Dwyer 275 - Manual (Page 2)

Series 275 Installation
Series 275 is designed for rotary motion valves such as Dwyer
Instruments ball and butterfly valves using rack and pinion, scotch yoke
or complex type actuators whose stem is rotated 90°. Series 275 p -
ositioners consist of the following components:
1. Series 275 main body
2. Fork lever and lever spring to attach on actuator
3. 1 bracket
4. Four hex bolts M8x1.25P
5. Four M8 plate washers
Installing Series 275 with bracket
Series 275 is supplied with a standard bracket. The bracket consists of
two parts and is used with a NAMUR shaft. The bracket is assembled in
the factory based on 0.79˝ (20 mm) of actuator stem height. If the
actuator stem height is higher, such as 1.18˝ (30 mm), or 1.97˝ (50 mm),
reassemble the bracket adjusting to the actuator stem height. Refer to
the table below to check hole positions.
Ex) If H is 30 mm, A-L should be locked in H:30 hole, B-L in H:20,30, A-
R in H:30, and B-R in H:20,30 with bolts.
1. Typical actuator stem heights (H) are 0.79, 1.18 and 1.97 inches (20,
30, and 50 mm). After checking H, assemble brackets following
previous guidelines. The bracket is set at 0.79˝ (20 mm) in the
factory.
2. Attach bracket to the actuator using hex bolts. The diameter of the
bracket bolt holes are 0.24˝ (6 mm). Use spring washers or thread
lock compound so the bolts will not be loosened by vibration or
impact. The direction of the bracket varies by operating conditions,
but the normal direction is depicted in the following picture. That is,
when the piping of actuator and Series 275 is as shown in direction
A, the bracket hole and indicator attached on the bottom of the Series
275 main shaft should be mounted in the same direction.
3. Set the rotation position of actuator stem as the initial zero point,
which is 0% stroke. For a spring return type actuator, the actuator
stem is always rotated to the zero point without supply pressure,
making it easy to check the zero point. If the actuator is double-
acting, check whether the rotation direction of the actuator is
clockwise or counter-clockwise or check the rotation direction of the
actuator using supply pressure.
4. Set the actuator stem as the initial zero point and install a fork lever
as shown in the following picture. Confirm the position of initial zero
point when actuator stem is turned clockwise and counter-clockwise.
Installation angle of fork lever should be about 45 degrees based on
the linear shaft. But the angle is not related to NAMUR shaft.
page 2
Series 275 installation example
Series 275 installation example of fork lever
Series 275 installation example of Namur shaft
Bracket assembly method by actuator stem height H
Actuator stem
height (H)
20 mm
30 mm
50 mm
Markings of bolt holes
A-L
H: 20
H: 30
H: 50
B-L
H: 20, 30
H: 20, 30
H: 50
A-R
H: 20
H: 30
H: 50
B-R
H: 20, 30
H: 20, 30
H: 50
20
Actuator Stem (H)
Actuator
Attachment direction of bracket and actuator
Direction A
450
450
Counter-Clockwise
Clockwise