8’–24’ POWERFOIL
®
X2.0 & POWERFOIL
®
X2.0PLUS FANS
27
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8’–24’ POWERFOIL
®
X2.0 & POWERFOIL
®
X2.0PLUS FANS
Delta secondary
CAUTION: Care must be taken when connecting to a three-phase 240/120V secondary as shown below. 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, 200–250V, 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: Avoid installations utilizing supply transformers with a 480V delta secondary (ungrounded, corner grounded,
open). Proper fan operation cannot be guaranteed due to a lack of proper phase-to-ground voltage references.
There are many different arrangements available for industrial and commercial power distribution in North America. The most common
are the following:
•
575V/330V Three-Phase (Wye Secondary)
. Provides 575V between phases, and 330V from each phase to Neutral/Ground.
•
480V/277V Three-Phase (Wye Secondary)
. Provides 480V between phases, and 277V from each phase to Neutral/Ground.
•
208V/120V Three-Phase (Wye Secondary)
. Provides 208V between phases, and 120V from each phase to Neutral/Ground.
•
240V/120V Three-Phase (Delta Secondary)
. 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.
Electrical Installation (cont.)
20
8V
24
0V
12
0V
12
0V
24
0V
24
0V
“A” Phase
“C” Phase
“B” Phase
Neutral / Ground
