Fisher® 4800 pages

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480 Series Actuators

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D100091X012

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Product Bulletin

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61.2:480

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February 2013

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Fisher® 480 Series Yokeless Piston Actuators

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Fisher 480 Series actuators are yokeless piston

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actuators that are used in either throttling or on-off

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applications with ball valves, butterfly valves, louvers,

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dampers, and rheostats. They require pneumatic

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pressure loading from double-acting positioners

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(Fisher 3570) or from on-off loading and unloading

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devices.

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Features

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■ Actuator Versatility—Actuator with or without

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positioners and snubbers is available in an

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assortment of sizes, stroking speeds, thrusts, and

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travels to handle most control requirements.

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■ Compact Design—Yokeless construction permits a

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low-profile assembly by allowing close coupling to

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the control device; either through a bracket or, with

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some versions, by direct mounting on a bonnet

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flange.

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■ Wide Range Supply Pressure Capability—The

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cylinder (and 3570 positioner if used) can operate

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with supply pressures as low as 2.4 bar (35 psig) or

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as high as 10.3 bar (150 psig).

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■ Long Stroke—Actuators have maximum rated

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travels of up to 206 mm (8.125 inches).

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■ Positioner Versatility— Positioner/actuator action is

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easily reversed in the field with no additional parts.

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Positioner sensitivity, travel span, and travel starting

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point are factory set and need to be reset only if

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operating conditions have changed or if the

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positioner has been reversed. See figure 1.

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Fisher 480-15 Piston Actuator

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Actuator Frequency

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Response

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Figure 3 shows how various size actuators respond

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when the input supply pressure is cycled at small

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amplitude (3 to 5 percent) and increasing frequency.

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Assume the cycling supply pressure and the

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movement of the actuator rod are represented by sine

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waves. As the actuator rod is forced to move faster, its

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motion begins to fall behind the input in both time

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(shown as phase lag) and amplitude (shown as

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normalized gain). Both of these parameters are

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affected by the inertia of the actuator and,

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consequently, changes are more pronounced in the

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larger constructions.

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EMERSON

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www.Fisher.com

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Process Management

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