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5. CONNECTION
The wiring to the fan must be in accordance with the connection diagram in the terminal box.
Fans are designed for a 3-phase electrical supply. On commissioning, the rotation of the impeller should always be checked to
ensure that it is running in the correct direction.
6. CABLE
Suitable fire-resistant cable must be used between the main supply, starter controls and the fan. The mains supply must be from
a guaranteed or separately maintained source, to enable the fan to continue running under emergency conditions. Fan housing-
mounted terminal boxes for all HT fan specifications are designed to accommodate Mineral Insulated supply cables.
7. CONTROL
High Temperature rated fans can either be run Direct-on-Line during their emergency [high temperature] operation, or via
an approved frequency converter, which has been selected in accordance with EN12101-3:2015. Where required, a voltage
waveform filter must also be fitted between the frequency converter and the fan drive motor. If in doubt, please seek advice
from Woods Air Movement USA (sales.us@flaktgroup.com).
Our HT fans can be soft-started, and speed controlled when operating in a normal ventilation mode. Use of non-approved
drives is permitted as long as the drive is by-passed from the control circuit once the fan is running at full speed. Frequency
converters (also known as Variable Frequency Drives or VFDs) must not be located in the same fire compartment as the
extract fans. They should instead be located within a suitable fire protected compartment, remote from the fan. VFDs must
be connected to the fans using appropriate HT cable for the application and where required with screened cables to minimize
the impact of EMC affects. VFDs should also be fitted with appropriately selected voltage waveform, RFI or Harmonic filters,
depending on the application.
Over-heat protection, vibration sensors, bearing sensors and frequency converter motor over-heat protection circuits must
be disabled during emergency mode if provided.
8. MAINTENANCE - HT FANS
For normal operation and planned preventative maintenance please refer to sections 17 and 18.
AT 3 MONTHLY INTERVALS WHEN FANS ARE NOT NORMALLY RUN
If the fan is intended for emergency use only, the resistance of its windings to earth should be measured (at 500v dc).
If the Resistance value is found to be less than 10 MΩ (Megaohm), then the motor should be dried out and re-checked.
Run the motor for at least 15 minutes to prevent hardening of the grease and to minimize bearing corrosion issues.
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