Track Inspection 970402 + 970418 update

Each welded joint was closely inspected for signs of damage to weld or adjacent grout. All joints were inspected for signs of steps, damage etc at the joint surface. An 'OK' result indicates that the joint was basically sound as far as could be determined.

Joint	Inner	Outer	Welded	Notes
-------------------------------------
1/2	OK	OK	Yes	welded 17.Apr.97

2/3	OK	OK	Yes	Welded Aug.96
				Powder near joint (lots)

3/4	*	OK	Yes	Welded Aug.96
				Powder near joint, 
				* Burr on track edge. otherwise OK

4/5	OK	OK	Yes	Welded Oct.95
				Powder near joint

5/6	OK	OK	Yes	Welded Aug.96
				Powder near joint

6/7	OK	OK	No	Grouted (only) Aug.96
				Not prepped 
				Powder near joint (lots)

7/8	OK	OK	No	Welded 10.Apr.97
				Powder near joint

8/9	OK	OK	No	Not prepped
				Powder near joint

9/10	OK	OK	Yes	Welded Aug.96
				Powder near joint

10/11	OK	OK	Yes	Welded Aug.96
				Powder near joint

11/12	OK	OK	No	Not prepped
				Powder near joint

12/13	OK	OK	Yes	Welded Aug.96
				Powder near joint

13/14	OK	OK	Yes	Welded Aug.96
				Powder near joint

14/1	OK	OK	Yes	Welded Aug.96
				Powder near joint

In Summary all the joints and new grout looked fine.

Notes on 'Powder'

The 'powder' refers to black stuff that seems to collect at joints. It has never been well classified, candidates would be :

1. From scrapers or associated brush seal or scraped off track oxide
2. From wear of the joint edges
3. Motor/electrical stuff?

Notes on Wheels

Wheel 1 : no findings
Wheel 2: Blower located adjacent to leg, may duct cold or hot cabin air close to the leg. Scraper very noisy. Scraper behaviour will vary CV-CCW. Higher motor torque would affect all motors due to servo system
Wheel 3 inner motor cover ccw-most edge was much lower than other covers: approx 0.75-2mm. May be a cause of foul on 3/4? However, when I checked by rotating slowly past the joint did not appear to come close to touching
Wheel 4: adjacent to steps, otherwise no findings

Inclinometry Notes

The only potential culprit for the inclinometry weirdness I can see here is to postulate that either a foul (or debris) at the Wheel 3 position occured, or that the badly adjusted scraper is causing torque increases (and hence structural wind up) at certain points. The scraper friction may be temperature/humidity dependent.
The recent motor cubicle/drive amp problems are more likely to be a cause.
In any event we will adjust the scraper as part of az-track work in April. Longer term we might consider PTFE scrapers?

 ========================================================================
 |      Ian Pain                                                        |
 |									|
 | 	Mechanical Engineer, Joint Astronomy Centre			|
 |									|
 |	660 N.A'ohoku Place, University Park, Hilo, Hawaii 96720. USA	|
 |									|
 |	Tel: 	US-(808)-969-6540	Fax: 	US-(808)-961-6516	|
 |	Email:	pain@jach.hawaii.edu	http:	www.jach.hawaii.edu	|
 |									|
 ========================================================================