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operation:technical

12 m Telescopes

Gearboxes

The planetary type gearboxes are manufactured by Eskridge in Olathe, Kansas.

Elevation
Azimuth

The upper gearbox has proved troublesome, getting water in the top, where there is no seal. The water sinks to the bottom of the box and wrecks the seal on the output shaft and damages the bearing above the seal. Oil and water then go from the upper box into the lower main box. The main box becomes overfilled with oil. The upper gearbox runs dry and the main ball bearing on the output shaft becomes noisy. The planetary gear assembly has small rollers inside the planet gears which may also require attention. The upper gearbox may be removed with the main body and pinion gear remaining in place. Upper single stage planetary gearbox manual

There is an oil drain plug on the lower main gearbox body which is 3/8“ square and is about 1/4” above the bottom of the case, so not all the oil will drain out. There is also a smaller drain plug on the bottom of the output shaft case near the bottom bearing which is 1/4“ Allen hex. This is only accessible once the gearbox is disengaged from the ring gear and lifted up above the mounting plane. Lower double planetary gearbox manual

The pinion gear on the main output shaft will require heat and a puller to remove. The lower shaft has to be pressed from its upper bearing, heat needs to be applied to the upper bearing. The lower bearing can be pulled with a large gear puller from the lower shaft. The seal is wrecked in the process and needs replacement, reassemble with oil on the shaft and grease between the lips of the oil seal. If the seal on the upper planetary gear assembly has failed it has probably run dry. It may have had water enter in the top input shaft opening. It will need dismantling, cleaning and the roller bearings replaced as a set if there are signs of wear. The planetary gear unit is dismantled by driving the roll pin visible from the outside of the carrier inwards into the planetary gear shaft with a 3/16 inch punch. The shaft will then press out of the carrier and the roll pin can then be driven from the shaft. The roll pin is driven flush with the carrier body upon reassembly.

Webcams

The webcams are useful as a visual check that the antennas are out of park, moving and slewing, when live pages, or remote interfaces fail. There is a wireless webcam at each Auscope site; the username and password are the usual for observers, http://webcamho.phys.utas.edu.au http://webcamhb.phys.utas.edu.au http://webcamke.phys.utas.edu.au http://webcamyg.phys.utas.edu.au

26 m Telescope

Receiver Position

In Otter interface [r] resets box in focus cabin. If receiver position display is “zero” indicates error (all bits zero) indicative of reset required. Above fault also means auto receiver position not working.

Cryo System

Action plan after warmed and severe pressure drop. Compressor has cut out as pressure went below 150 psi

- commence vaccuming S/X using turbo pump

- turn off the SX cryodyne in the diesel room so that the blue motor stops

- turn off the L-band cryodyne by pulling out the lead to the L-band cold head in the focus cabin

- use hastings vac gauge and Edwards oil filled vac pump to pump L-band dewar while it warms(dear valve open whilst pumping).

- top up the helium supply to 300 psi if the compressor is running OK. If has shut down, increase the pressure slightly then restart the compressor and increase the pressure to 300 psi supply.

- locate the leak. Leak detector goes yellow for heavy molecules, red for light gas. Keep skin away from tip, and don't breathe near tip.

- power down the compressor

- replace leaking hose

- power up the compressor, must have > 150 psi to start

-top helium up to 300 psi once compressor running

- commence s/x cooling by turning on cryo S/X power in diesel room

- start L-band cryodyne

- 3 hours of cooling with vac pump on L-band is required

- close l-band dewar valve

- remove Edwards pump.

-close SX dewar valve and turn off turbo

/home/www/auscope/opswiki/data/pages/operation/technical.txt · Last modified: 2018/01/28 22:02 by Warren Hankey