Guest
I have some questions about the drive arrangements of centrifugal fans. May I know under what conditions/how do we decide when to use what kind of fan arrangements? Such as Arrangement 1, 2, etc. Please advise.
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LinaABC!
What do you actually mean by drive arrangements? (is it like what sort of drive mechanism we have to use viz. direct, belt etc?)
Can you be more specific?
Regards,
Truth: Even the hardest of the problems will have atleast one simple solution. Mine may not be one.
What do you actually mean by drive arrangements? (is it like what sort of drive mechanism we have to use viz. direct, belt etc?)
Can you be more specific?
Regards,
Truth: Even the hardest of the problems will have atleast one simple solution. Mine may not be one.
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Guest
Yah...sort of... Like for example, in the greenheck fan catalog, the first few pages will show differenct kind of fan arrangement, how do we decide which one to use?
(Please refer to page 6 and 7 of this website:
Besides, for belt and direct drive, what are the difference and when to use them?
(Please refer to page 6 and 7 of this website:
Besides, for belt and direct drive, what are the difference and when to use them?
Hello yahoomeil
You should first determine the fan size based on required flow, pressure, rpm. Then look at your physical layout to see what fans would fit, ie: motor location, belt or direct drive, suction and discharge opening locations, etc. Finally look at your required motor horsepower, torque, overhung load, etc. to determine shaft size, number of bearings. By merging all these requirements together they should tell you which of the availble fan or fans will best suit your particular situation.
You should first determine the fan size based on required flow, pressure, rpm. Then look at your physical layout to see what fans would fit, ie: motor location, belt or direct drive, suction and discharge opening locations, etc. Finally look at your required motor horsepower, torque, overhung load, etc. to determine shaft size, number of bearings. By merging all these requirements together they should tell you which of the availble fan or fans will best suit your particular situation.
Yahoomeil!
Your question, I say, is subjective. Generally fans are not tailor made. As Fredb told you have to select a fan based on the flow rate you require. You are lucky enough if you get a fan which suits your requirement or else you have to derate it by using a set of pulleys. Direct drive fans are more efficient than belt driven because of the transmission losses (power). Again the drive arrangement depends on the size of the fan also. (vibrations etc.)
In pharmaceutical air handling units we generally donot prefer direct drive because the motor will come into air path and may contaminate it.
Regarding fan arrangement it depends on, in which direction you require you air to flow. These arrangements will reduce the number of bends you have to use in your ductwork.
Regards,
Truth: Even the hardest of the problems will have atleast one simple solution. Mine may not be one.
Your question, I say, is subjective. Generally fans are not tailor made. As Fredb told you have to select a fan based on the flow rate you require. You are lucky enough if you get a fan which suits your requirement or else you have to derate it by using a set of pulleys. Direct drive fans are more efficient than belt driven because of the transmission losses (power). Again the drive arrangement depends on the size of the fan also. (vibrations etc.)
In pharmaceutical air handling units we generally donot prefer direct drive because the motor will come into air path and may contaminate it.
Regarding fan arrangement it depends on, in which direction you require you air to flow. These arrangements will reduce the number of bends you have to use in your ductwork.
Regards,
Truth: Even the hardest of the problems will have atleast one simple solution. Mine may not be one.
LinaABC
Fan Arragement are defined by AMCA. They determine the bearing location, means of supporting the motor, and how the fan is driven. There are eight standard arragements for centrifugal fans and two for in-line vane axial ones. beside the standard there are some variations.
For Centrifugal Fans:
Arr 1- SWSI, Arr 2-SWSI, Arr 3-SWSI, Arr 3-DWDI, Arr 4-SWSI,Arr 7-SWSI, Arr 7-DWDI, Arr 8-SWSI, ARR 9-SWSI and Arr 10 SWSI.
Must common arr for AHUs is Arr 3 DWDI (double width double inlet)for this fan is located inside the huousing of the AHU. But, for exhaust or supply fans Arr 3- SWSI is the most common.
To select the right application you must decide first if you want direct or belt driven, arr 1 to 3 are for belt or direct althoug they are more suited for belt, because they dont have motor base. Arr 9 is for aplications with belt located outside (it provide a housing for the motor). All the other are for direct drive only.
W1th regard to select direct or belt I am a friend of belts, they are ship, available and easy to balance if you use adjustable pulley. th vibration of the motor is not passed to the wheel and supsecuently the sistem ducts.
I hope this can help you with the other good advices already posted.
Fan Arragement are defined by AMCA. They determine the bearing location, means of supporting the motor, and how the fan is driven. There are eight standard arragements for centrifugal fans and two for in-line vane axial ones. beside the standard there are some variations.
For Centrifugal Fans:
Arr 1- SWSI, Arr 2-SWSI, Arr 3-SWSI, Arr 3-DWDI, Arr 4-SWSI,Arr 7-SWSI, Arr 7-DWDI, Arr 8-SWSI, ARR 9-SWSI and Arr 10 SWSI.
Must common arr for AHUs is Arr 3 DWDI (double width double inlet)for this fan is located inside the huousing of the AHU. But, for exhaust or supply fans Arr 3- SWSI is the most common.
To select the right application you must decide first if you want direct or belt driven, arr 1 to 3 are for belt or direct althoug they are more suited for belt, because they dont have motor base. Arr 9 is for aplications with belt located outside (it provide a housing for the motor). All the other are for direct drive only.
W1th regard to select direct or belt I am a friend of belts, they are ship, available and easy to balance if you use adjustable pulley. th vibration of the motor is not passed to the wheel and supsecuently the sistem ducts.
I hope this can help you with the other good advices already posted.
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