Work In Progress: New Polar Scaffold
Posted by mjsouth on February 2, 2008
Now that we have used our new polar scaffold for a couple of weeks, we have reports from the crew that the motor is still running a little slow. So, this is what we’ve done.
| Original Scaffold | Current Motor | New Motor | |
| Gear Box | 60:1 Gear Box | 60:1 Gear Box | 30:1 Gear Box |
| HP | 3/4 HP Motor | 3/4 HP Motor | 1 HP Motor |
| Drive | MD-60 Drive | MD-65 Drive | |
| RPM | |||
| Electricity | 110v Single Phase | 220v Three Phase* | 220v Three Phase* |
* The drive unit is 220v single phase, and puts out 220v three phase. So it should work on any jobsite. 
Just in case you haven’t read the first article, we are switching from the single phase to three phase powered drive system so that we can have adjustable speeds. The longer the scaffold, the longer it takes for one rotation. For instance, spraying consistent concrete at the end of the scaffold might be just the right speed, but spraying towards the middle will be a lot harder with the slower speeds.
The biggest difference is the drive. The original drive that we used had most of the same features that the new one does, except the ability to drive more power to the motor. The new MD-65 has the ability to increase the frequency of the power. So instead of adjusting the power from 40 hertz to 60 hertz, we are able to go from 40Hz to 120 Hz. I use the number 40 Hz for the minimum, because if the motor turned much slower than that, the motor wouldn’t be able to cool itself. I adjusted the drive to 120Hz for the highest setting, because I was concerned that any faster, and we might have to install seat belts on the scaffold.
The only remaining worry is that the increase in speed will decrease the power. Enabling its ability to climb over objects like pipes and rocks in the dome, but I think we have overcome that with the powerful new drive motor. Javier is going to take this scaffold motor with him on Monday, and I will post a report on its progress. Thanks for reading.
Related Links:
