BIG ASS FANS 8'-24' Powerfoil X, Installation Manual

Page: 32 / 72

8’ - 24’ POWERFOIL® X
WWW.BIGASSFANS.COM ©2011 DELTA T CORP. DBA BIG ASS FAN CO. ALL RIGHTS RESERVED
26
WWW.BIGASSFANS.COM ©2011 DELTA T CORP. DBA BIG ASS FAN CO. ALL RIGHTS RESERVED
8’ - 24’ POWERFOIL® X
Delta Secondary
There are many different arrangements available for industrial and commercial power distribution in the United States. The three most
common are:
• 480/277V Three Phase (Wye secondary) , which provides 480V between phases, and 277V from each phase to Neutral / Ground.
• 208/120V Three Phase (Wye secondary) , which provides 208V between phases, and 120V from each phase to Neutral / Ground.
• 240/120V Three Phase (Delta Secondary) , which provides 240V between phases for three phase loads, 120V from phase “A”
and “C” to Neutral / Ground, and 208V from phase “B” to Neutral / Ground as shown below. In this transformer arrangement, phase
“B” is commonly referred to as a “Wild Leg” or “High Leg,” and shall be marked accordingly with an orange finish or other effective
means per NEC 110.15.
20
8V
24
0V
12
0V
12
0V
24
0V
24
0V
“A” Phase
“C” Phase
“B” Phase
Neutral / Ground
CAUTION: Care must be taken when connecting to a Three phase 240/120V Secondary as shown above. All
fan controller models rely on internal references made between each incoming phase and ground. To prevent
nuisance tripping such as Overvoltage and Undervoltage faults, the following recommendations should be
followed:
• 200-250 Three phase fan controllers should be connected so that the High leg, or phase “B,” terminates on
“L2” of the fan controller’s input power terminals.
CAUTION: Installations utilizing supply transformers with a 480V Delta Secondary (ungrounded, corner
grounded, open) MUST be avoided. Proper fan operation cannot be guaranteed due to a lack of proper phase to
ground voltage references.