232
6 Fans and Flow Control Devices
0
1000
2000
3000
4000
5000
6000
7000
8000
0
2 0
4 0
6 0
8 0
P (Pa)
Q (m 3 s -1 )
System
2.130 kW
130 kW
2.150 kW
150 kW
6.2.13 Fans Operation
When a three-phase motor is started with a direct-on-line motor starter, a peak of
current consumption takes place. This peak can reach 4–10 times higher than the
motor running current and may cause a voltage dips in the grid. For this reason, the
following starting systems are usually adopted, namely:
• Star-delta starter,
• Auto-transformer starter, and
• Soft starter.
The manufacturer determines the type that best suits the motor for each model of
starter.
As far as maintenance is concerned, modern fans have electronic devices to
protect the motor. This includes thermistors to control temperatures, accelerometers
to control vibrations and Petermann probes to detect the stall effect.
In addition, the following recommendations are established:
• In order to avoid bearing failure, the alignment between the motor and fan shafts
must be checked at least once every six months.
• The oil tanks should be checked at the frequency indicated by the manufacturer.
The same applies to the greasing of the fan parts.
• The blades must be checked annually to avoid material deposits and wear.
• A complete overhaul of the bearings is recommended every year.
• In general, action should be taken on the fan if it shows: abnormal vibrations,
excessive noise, high-energy consumption or low performance.
6 Fans and Flow Control Devices
0
1000
2000
3000
4000
5000
6000
7000
8000
0
2 0
4 0
6 0
8 0
P (Pa)
Q (m 3 s -1 )
System
2.130 kW
130 kW
2.150 kW
150 kW
6.2.13 Fans Operation
When a three-phase motor is started with a direct-on-line motor starter, a peak of
current consumption takes place. This peak can reach 4–10 times higher than the
motor running current and may cause a voltage dips in the grid. For this reason, the
following starting systems are usually adopted, namely:
• Star-delta starter,
• Auto-transformer starter, and
• Soft starter.
The manufacturer determines the type that best suits the motor for each model of
starter.
As far as maintenance is concerned, modern fans have electronic devices to
protect the motor. This includes thermistors to control temperatures, accelerometers
to control vibrations and Petermann probes to detect the stall effect.
In addition, the following recommendations are established:
• In order to avoid bearing failure, the alignment between the motor and fan shafts
must be checked at least once every six months.
• The oil tanks should be checked at the frequency indicated by the manufacturer.
The same applies to the greasing of the fan parts.
• The blades must be checked annually to avoid material deposits and wear.
• A complete overhaul of the bearings is recommended every year.
• In general, action should be taken on the fan if it shows: abnormal vibrations,
excessive noise, high-energy consumption or low performance.