| FAN PERFORMANCE CURVES The following fan curves were developed from test data taken in
accordance with AMCA standards. Belt losses are not included.
FAN SELECTION EXAMPLE
PROBLEM:
Select SB ventilating unit and motor horsepower to deliver,
6,000 SCFM at 1.50" w.c. total static pressure. Desired motor type is single speed,
1800 RPM, dripproof.
SOLUTION:
- check fan performance curves for smallest SB model which
will handle the specified air flow and total static pressure. This proves to be the SB-115
- Locate 6,000 SCFM on the horizontal axis of the SB-115 fan
performance curve and move vertically to the point of intersection with the
1.50" w.c. total static pressure line. This defines the operating point : fan speed
will 920 RPM and the motor will draw 3.5 HP. The next larger size motor, 5HP,
is required.
- From the Reference Table on this page, we find that the 5
HP, 1800 RPM dripproof MOTOR HAS A 184T frame size. This size is smaller than the
maximum motor frame size of 213T shown on SB-115 fan performance curve, so selection is
acceptable.
- From the SB-115 performance curve, the fan outlet velocity
is shown to equal SCFM/2.28. At the operating point of the selected unit, the outlet
velocity is 6,000/2.28 or 2,632 FPM.
MOTOR FRAME SIZE PERFORMANCE TABLE
| MOTOR
HP |
MOTOR
TYPE |
| 1800
RPM Dripproof or TEFC |
1800/900
RPM
One Winding |
1800/1200
RPM
Two Wining |
| Dripproof |
TEFC |
Dripproof |
TEFC |
| 1.5 |
145 T |
145 T |
145T |
145 T |
145 T |
| 2 |
145 T |
145 T |
145 T |
182 T |
182 T |
| 3 |
182 T |
182 T |
182 T |
184 T |
184 T |
| 5 |
184 T |
184 T |
184 T |
215 T |
215 T |
| 7.5 |
213 T |
213 T |
215 T |
254 T |
254 T |
| 10 |
215 T |
215 T |
215 T |
256 T |
256 T |
| 15 |
254 T |
256 T |
256 T |
284 T |
284 T |
| 20 |
256 T |
284 T |
284T |
286 T |
286 T |
| 25 |
284 T |
286 T |
286 T |
324 T |
324T |
| 30 |
286 T |
286 T |
324 T |
324T |
326T |
| 40 |
324 T |
324 T |
326T |
326T |
364T |
| 50 |
326 T |
326 T |
364 T |
365T |
365T |
| 60 |
364 T |
364 T |
365 T |
404 T |
404 T |
| 75 |
365 T |
405 T |
405 TS |
405 T |
405 T |
| 100 |
405T |
405 T |
444T |
444 T |
445 T |
NOTES :
1. All motors three phase.
2. Motors less than 1.5 HP have frame sizes that will fit
within any SB model ventilating unit cabinet.
3. SB - 240 maximum frame size, 405T. For larger frame
sizes consult factory. |
