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52
Selection Process
Selection Process
Fan Performance Chart
Example 1 :
The following are the design requirements for FUD30B unit:
Model:
FUD30B
Supply Air Quantity
=
4200
CFM
External Static Pressure
=
180
Pa
Step 1: From the fan curve (at 4200 CFM),
Standard operating system;
Total Static Pressure
=
320
Pa
Internal Static Pressure
=
171
Pa
External Static Pressure
=
149
Pa
External Static Pressure of 149 Pa did not fulfill the design requirements.
Step 2: Therefore at 4200 CFM and 180 Pa External static pressure,
Total Static Pressure
=
171 + 180
Pa
=
351
Pa
Step 3: From the fan curve, the design requirement calls for RPM about 800, whereas the unit can only deliver
RPM about 760 under the same CFM. Therefore, it is necessary to resize the pulley sizes.
From the table:
Motor pulley
=
80
mm
Blower pulley
=
160
mm
Motor RPM
=
1405
In order to obtain 800 RPM, we recalculate the new blower pulley as:
(while maintaining the motor pulley)
Db
=
80 x (1405/800)
= 140.5 mm
The nearest pulley size will be a diameter of 140mm
Recheck, with Db =
140mm
Blower pulley
=
1405 x (80/140)
= 803
We thus need to change the blower pulley from 160mm to 140mm in order to obtain the higher operating
static pressure.
Step 4:
When the pulley is changed, the V-belt length must be rechecked. We have for horizontal air throw
configuration:
V-belt length, L
=
2C + 1.57 (Db + Dm)
=
(2 x 340) + 1.57 (80 + 140)
= 1025.4mm
We thus can use a belt with a length of
1030mm
where,
C
=
distance between the centres of the two pulleys
Db
=
diameter of blower pulley
Dm
=
diameter of motor pulley
Step 5:
From the fan curve, we can also notice that the motor power input has increased. At the new operating
point, the power is approximately 1.25 kW.
By applying a safety factor of 1.2 to account for losses, we calculate that the motor power input requirement
should be = 1.25 x 1.2 =
1.5 kW
Thus, the existing motor is still sufficient to drive the blower with the smaller 140mm pulley.
Summary:
i) Fan motor kW
=
1.5
kW
ii) Blower pulley diameter
=
140
mm
iii) V-belt size
=
1030
mm
Содержание FUD Series
Страница 2: ......
Страница 4: ...Table of Contents ii...
Страница 71: ...67 Fan Performance Chart...
Страница 76: ...72 Fan Performance Chart...
Страница 77: ...73 Fan Performance Chart...
Страница 78: ...74 Fan Performance Chart...
Страница 79: ...75 Fan Performance Chart...
Страница 80: ...76 Fan Performance Chart...
Страница 81: ...77 Fan Performance Chart...
Страница 82: ...78 Fan Performance Chart...
Страница 88: ...84 Fan Performance Chart...
Страница 124: ...120 Wiring Diagrams Model FWC09 12 14 16C Without Controller Model FWC03 04 06 14 16 18 20G MSP...
Страница 125: ...121 Wiring Diagrams Model FWC08 10 12G MSP Model FWC02 03 04 06 08 12G EC LSP MSP...
Страница 126: ...122 Wiring Diagrams Model FUD20B Model FUD25B...
Страница 127: ...123 Wiring Diagrams Model FUD30B...
Страница 131: ......