Use the following as a guideline when specifying Beck Group 31 rotary drives.
Basic Drive Unit
Control drive shall have integrated electronics and be able to operate in ambient temperatures of -40°F. (-40°C.) to 150°F. (85°C.).
Drive to provide output torque of ___ (15 or 30 lb-ft) to move output shaft ___ (CW/CCW) on increasing signal, with timing of ___ seconds.
Drive enclosures shall be made of precision-machined, aluminum alloy castings to provide a rugged, dust-tight and weatherproof enclosure, mountable in any orientation. Enclosure shall be rated for NEMA 4. The drive shall have mechanical stops capable of limiting travel of the drive and load, with or without the drive motor; two field-adjustable limit switches shall permit setting end-of-travel limits for the driven load. The unit shall have mechanical shaft position indication.
Gear train shall have precision-cut, heat-treated alloy steel and ductile iron gears only.
Drive energized by 120 V ac 50/60 Hz, single-phase no-burnout, noncoasting motor capable of 60 starts per minute. Design of the motor shall be such that electrical and thermal overloads are not required. The drive motor shall be a TENV with Class H insulation. The stall current shall not exceed rated full load current.
Motor/gear-train combination shall be self-locking and self-releasing without the use of a separate brake winding or mechanical brake. The drive shall be capable of maintaining position when the motor is deenergized, with a minimum of 150% of rated torque.
Drive shall be furnished with two auxiliary switches in addition to end-of- travel limit switches. All switches shall be form C rated for 1 amp at 120 V ac.
Drive train parts shall be lubricated with 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.
Drive shall be furnished with integral manual Handwheel. Handwheel shall be non-rotating during automatic operation and shall not require the use of a declutch mechanism.
DRIVE CONTROL OPTIONS
Modulating mA or V dc Analog Control Input:
Drive shall provide modulating control through an integral, solid-state electronic signal receiver which positions the drive in proportion to the 4–20 mA range or 1–5 V dc control input signal. The electronic module shall have a deadband of 1.0% of span with sensitivity of 25% of deadband. The signal receiver span shall be nominally adjustable from 50% to 125% of the 4 V span, with the zero adjustable up to 120% of the 4 V span.
Drive shall be furnished with an integral manual electric Handswitch to permit local electrical operation for control adjustment or emergency operation on loss of control signal.
Drive shall be equipped with a stall protection function which turns off power to the motor and is activated when the drive is unable to achieve the desired position within approx. 70 seconds. Stall protection shall be activated by either a jammed condition or loss of AC power. Relay contacts will open for optional remote stall annunciation.
Position Feedback Module:
Modulating drives shall be equipped with an electronic position sensing module for remote position indication, providing a 4–20 mA or 1–5 V dc feedback signal. The feedback module shall have infinite resolution, with a linearity error of less than ±1% span over full drive travel.
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 a range of operational limits for forward and reverse operation. Drive shall be capable of starting and stopping instantaneously for high resolution positioning. Drive shall include an electronic position sensing module for remote position indication generating a standard 4–20 mA or 1–5 V dc output signal.
Open / Close Direct AC Control:
Drive to provide open/close operation to preset travel limits upon closure of an automatic controller or by a manually operated switch, and have a 0.3% position repeatability, with end-of-travel limits adjustable over the full range of travel of the drive.