Wiring, General, Transformer – Dodge EN221 User Manual
Page 7: Three-position (floating) control (24 vac), Dodge engineering & controls, inc, Installation
 
 
Dodge Engineering & Controls, Inc. 
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Installation
EN221 and EN310 Non-Spring Return Electronic Actuators
Settings: 
Offset U0 = 2, Span: ∆U = 16V 
Umin = minimum control signal 
Umax = maximum control signal 
100
0
∆
U (16 V)
Y
U
(v)
Y
S
(%)
2
18
10
U
min
U
max
50
U
o
EA0412R1
Figure 19. Example.
Wiring
• All wiring must conform to NEC and local codes
and regulations.
• Use earth ground isolating step-down Class 2
transformers. Do not use auto transformers.
• The maximum rating for a Class 2 step-down
transformer is 100 VA. Determine the supply 
transformer rating by summing the total VA of all 
actuators and components used. It is 
recommended that no more than 10 actuators 
are powered by one transformer. 
CAUTION: 
Do not parallel wire EN221/EN310 
actuators with any other type of 
actuator, including EN221/EN310 
actuators with date codes earlier than 
501. 
WARNING:
Mixed switch operation is not permitted 
to the switching outputs of both 
auxiliary switches (A and B). 
Either AC line voltage from the same 
phase must be applied to all six outputs 
of the dual auxiliary switches, or UL-
Class 2 voltage must be applied to all 
six outputs. 
NOTE: With plenum cables, only UL-
Class 2 voltage is permitted.
Three-Position Control
If the damper blades turn counterclockwise (CCW) 
to open, reverse the 6 and 7 wires at the controller 
(see Table 1). 
EA0683R1
NEUT
EARTH GROUND
ISOLATING CLASS 2
TRANSFORMER FOR
24 Vac POWER
120 Vac
7 (ORANGE)
6 (VIOLET)
1 (RED)
24
Vac
Figure 20. Three-Position Control.
UL Doc. No. 129-272
EAI/EN-7
Dodge Engineering & Controls, Inc.
Rev. 5, Jan., 2005