Group 14 Linear Valve Actuators
Suggested Specifications
Use the following as a guideline when specifying Beck Group 14 linear
valve drives.
Basic Drive Unit
Control drive shall have integrated electronics and be able to operate in
ambient temperatures of -40°F. (-40°C.) to 185°F. (85°C.).
Control drive shall be furnished with a ___ 120 volt AC, single phase, __
(50 or 60) Hz, synchronous motor. Motor shall be capable of
withstanding 60 starts / stops per minute or a temporary stall condition
without overheating. Design of the motor shall be such that electrical
and thermal overloads are not required.
Motor bearings shall be maintenance-free. Motor shall be non-coasting
with instant magnetic braking, and shall be self-locking and self-releasing
without the use of a separate brake winding, mechanical brake
or worm gear mechanism. Control drive shall be designed to stay in
place upon loss of power and shall be capable of holding a load equal to
at least 200% of the model’s rated output. The drive motor shall be a
TENV with Class H insulation.
Control drive shall be rated for ____lb thrust output. Stall thrust shall be
self-limiting, not exceeding two and one half times the rated thrust;
torque switches shall not be required. Drive shall ___ (extend or retract)
valve stem on increasing signal, with timing of __ seconds per inch of
travel. Gear train shall have high efficiency spur gears constructed of
heat treated alloy steel or ductile iron only. Drive shall include Tight-
Seater™ coupling for positive valve shutoff. Gear train parts shall be
lubricated with a premium, heavy-duty, lithium-based lubricant. No oil
baths shall be used for lubrication. Control drives shall be able to
operate in any mounting orientation.
Two SPDT over-travel limit switches shall be provided for over-travel
protection. In addition, the drive shall have ____ (none, two, four)
auxiliary SPDT switches which are infinitely adjustable over the full
range of travel. Switches shall be rated for 6 amps at 120 volts AC.
Drive shall have integral mechanical stops capable of limiting travel of
the drive and load, with or without the drive motor.
A low-speed, disc-type motor Handwheel shall permit manual operation
of the drive without electrical power and without a declutching
mechanism.
A five-position, drive-mounted electric Handswitch shall be provided to
permit local electrical operation of the unit for control adjustment or
operation on loss of control signal. With the Handswitch in AUTO mode,
drives shall respond to control signals automatically.
Enclosure shall be totally enclosed, cast, weatherproof, dust-tight, NEMA
4 construction. All field connections shall be made at one terminal
compartment. Separate conduit entrances shall be available for power
and control wiring.
Drive Control Options
Modulating mA or V dc Analog Control Input:
Drive shall provide modulating control through an integral, digital
control module which positions the drive in proportion to the (___ mA
range or ___ V dc range) control input signal.
The control module shall be capable of initiating shaft movement in
steps down to 0.1°.
Standard control features should include:
- Field-configurable, pre-determined action upon loss of input signal
- Stall protection
- Split signal operation for control of multiple drives
- External position feedback signal
Modulating Direct AC Control:
Drive shall be operated by direct AC control power either from an
automatic controller or by manually operated switches, with continuous
positioning capability over the range of operational limits of valve travel.
Drive shall be capable of starting and stopping instantaneously for highresolution positioning.
Multi-Position Direct AC Control:
Drive shall provide ___ (3 to 6) discrete positions upon closure of an
automatic controller or by manually operated switches, with provision
for adjustable predetermined position settings, and have a positioning
repeatability of 0.1% over the range of operation.
Open / Close Direct AC Control:
Drive shall provide two discrete positions upon closure of an automatic
controller or by manually operated switches and have a 0.1% position
repeatability with end-of-travel limits adjustable over the full range of
travel of the drive.
Position Feedback Specification
Drive shall be equipped with a contactless position sensing device and
be capable of providing an isolated feedback signal with a 4–20 mA or
1–5 V dc range. The sensing device shall have infinite resolution.
|
