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Torque Motor Frame
The top pole piece plate (key 50, figure 9) of the
torque motor can become twisted with respect to the
bottom pole piece plate (key 51, figure 9). If this hap-
pens, return the transducer to the factory, service cen-
ter, or contact your Fisher Controls sales office or
sales representative.
Armature Travel Stop
The armature travel stop (key 52, figure 9) must be in
place to prevent overstressing the armature and coil
support (key 41, figure 9) due to over-travel. The
clearance between the armature and travel stop
should be 0.005 inches (0.13 mm).
The two screws at the base of the travel stop can be
loosened if an alignment is necessary.
Coil
The coil assembly (key 42, figure 9) consists of a ny-
lon bobbin wound with wire. The coils are not attached
to the armature itself, and therefore, they must not
touch the armature, or armature movements will be
restricted. If this problem exists, loosen the two
screws that attach each coil assembly to the armature
and coil support. Sight down the armature and realign
the coil assemblies for clearance with the armature.
Tighten the screws.
WARNING
The following maintenance procedures
require that the transducer be taken out
of service. This requires that certain pre-
cautions be taken to avoid personal in-
jury or equipment damage caused by
sudden release of pressure or explosion
of accumulated gas. Prior to mainte-
nance:
Disconnect electrical power before
removing the transducer cover (espe-
cially in explosion proof or hazardous
applications).
Shut off or disconnect pressure
lines to the transducer.
Disconnect any operating lines pro-
viding air pressure, electrical power, or
a control signal to the actuator. Be sure
the actuator cannot suddenly open or
close the valve.
Type 546, 546S, and 546NS
Use bypass valves or completely
shut off the process to isolate the valve
from process pressure. Relieve process
pressure on both sides of the valve.
Drain the process media from both
sides of the valve.
Vent the power actuator loading
pressure and relieve any actuator spring
precompression.
Use lock-out procedures to be sure
that the above measures stay in effect
while you work on the equipment.
Type 82 Relay Removal and
Replacement
Use the following procedure when removing and re-
placing a relay assembly. Refer to figure 10 for key
number locations, unless otherwise directed.
1. Loosen the two mounting screws (key 68), and re-
move the relay assembly from the transducer case
(key 1, figure 8).
2. To install the replacement relay assembly, install
the two relay mounting screws (key 68) into the relay
assembly. Apply lubricant (key 96) to the O-rings, and
make sure the O-rings (keys 72, 73, and 74) are in
place on the relay assembly.
3. Install the relay assembly on the transducer case.
Tighten the mounting screws.
4. With the torque motor installed, apply supply pres-
sure to the transducer case, and check the relay as-
sembly for leaks with a soap solution.
Type 82 Relay Maintenance
Use the procedure below to repair the relay assembly.
Refer to figure 10 for key number locations.
Obtain the relay repair kit listed in the parts list. This
kit provides the parts, alignment tool, and an instruc-
tion sheet used when repairing the relay assembly.
1. Remove the two screws (key 77), valve plug spring
seat (key 64), valve plug spring (key 70) and valve
plug (key 63).
2. Remove the six screws (key 76, not shown) and
separate the relay body (key 60), casing spacer (key
61), and relay casing (key 62) by inserting a screwdriv-
er between the external casting lugs. Twist the screw-
driver to separate parts.
3. Remove the upper diaphragm (key 66), lower dia-
phragm assembly (key 65), and relay spring (key 71).
Clean and inspect relay parts before replacing them.
4. Remove the restriction assembly (key 67) and re-
place the O-rings (keys 74 and 75). Apply lubricant
(key 96) to the O-rings before installing the restriction
assembly into the relay body.
11
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