Help me

[AmzG]

An AHU with 20 HP motor is supposed to supply 26,000 cfm cold air to an open office area. During the testing and commissioning stage, it was reported that the air velocity taken at the duct (48”x 36”) is 1,800 fpm. The running current taken was 20.1 A. The motor pulley size is 6” whereas the blower pulley size is 4”. The full load current for that particular motor is 28.1A and the rpm 1455.
Please upgrade the system to achieve the design air flow.

[DEVITG]

You need to change any of the pulley to upward the speed , bigger at the motor , small at the fan , the best option is to use a variable diameter sheave do test up to reach the max motor admissible amperage, after it you can suit with a fixed diameter sheave.

[Samarjit Sen]

Please give the details of the fan/blower. The type and the impeller size. If it is a standard make then the make. Based on these can the fan be upgraded.

[Brian_UK]

An AHU with 20 HP motor is supposed to supply 26,000 cfm cold air to an open office area. During the testing and commissioning stage, it was reported that the air velocity taken at the duct (48”x 36”) is 1,800 fpm. The running current taken was 20.1 A. The motor pulley size is 6” whereas the blower pulley size is 4”. The full load current for that particular motor is 28.1A and the rpm 1455.
Please upgrade the system to achieve the design air flow.

As this appears to be a school question and you being a student playing computer games I would suggest that you read your text books and perform the calculations yourself.

If we tell you then you learn nothing.

However is reply to your question I require first class air tickets and 5 star hotel accommodation and an hourly rate of 250USD. Upon receipt of your instructions I will come out and give you the simple answer.