User Manual

Worcester Actuation Systems Series 75 Electric Valve Actuator FCD WCAIM2013-01 - 08/04
4
pin(s). Add the two additional Belleville washers with
their larger diameter sides touching each other. Add the
self-locking nut to the stem and tighten while holding the
stem fl ats with wrench. Tighten until Belleville washers are
fl at, the nut will “bottom”, and then back nut off
1
⁄
1
⁄
1
3
⁄3⁄
turn.
The two additional Belleville washers and the self-locking
nut are included in the mounting kit.
a
CAUTION:
The self-locking stem nut is diffi cult to
tighten, and must fully fl atten Belleville washers
before backing off.
For 2" 59, H71, 82/83, and 2½" 45, 82/83 Series valves
and valves 3" and larger with square stem, remove handle
assembly (if any), retaining nut, stop and stop screws.
Replace with valve stem spacer or, if valve has graphite
stem packing, with two Belleville washers (except 8", 10"
82/83 and 10" 51/52) and replace retaining nut. NOTE:
Belleville washers are installed with larger diameters
touching each other. Using a wrench to prevent stem from
turning, tighten retaining nut until stem packing is fully
compressed or Bellevilles, if used, are fully fl attened, then
back off nut
1
⁄
1
⁄
1
6
⁄6⁄
turn. Excessive tightening causes higher
torque and shorter seal life.
NOTE:
Large valves with V51 high cycle stem packing
option installed, identifi ed by two belleville washers
installed and handle assembly, stop and stop screws
removed, and 818/828 Series valves do not require stem
area disassembly.
For ½"–2" 94 valves, remove handle (if any). For 3"–6" 94
and 2"–8" E818/E828 valves, remove handle assembly,
stop, and spacer (if any). Do NOT remove gland plate or
gland bolts.
For 2"–8" 818/828 valves, remove handle assembly, locking
plates and hardware, and stop screw (if any). Do not
remove stop plate (2"–6" sizes) or spacer (8" size).
c. Center coupling on valve stem.
d. Lower mounting bracket/actuator assembly over coupling
and onto valve, making sure that male actuator shaft
engages slot in coupling.
e. Secure bracket to valve using cap screws and lockwashers,
or bolts and nuts provided in mounting kit. Tighten
securely. For small size top mount style valves, bracket
nameplate will be to side of valve.
f. Install set screws (if any) in the coupling and tighten
securely.
C. Series 75 actuator in modulating control service and interface with
PC and/or computer.
1. Series 75 actuators can be used for modulating control service
operated directly by programmable controller or computer
under specifi c conditions as follows:
a. To achieve stable control, an actuator with a longer cycle
time is recommended.
b. To eliminate overheating from frequent startups, 75% or
100% duty cycle actuators are required.
c. To eliminate problems with interfacing, and to protect
the output circuitry of the controller, use Worcester I-75
interface board.
2. Alternately a controller coupled with a Series 75 actuator must
have:
a. Two outputs (one to open, one to close) per actuator being
controlled.
b. Nine amp minimum output rating.
c. Buffered Output – Resistor and capacitor wired in series
across each triac.
If a controller output does not meet these requirements,
two relays (one to open, one to close) may be installed
between controller and each actuator. Failure to observe
these precautions will result in controller output damage.
Electrical Installation and
Adjustment
a
CAUTION:
It is recommended that the actuator motor not be
driven directly from the PLC output. The inrush current/back
EMF can destroy the PLC output card triacs if they are not of
suffi cient rating. As a minimum these should be rated 800 volt,
12 amp triacs. In addition to these ratings, snubber circuits
should be utilized to help protect the triacs. This applies to
120 VAC motors only. 240 VAC motors should never be driven
directly from a PLC output card.
A. To gain access to terminal strip, it is necessary to remove the
actuator cover.
10-2275 (General Purpose)
Loosen cover screws and lift cover
from unit.
10-2375 W, X and Z
Remove declutch knob screw and lift knob
from shaft. Remove the two cover screws from cover (the other