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505429-JTG-F-1010
74 Johnson Controls Unitary Products
Drive Selection
1. Determine Upflow or Horizontal supply duct Application.
2. Determine desired airflow.
3. Calculate or measure the amount of external static pressure.
4. Using the operating point, determined from steps 1, 2 & 3, locate this point on the appropriate supply air blower
performance table. (Linear interpolation may be necessary.)
5. Noting the RPM and BHP from step 4, locate the appropriate motor and/or drive on the RPM selection table.
6. Review the BHP compared to the motor options available. Select the appropriate motor and, or drive.
7. Review the RPM range for the motor options available. Select the appropriate drive if multiple drives are available for the
chosen motor.
8. Determine turns open to obtain the desired operation point.
Example
1. 3250 CFM
2. 1.4 iwg
3. Using the supply air blower performance table below, the following data point was located: 1100 RPM & 1.8 BHP.
4. Using the RPM selection table below, Model X is found.
5. 1.8 BHP exceeds the maximum continuous BHP rating of the 1.5 HP motor. The 2 HP motor is required.
6. 1100 RPM is within the range of the 2 HP drives.
7. Using the 2 HP motor and drive, 1 turn open will achieve 1128 RPM.
Airflow Performance
Example Supply Air Blower Performance
(CFM)
Available External Static Pressure - IWG
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP RPM BHP
Standard 1.5 HP & Drive High Static 2 HP & Drive
3000 696 0.9 757 1.1 822 1.2 891 1.3 961 1.3 1019 1.5 1077 1.6 1135 1.8
3250 729 1.1 790 1.3 855 1.4 924 1.5 984 1.6 1042 1.7 1100 1.8 1159 2.0
3500 766 1.3 826 1.5 892 1.6 953 1.6 1010 1.8 1069 1.9 1127 2.0
RPM Selection
Unit Model HP
Max
BHP
Motor
Sheave
Blower
Sheave
6 Turns
Open
5 Turns
Open
4 Turns
Open
3 Turns
Open
2 Turns
Open
1 Turn
Open
Fully
Closed
X
Std. 1.5 1.73 1VL40 AK69 N/A 690 743 796 849 902 955
HS 2 2.30 1VL40 AK56 N/A 863 929 995 1062 1128 1194