PA Fan : Stg-II : Operation & Important

PA Fan : Stg-II : Operation & Important

Important Information :

• Capacity: 700 TPH
• Total Head Devleoped: 1200 mm WC
• Speed: 1480 rpm
• Rating: 2.775 MW and 11 KV
• Full Load current: 169 Amp
• Overload alarm: 180 Amp (TD 20 sec)
• Overload Trip: 192 Amp
• Normal Header Pressure: 820 mm WC
• Current: 90 Amp
• Blade-Pitch: 60 %
• Blade Pitch Locking: 85 %
• Trip : Low =650 mmWC(TD-5 sec) | Low-Low=550 mmWC(Instant)

Prestart checks & Loading:

• Check air path is available .  At least one PAPH is ON and air path of the APH available (APH air I/L & O/L dampers are open), for second PA fan both PAPH must be on 
• Remote / local selector switch of blade pitch mounted on the actuator is selected in remote and the blade pitch is in minimum position. 
• Check that the outlet (discharge) damper is in closed position and in remote 
• Check the PA fan discharge duct drain valve is in closed position .After shut down with
  air preheater water washing this duct drain should be opened first to check any water
  accumulation inside fan casing, before taking PA fan into service.
• Keep cold air gate damper of at least two mills open so that minimum air flow is assured 
•  Start the fan with blade pitch minimum position and ensure opening of discharge damper fully. Then gradually increase the blade pitch position to load the fan.  

STARING OF SECOND PA FAN:-  

• Both PAPH must be ON and its inlet and outlet damper open 
• At least three mills be in service 
• Put blade pitch of 1st PA fan in CAS and PA header pr. In auto with set point 850 mmwcl – 900mmwcl. 
• Start 2nd PA fan and put blade pitch of 2nd PA fan a command of 10-15% as the discharge damper starts opening and close feed back disappears. 

Trip:   

• PA Header Pr Low =650 mmWC(TD-5 sec) | Low-Low=550 mmWC(Instant)
• Vibration: 20 mm/sec for 120 sec OR 28 mm/sec for 5 sec