1 CAPACITORS (SINGLE PHASE MOTORS ONLY)
Capacitors which are physically small in size, are normally mounted on the motor during manufacture. Larger capacitors are
supplied separately and must be fitted remotely from the motor. Capacitors associated with fans and motors designed for use
within hazardous areas must be located outside the hazardous area.
WARNING!
Be aware that electrical components can operate at high temperatures. Keep Flammable Materials away from
these components and their connections. Whilst it is extremely rare, the possibility of component malfunction
must be taken into consideration when installing and operating the product.
16.2 OVERHEAT PROTECTION
Motor overheat protection (if fitted) can be enabled on all single-phase and three-phase motors and can be achieved by using
either thermostats or thermistors. Protection device connected options are listed below:
- Where single-phase or three-phase motors have a full load current of up to and including 6.3 Amps: thermostats can be
wired in series. Where the unexpected re-closure of self-resetting of a thermal cut-out can cause a hazard, or is prohibited by
regulation, it must be connected into a control circuit that will not allow the fan to restart until the circuit has been manually
reset.
- Where single-phase or three-phase motors have a full load current above 6.3 Amps: thermostats must be wired to separate
terminals (K – K) within the terminal box; they operate by opening and closing, depending on the temperature and must be
wired to directly control the motor start contactor. Where thermistors are used these must be wired to separate terminals
(S –S) within the terminal box; they operate by changing their resistive value with temperature and must be wired to control
the motor start contactor via a suitable relay.
NOTE!
When the fan is intended to be used for emergency high temperature operation, overheat protection must be by
passed in the event of an emergency (see Section 16.5).
NOTE!
When a motor cools down, an over-heat protection thermostat will reset. However, to maintain safe operation,
the motor must not be allowed to start until the motor start contactor is manually reset.
16.3 BEARING TEMPERATURE AND VIBRATION MONITORING SENSORS
If monitoring sensors are fitted into the fan control system, then they must be wired to automatically switch the fan off if a fault
occurs, or to provide a fault indication. If the fan is automatically switched off by a monitoring sensor the control system (via
a PLC for example), must ensure that the fan is fully isolated from the electrical supply, so that it will not automatically reset
and re-start. If the fan is designed for emergency use, then the control system must ensure that all monitoring devices are
overridden so that the fan is immediately switched on during an emergency situation (see Section 16.5).
16.4 ANTI-CONDENSATION HEATER
If monitoring sensors are fitted into the fan control system, then they must be wired to automatically switch the fan off if a fault
occurs, or to provide a fault indication. If the fan is automatically switched off by a monitoring sensor the control system must
ensure that the fan is fully isolated from the electrical supply, so that it will not automatically reset and re-start. If the fan is
designed for emergency use, then the control system must ensure that all monitoring devices are overridden so that the fan is
immediately switched on during an emergency situation (see Section 5.5).
16.5 EMERGENCY-USE FANS
Where the fan assembly is designed for emergency-use (smoke-extraction) at high temperature, the temperature / time
capability of the product will be shown on a special label adjacent to the main nameplate. We recommend that an automatic
control system, or a clearly marked remotely sited emergency-use switch, is fitted to override all other switches and controls,
so that the fan is immediately switched on when an emergency situation occurs. The only exception is where a matched and
certified Frequency Converter drive is fitted, as this can remain "in-circuit" if appropriately selected. If you require further
information or advice, please contact Woods Air Movement directly. Also refer to sections 1 to 11 of this document for more
detailed guidance related to our HT Series fans..
Appropriately rated high temperature cable must be used to supply power to the fan, while the electrical supply must be from a
guaranteed or separately maintained source to enable that the fan continues to run during the emergency condition. After such an
emergency the fan must be removed, refurbished or safely disposed of (see Paragraph 20), and replaced as necessary.
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16.6 FANS WITH ATEX OR HAZARDOUS AREA MOTORS
Fans with ATEX/hazardous area motors fitted are designed for use in locations where fumes, dust or flammable/explosive gases
may be present. Installation should be carried out by qualified and competent personnel. Special care must be exercised when
connecting such units to an electrical supply to ensure that a secure and safe ATEX/hazardous area connection is achieved.
Great care must be taken to ensure that cable gland or conduit thread standards match their corresponding connector thread
standard, so that the entire installation achieves the required level of protection. Long cased, fully ducted fans fitted with
ENV89 motors are not fitted with an external duct-mounted terminal box. The electrical supply cable must be routed through a
conduit entry in the fan duct and connected directly into the motor terminal box before the fan is fully installed (i.e. before the
inlet and outlet ducts are fitted).
Any electrical control gear (including a capacitor in the case of single-phase motors) must be located outside the hazardous
area, if these items are not certified for use in that zone. The motor must not be allowed to become coated with dirt/dust, etc.
as this reduces motor cooling capability and will consequently raise the temperature of the motor carcase, which could then
create an additional risk.
16.7 SWITCH ON
Before switching on, confirm that the electrical supply is fully compliant with the requirement of the motor as detailed on the
motor or fan nameplate, that the fan is correctly installed, all component parts and fixings are secure, safety guards are in place
and no loose items or associated equipment are present in the vicinity.
Immediately after switch-on check that the rotation direction is correct. For three phase motors, if the rotation direction is
incorrect, then this can be rectified by interchanging any two incoming phase connections of the electrical supply at the motor
terminal block. For single-phase motors, the motor winding leads should be interchanged at the motor terminal block. In the
case of BT and CT motors, these are identified by black and red coloured wires. In the case of other motors these wires are
labelled "U1" and "U2".
Check the assembly for smooth, low vibration running, and check that the current consumption is within the full load current
specified on the nameplate. The fan motor must not be repeatedly or rapidly switched on and off as this could cause
overheating of the motor or its associated wiring connections.
17. MAINTENANCE
DANGER!
No maintenance work must be attempted before switching off and completely isolating the fan assembly, its
anti-condensation heater (If fitted), and its controls, from all electrical supplies and allowing the rotating parts of
the fan to come to rest.
WARNING!
Before entering the area ensure that all fumes, dust, toxic emission, heat etc. have dispersed from the local
environment, and the fan blades are not likely to freely rotate.
WARNING!
All lifting aids used during maintenance, and all lifting points utilised, must be adequately certified to carry the
weight of the equipment being lifted. (See paragraph 15).
WARNING!
Always wear appropriate protective clothing (including hard hats, eye protectors and ear defenders etc.) when
working in the vicinity of the fan assembly.
Fan assembly maintenance must be carried out by appropriately qualified and competent personnel using the correct tools
and equipment. A regular maintenance schedule should be established, and a record kept. Recommended maintenance
intervals are given within Table 1 (page 17).
Where the environment is particularly dirty, it may be necessary to reduce maintenance / service intervals. Internal and external
fan surfaces may be cleaned with low pressure clean water and non-abrasive additives. Water or liquid cleaning agents must
not be directed at motor drain holes, as this could cause liquid ingress.
After maintenance has been conducted and before the fan is re-started, always ensure that there are no loose items of
equipment present in the vicinity of the fan, that all safety guards, chains or steel ropes, etc., are properly secured into their
original location, and that any temporary device used to stop the fan blades from rotating has been removed.
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