Strostkovy
Titanium
- Joined
- Oct 29, 2017
About a year and a half ago I built a sand blasting booth on a budget out of two shipping containers. I has three 36" fans that spin at 500 rpm and do a great job. They are rated to 750 rpm at 1.5hp each.
Unfortunately, they are failing for a variety of reason. One motor arrived damaged and we never fixed it so we've only had two fans running. The v belts have been constant issues with fast wear, and the set screw pulleys do not stay secured to the shaft. We've been running one fan due to a seized flange bearing, and a bearing on the last remaining fan is sounding bad.
It's about that time to fix this up. I want to replace the cheap single phase TEFC motors with three phase motors on a VFD. The speed control will be lovely as we can slow them down for using the small blaster or during heavy rain or speed them up when blasting something that produces a lot of dust, or if we add hardware cloth to the grill if dust outside becomes an issue. As of now we use aluminum oxide and the dust going outside presents us no problems, and does not linger in the air long before it falls. The acceleration limit of a VFD will also help belt wear, as frequent starts and stops on the very heavy fans will not allow the belts to slip in sandy conditions nearly as much.
The cooling space is not ideal for the motors, as I thought the motors were shorter when I ordered them. I'm going to oversize the new motors a bit for the environment and VFD. At 750 RPM the 1.5HP cheap single phase motors were overheating. I'm going to use a 2hp motor with a pulley reduction to get it down to 650 rpm max.
Set screws will be replaced with taper bushings. I've learned from other repairs I've had to make on some ovens and spray booths that set screws just aren't great, even with a snug fit and keyway.
As far as the pulley and belt wear goes, I think a large issue is due to sand in the groove while the belt slips, causing a lot of wear. I also feel like 1.5hp is pushing it for 1/2" belt with such a small drive pulley and long drive distance. I'm considering using a timing belt to eliminate that slip, and also a much wider belt. Otherwise I can use a serpentine style belt.
Anybody have any input on fixing this up?
Unfortunately, they are failing for a variety of reason. One motor arrived damaged and we never fixed it so we've only had two fans running. The v belts have been constant issues with fast wear, and the set screw pulleys do not stay secured to the shaft. We've been running one fan due to a seized flange bearing, and a bearing on the last remaining fan is sounding bad.
It's about that time to fix this up. I want to replace the cheap single phase TEFC motors with three phase motors on a VFD. The speed control will be lovely as we can slow them down for using the small blaster or during heavy rain or speed them up when blasting something that produces a lot of dust, or if we add hardware cloth to the grill if dust outside becomes an issue. As of now we use aluminum oxide and the dust going outside presents us no problems, and does not linger in the air long before it falls. The acceleration limit of a VFD will also help belt wear, as frequent starts and stops on the very heavy fans will not allow the belts to slip in sandy conditions nearly as much.
The cooling space is not ideal for the motors, as I thought the motors were shorter when I ordered them. I'm going to oversize the new motors a bit for the environment and VFD. At 750 RPM the 1.5HP cheap single phase motors were overheating. I'm going to use a 2hp motor with a pulley reduction to get it down to 650 rpm max.
Set screws will be replaced with taper bushings. I've learned from other repairs I've had to make on some ovens and spray booths that set screws just aren't great, even with a snug fit and keyway.
As far as the pulley and belt wear goes, I think a large issue is due to sand in the groove while the belt slips, causing a lot of wear. I also feel like 1.5hp is pushing it for 1/2" belt with such a small drive pulley and long drive distance. I'm considering using a timing belt to eliminate that slip, and also a much wider belt. Otherwise I can use a serpentine style belt.
Anybody have any input on fixing this up?
