Dear All,
To begin, I apologise for any really stupid comments below. I've tried to watch a variety of videos covering shaft alignment, and read several articles/guides, but my measurements continue to confuse me (quite probably because I'm doing it wrong!)
I have a vertical shaft passing through in the simplest terms two pairs of ball bearings, one at the bottom (which is fixed) and one at the top, which I can translate horizontally using what I believe are termed leveling screws.
At the top of the shaft, a toothed pulley is placed, which lies between two other toothed pulleys, one of which is below a servo-motor, coupled with a flexible coupling. The other can be moved horizontally to loosen or tighten the belt, and there are additional tightening pulleys (without teeth) for the outsides of the belt which allow some additional tensioning after the toothed pulley is fixed.
Above the shaft pulley, there is a fixed coupling to a split ring. This is basically just a piece of brass pipe with some setscrews on the sides at the top and bottom to affix to the shaft and to the split ring rotor.
Given the fixed coupling, I'm trying to adjust the shaft angle/position (at the top) using the leveling screws, and the co-axiality(?) of the coupling to the shaft using pieces of aluminium tape as shims, such that the rotor of the split ring isn't experiencing large movement in the horizontal plane (excluding of course the rotation).
I'm currently using a dial indicator mounted to the frame with the dial against the coupling or alternatively the shaft (when I remove the pulley to allow some minimal access and turn by hand). My understanding is that readings at 9 and 3 on a clock should sum to the same value as 12 and 6, which is not what I observe. I gather this means I'm probably doing something wrong, but I can't see what it is.
My readings are moderately repeatable - for example when measuring on the shaft directly (not the coupling) I get going in one direction 4, 3.5, 1, -3 and then 5 at the starting position, followed by (the same) 5, 5, 1, -5 and 3 back at the starting position. One increment is I believe 0.01mm. The second set is fairly similar to the first, but the sums of opposite points is not even remotely similar. When measuring the coupling a similar pattern is visible, but magnified by a factor of about 4. This might be due to measuring further from the ball bearing which constrains the top of the axis?
How can I proceed to try and reduce the noise produced by the slip ring thudding back and forth as the shaft rotates? I can't visualize what is wrong to allow these measurements to be made. The shaft runs at speeds between 0 and around 2000rpm, in either direction.
To begin, I apologise for any really stupid comments below. I've tried to watch a variety of videos covering shaft alignment, and read several articles/guides, but my measurements continue to confuse me (quite probably because I'm doing it wrong!)
I have a vertical shaft passing through in the simplest terms two pairs of ball bearings, one at the bottom (which is fixed) and one at the top, which I can translate horizontally using what I believe are termed leveling screws.
At the top of the shaft, a toothed pulley is placed, which lies between two other toothed pulleys, one of which is below a servo-motor, coupled with a flexible coupling. The other can be moved horizontally to loosen or tighten the belt, and there are additional tightening pulleys (without teeth) for the outsides of the belt which allow some additional tensioning after the toothed pulley is fixed.
Above the shaft pulley, there is a fixed coupling to a split ring. This is basically just a piece of brass pipe with some setscrews on the sides at the top and bottom to affix to the shaft and to the split ring rotor.
Given the fixed coupling, I'm trying to adjust the shaft angle/position (at the top) using the leveling screws, and the co-axiality(?) of the coupling to the shaft using pieces of aluminium tape as shims, such that the rotor of the split ring isn't experiencing large movement in the horizontal plane (excluding of course the rotation).
I'm currently using a dial indicator mounted to the frame with the dial against the coupling or alternatively the shaft (when I remove the pulley to allow some minimal access and turn by hand). My understanding is that readings at 9 and 3 on a clock should sum to the same value as 12 and 6, which is not what I observe. I gather this means I'm probably doing something wrong, but I can't see what it is.
My readings are moderately repeatable - for example when measuring on the shaft directly (not the coupling) I get going in one direction 4, 3.5, 1, -3 and then 5 at the starting position, followed by (the same) 5, 5, 1, -5 and 3 back at the starting position. One increment is I believe 0.01mm. The second set is fairly similar to the first, but the sums of opposite points is not even remotely similar. When measuring the coupling a similar pattern is visible, but magnified by a factor of about 4. This might be due to measuring further from the ball bearing which constrains the top of the axis?
How can I proceed to try and reduce the noise produced by the slip ring thudding back and forth as the shaft rotates? I can't visualize what is wrong to allow these measurements to be made. The shaft runs at speeds between 0 and around 2000rpm, in either direction.