Page 241 - FanPedia - By Twin City Fan and Blower

FAN-PEDIA

Published by TECHNICAL DESCRIPTIONS

Twin City Fan & Blower

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Anti-backspin devices
Prevent the rotor from freewheeling in reverse when not in operation. They are typically mounted
between the bearings on overhung wheel designs and on a shaft extension on the non-drive end of
center hung wheel designs.

Arrangement 1 SWSI — Single Width, Single Inlet (Centrifugal)
Arrangement 1 is usually belt driven. The wheel is overhung on the shaft, i.e., mounted at the end of
the shaft. The two fan bearings are mounted on the bearing pedestal, out of the airstream, which
makes them ideal for high temperature or contaminated air applications. Belt driven configurations
offer performance flexibility. The motor can be mounted in any of the four AMCA standard motor
positions, W, X, Y, or Z.

Motor Position restrictions based on Discharge
BHD discharge (motor interferes with outlet opening of housing)
 CW rotation: Motor position “Z” NOT ALLOWED
 CCW rotation: Motor position “W” NOT ALLOWED
TAD discharge (motor interferes with outlet opening of housing)
 CW rotation: Motor position “W” NOT ALLOWED
 CCW rotation: Motor position “Z” NOT ALLOWED
THD discharge (Height restriction – motor may not fit below the discharge)
 CW rotation: Motor position “W”
 CCW rotation: Motor position “Z”

*On Arrangement 1 fan the motor will fit if pedestal is lengthened to accommodate motor.

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