Curtiss-Wright | EL30 Rev. H PN23942 6/14/16
7
Resolvers
A resolver is a non-electronic device that works like a small
transformer. When rotated, it generates two sine waves that are out
of phase with one another. By decoding these two sine waves, the
amplifier can monitor the direction; revolutions traveled and speed of
rotation of the motor. Each sine wave typically represents one
revolution of the motor, so the amplifier can also use these signals to
know where the motor is within that revolution. By knowing the
motor's position, the amplifier can properly time the supply of current
and voltage to the motor for it to rotate. This process is
commutation.
For the amplifier to properly commutate the motor, it
must have a reference, or zero, point from which to track the motor's
rotation. This reference point is critical, and is provided to the
amplifier through the proper alignment of the resolver to the phases
of the motor during the actuator assembly.
3.0 INSTALLATION AND OPERATION
3.1 Lubrication Requirements
The actuator is shipped from the factory fully greased and ready
for installation. Exlar recommends using Mobilith SHC 220, a high
performance, extreme-pressure grease. The unique physical
properties of the synthetic base oil provide outstanding protection
against wear, rust, corrosion and high or low-temperature
degradation. Mobilith SHC allows for very low starting and running
torque values. Its operating range is minus 40 degrees C to plus
177 degrees C (-40 degrees F to +350 degrees F).
3.2 Mounting Configurations
The EL Series actuators come with a choice of mounting
configurations. The standard configurations available are Rear
Clevis, Front Flange or Threaded Face. Certified drawings are
available from Exlar. General drawings are shown in the Exlar
catalog.
Excessive side load on the output rod of the actuator
will dramatically reduce the life of the actuator and
should be avoided completely. Side load can be caused from
misalignment or loading that is not in line with the actuator
output rod.
