Turntable Traction Drive Project
This is my design for a Turntable Traction Drive. It's meant to turn a large theatrical turntable covered in sets and actors in a safe reliable way. It can be built for less than $3000 USD.
I was inspired to take on this project by Alan Hendrickson's chain-driven design featured in Technical Designs Solutions for Theatre Volume 2 (Sammler/Harvey 2002). His design shows how a chain drive can rotate a turntable. I was interested in designing an easier-to-integrate "bolt-on" solution.
Feel free to make your own or iterate on this in any way permitted by the license! If you do happen to build one, send me a picture, I'd love to share it!
This project has a website.
Critical Documents
Document Name | Description |
---|---|
Safety and Liability | Discussion of the drive and safety factors associated with its use. |
Design Document | Discussion of design and considerations made. |
Parts Sourcing Guide | Instructions on how to buy the right parts to build your own Turntable Traction Drive. |
Assembly Guide | Instructions on how to build your own Turntable Traction Drive. |
Integration Guide | Instructions for Technical Directors on how to integrate this machine into your set desgin. |
Operation Guide | Instructions for Technical Directors on how to operate this machine. |
Bill Of Materials | A list of the parts required to build this machine. |
Wiring Guide | Instructions for wiring up the VFD, Control Pendant, and Emergency-Stop. |
Custom Parts Overview | A one-page PDF helpful when ordering custom cut steel. |
Creative Commons Attribution 4.0 International | The license under-which these plans are made available. |
Checklists
Document Name | Description |
---|---|
Integration Checklist | A list of integration requirements for safe scenic integration of the Turntable Traction Drive. |
Operations Checklist | A "preshow" checklist to verify before each use of the Turntable Traction Drive. |
Part Files
Part | Description |
---|---|
Chassis Parts | 2D CAD drawings of chassis parts to be cut from 1/4" mild steel. |
Safety Placard | A PDF to be made into a printable label and applied to the top of the chassis. |
Media
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Assembled Chassis Before Welding (photo)
Turntable Traction Drive Specifications
Traction Drive Feature | Detail |
---|---|
Design Units | INCHES |
Height | 9.875" |
Width | 32.875" |
Depth | 33" |
Chassis Weight | ~112 Lbs |
Total Weight | ~228 Lbs |
Number of Parts | 63 |
Minimum Turntable Size | 6' Diameter |
Maximum Turntable Size | Proven on a 23' diameter Turntable with steel and wood scenery. |
Powerplant Details
My motor decision was based on what I had lying around. You may easily sub in your own motor, but for simplicity of integration try to pick a motor matching NEMA Frame 145TC. Otherwise you may have to drill new holes in the Base Plate
and Motor Gusset
.
Powerplant Feature | Detail |
---|---|
Model | General Electric 2HP TEFC (5KE48WN8167) |
Speed | 1725 RPM at 60Hz |
Layout | NEMA Frame 145TC |
Gearhead | Morse 175Q140LR5 |
Gearhead Ratio | 5:1 |
Control Details
In order to vary the speed of drive motor we must use a Variable Frequency Drive (VFD). The VFD will be responsible for managing the speed and acceleration of the traction drive.
VFD for 3 Phase Power (208 VAC)
In our environment we have easy and plentiful access to 3phase 208v. For this reason we have selected a 3phase input VFD. If you have access to 3 phase power you can benfit from our integration notes throughout this documentation.
VFD Feature | Detail |
---|---|
Model | Automation Direct DURA Pulse (GS23-22P0) |
Input Power | 230V 3-Phase (208 is fine) |
Output Power | 1.5 KW (2 HP) |
Output Range | 0 - 600Hz |
Safe Torque Off (STO) | Yes |
VFD for Single Phase (120 VAC)
Our initial testing was performed on a .75 KW 120V VFD. We were able to easily turn the 23' turntable using just a single wall outlet.
VFD Feature | Detail |
---|---|
Model | Hitachi L-100 (L100-007NFU) |
Input Power | 120VAC 15A |
Output Power | 0.75 KW (1 HP) |
Output Range | 0 - 360Hz |
Safe Torque Off (STO) | No |
We decided to replace this VFD for two reasons:
- In our environment 3-phase 208 is easily availble, and since 1HP isn't really up to the demands of our motor, the testing VFD didn't make a lot of sense.
- The intial wiring design of our e-stop buttons was not up to industrial automation standards. Critically, the e-stop was unable to constrain a runaway VFD. As a hedge agasint this risk we have selected a VFD with a Safe Torque Off (STO) feature. This feature adds independant hardware designed to reliably disconnect the output transistors of the VFD from the motor.