Torque Motor Frame; Armature Travel Stop; Coil; Parts Ordering - Fisher 546 Instruction Manual

546 Transducer
March 2015
3. Loosen the four machine screws (key 9, figure 8) that hold the torque motor assembly to the case. Remove the
entire torque motor assembly from the case.
4. Loosen the two flexure pivot screws (key 25) that hold the flexure pivot to the torque motor assembly base.
5. Slide the span adjustment assembly in or out as required. Sliding it in toward the base decreases the span; sliding it
out away from the base increases the span.
6. Tighten the flexure pivot screws. Replace the torque motor assembly, and tighten the screws (key 9, figure 8). Make
sure that the O‐ring (key 37) is in place. Connect the external lead wires, and turn on the air supply.
7. Make final adjustment of the span with the span adjustment screw.

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 happens contact your Emerson Process Management sales office.

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 0.13 mm
(0.005 inches).
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 nylon 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.

Parts Ordering

Whenever corresponding with your sales office about this equipment, mention the serial number of the unit. This
serial number can be found on the nameplate. When ordering replacement parts, also state the complete
11‐character part number of each part needed as found in the following parts list.
Note
In the torque motor assembly drawing (figure 9), there are many shaded key numbers. The shading indicates that these parts
should not be disassembled and that they are not available as individual items. Consequently, no part numbers are shown for
these parts in the Parts List.
WARNING
Use only genuine Fisher replacement parts. Components that are not supplied by Emerson Process Management should
not, under any circumstances, be used in any Fisher instrument. The use of components not manufactured by Emerson
Process Management may void your warranty, might adversely affect the performance of the instrument, and could result
in personal injury or property damage.
16
Instruction Manual
D200108X012