2Dan Eslinger Assistant Technical Director Seattle Repertory Theatre Motor Winch PhysicsDan EslingerAssistant Technical DirectorSeattle Repertory Theatre
3Sample Winch Design Application: Wagon: 3000#Max velocity: 3.5 ft/secAcceleration: 2 ft/sec2Rules of thumb:Velocity: 3 ft/sec standard top speed4 ft/sec for fast applicationsAcceleration: 1 ft/sec2 – 4 ft/sec2Decide how long for it to reachtop speed.Casters: 6” diameter soft rubber running on a flat wood deck.
4Wagon: 3000# v: 3.5 ft/sec a: 2 ft/sec2 6” diameter soft rubber casters First, find the Force required to move the wagon:Forcetotal = Faccel + Ffriction + FliftN: normal force, perpendicular to motion, here: the loadµr: caster’s coefficient of rolling frictionhard rubber on wood: 0.003”soft rubber on wood: 0.008”rc: radius of casterDouble the friction to be safe.
5Wagon: 3000# v: 3.5 ft/sec a: 2 ft/sec2 6” diameter soft rubber casters Force to move wagon: 346.3#Size the Motor (hp):Round up to 3 hp motor.sample: 1750 rpmSize the Drum: at least 30 times the cable diameter.Choose 8” diameter drum.
6Wagon: 3000# v: 3.5 ft/sec a: 2 ft/sec2 6” diameter soft rubber casters Force to move wagon: 346.3# 3 hp motor rpm ’ per drum rev.Size the Reducer & Sprockets: match desired top speed (3.5 ft/sec)Choose 15:1 reducer.reduction needed in sprocketsDrum sprocket teeth = x reducer sprocket teeth.e.g. 12 teeth on reducer & 14 teeth on drum.
7Wagon: 3000# v: 3.5 ft/sec a: 2 ft/sec2 6” diameter soft rubber casters Force to move wagon: 346.3# 3 hp motor rpm ’ per drum rev.15:1 Reducer 12 teeth – 14 teeth sprocketsVerify Amount of Torque:T: torque in ft lbsForce is great enough to move wagon!
8Compact Manual Winch Loren Schreiber Technical Director San Diego State University
24Friction Drive Winch Motorized or manual operation Does not use a Grooved DrumUses a keyed four groove Multi-sheave above and five idler sheaves below Cable is either an endless loop or both ends terminate at wagon
25Drive: 2HP Motor with 25:1 Gear Reducer Motor Output: 1750 RPM Gear Reducer Output: 70RPMTop Cable Speed: ft./sec.Shafts: 13/16” Roller Chain: #50
26Operation of the winch can be changed from motorized to manual by shifting the roller chain from the sprocket on the Gear Reducer to the idler sprocket on the motor mount. By pulling the lower pins on the mount and pivoting the motor mount on the upper bolts, the roller chain can be shifted to the idler.
27A handle for manual operation can be attached to either end of the two shafts on the top of the winch unit.In its current configuration, we have installed a additional 1.5:1 output reduction with the installation of a 20 tooth and 30 tooth sprocket on the two top shafts. This allows some choice of mechanical advantage if the winch is operated manually. This additional reduction decreases the motorized top cable output to 2ft./sec.
28Proper tension on the drive cable is controlled by drawing back the idler sheave assembly on the two threaded rods. This is done by using an impact wrench on the welded nuts on back end of each threaded rod.
29A rotary encoder is attached with #25 roller chain and sprockets to the drive sheave to enable positioning control with our PLC system. This can be interchanged with a mechanical counter if needed for manual operation
30www.surpluscenter.com Friction Drive Winch Major Parts List Baldor #2HP Motor #VM3558Tebay “Buy it now” price $12025:1 Gear Reducer #GF2532BGebay “Buy it now” price $199Grainger #Pillow Blocks (4) #5X685Multi-sheave 11.25”OD #2L371Sheave 7”OD (5) #3X923#50 Roller Chain 10’ #2W09515 Tooth #50 Sprocket (3) Varies with Bore30 Tooth #50 Sprocket # 6G021Friction Drive WinchIndiana Repertory Theatre
31Peter Pan WinchDeveloped and designed by Stephen Henson at California State University Fullertonwith special thanks to Bill Meyer, Matthew McKinney and Scott Shiba for various creative influences during the process of development
32Prototype winch-Form followed function purely-Used with a sprocket instead of three-grooved sheave, for direct chain-drive-Two plates punched to be bolted to the gear box, welded to a cross member punched for hangersVersion 2.0 winch-Rotated motor 90 degrees-Added two vertical angle irons for pushing motor away from batten-Allowing for three-grooved sheave with a double sheave hung above directly from batten (not shown)-Crudely mounted mule blocks for directing cables along batten to scenery-Rotary Limit Switch and Junction box mounted to motor mount plate
34-Top plate is designed to facilitate standard Batten hangers, as well as suspend a swivel double sheave-Slotted flat bars accommodate multiple positions for head blocks as well as twisting into alignment with three-grooved sheave-Center plates are punched accordingly for mounting gear box with encoder and motor suspended from gearbox-Bottom of frame has additional steel structure for mounting rotary limit switch and junction box containing RJ45 connectors.-Head block assembly is punched with extra holes to allow for flexibility with parts
62Good location and labeling for limit and encoder connections
63A list of winch prices for a 1 1/2 HP DC winch 180 v DC 1 1/2 HP motor Grainger 4Z $480.00Gear reducer w/ base Grainger 1L $360.00Dynaper Series R45 Encoder # R $285.00Furnas Rotary limit switch 72:1 54EB23FC $360.00Chain & Sprockets Grainger $125.001 1/4” shafts, pillow blocks, $125.0010” d grooved drum x 11” long Est. $550.006” sheaves for Tension assembly @ $ each3 Groove Sheave w/ hub for Turntable drive$150.00Misc Hardware, bolts, all thread etc $75.00Misc Electrical $48.00Steel for frame $30.00TOTAL $
64Variations on a Theme San Diego State University Stock Winch 5HP AC Vector DriveDrive Mounted on WinchShorter Encoder CablesShorter Limit CablesCreative Conner’s Control SystemMCued Servo System