26
McQuay IM 672-7
Operation
Operating Limits
Do not exceed the operating limits in
Table 10
. A fan wheel
operated beyond the rpm and temperature limits shown can
suffer permanent distortion or fracture. The resulting
unbalance can cause severe unit vibration.
Figure 39: Torque for FC Variable Inlet Vanes (in–lb)
Figure 40: Torque for AF Variable Inlet Vanes (in–lb)
Table 10: Unit Sizes 003 to 035
Fan operating limits
Forward curved—housed
Dia.
9 × 4 9 × 7 9 × 9 10.62 12.62
15
18
20
22.25 24.50
Max. rpm
Class I
N/A 2189 2223 1934 1614 1328 1155 1050 944
858
Max. rpm
Class Il
2244 2854 2896 2518 2091 1725 1450 1200 1030
910
Airfoil—housed
Dia.
13.22 14.56 16.19 19.69 21.56 24.00
Max. rpm
Class I
3000 3000 2300 2000 1700 1500
Max. rpm
Class Il
4335 3918 3457 2858 2427 2255
300
250
200
150
100
90
80
T
orque (in–lb)
350
400
450
500
600
650
700 750 800 850
1000
1500
Fan speed (rpm)
500
400
350
300
250
200
550
900
FC20.00
FC36.00
FC33.00
FC30.25
FC27.62
FC25.00
FC22.38
300
250
200
150
100
90
80
70
60
50
750 800 850 900
1000
1500
2000
Fan speed (rpm)
40
35
30
AF24.00
AF21.56
AF19.69
AF16.19
AF14.56
AF13.22
2500
3000
3500
4000
4500
350
400
450
T
orque (in–lb)
Table 11: Unit Sizes 040–090
Fan operating limits
Forward curved—housed
Dia.
20
22.38
25
27.62
30.25
33
36
Max. rpm Class I
1010
930
790
690
650
600
560
Max. rpm Class Il
1281
1178
1011
910
835
763
715
Airfoil—housed
Diameter
20
22.25
24.5
27
30
33
36.5
Max. rpm Class I
2077
1875
1691
1479
1328
1209
1073
Max. rpm Class Il
2703
2413
2199
1928
1730
1579
1401
