We performed the coil alignment test yesterday afternoon.

First we had difficulty getting the laser tracker to become stable. it was during approximately 0.005 in. It appears that the portable transformer power supply that was being used induced some noise into the system. Once we plugged into house power the noise reduced to approximately 0.0005in.

Then we installed 1/2in. thick pieces of G-10 at three locations. C-1 coil was on the bottom and C-3 was on the top. When we loaded the C-3 coil onto the C-1 coil we noticed that the C-1 deflected 0.068in. downward and to the right. This was in the direction of the 20° taper of the base. Then we unloaded the coil and noticed that it came back to a reading of 0.025in. We then reloaded the coil and founded that it returned to the 0.068in. position. We then at the end of the test we measured the bottom of the planned of the fixture of the 20° fixture and learned that the back end of the fixture (thicker) flexed about 0.040in. on the floor and up the front edge of the fixture deflected about 0.013in. on the floor. In other words the NCSX floor has a significant amount of spring in the floor substrate.

The procedure we used was once we've identified as we decided that we must take our readings at the fully loaded position. So employing a scale in the load line we ensured that the coil was fully loaded for our measurements. Four plates were use one each leg, in order to provide lateral and rotational translation of the C-3 coil on top.

once we understood that the problems within the system, we also learned that there were hard interferences between C-1 and C-3 coil which provided very little wiggle room for us to perform the test without interference. One of the clamps number 71 on the C-1 coil comes in extremely close proximity to the corresponding clamp on the C-3 coil. Additionally, the wing by the key comes in contact with the G-10 and steel spacer poloidal break. Therefore in ordered to perform a test, we physically offset the coil slightly in order to provide about a sixteenth of an inch wiggle room between the two coils so that the test could be performed uninhibited.

Lowered the upper C-3 coil fully on the G-10 blocks located in three places around coil. Metrology measurements were taken which located both the bottom coil and also the top coil. As shown in the attached picture. Then the top coil was lifted off allowed to float and the G-10 pieces were replaced with two 1/4in. G-10 pieces and nominal piece of shim gages.

The coil was fully loaded and z direction numbers taken. we were about +/- 0.030 - 0.050" off

We lifted the coil and adjusted the metal shim pack.

Lowered the coil and took another set of measurements, We were within a few thousands.

Repeated the process and arrived at Z less than 0.001" within 25 minutes.

Then we looked at the X-Y and rotational measurements. We were off about 0.180"

We adjusted the screws by eye and got down to about 0.075 noted that the z position remained unchanged.

Repeated the process a few times and got down to with in 0.020" noted that the z position changed about 0.030" due to a shift of the bottom coil on the wedge since it was only bolted in two places.

Stopped there since we were dealing with the sponginess of the floor and the poor bolting of the coil to wedge.

We also decided that a set of dial indicators would greatly assist the positioning.

The test was unanimously deemed a success.