AZ-EQ6 / Atlas AZ : list of periodic terms of each elements

[Fred_76]

Hello

Here is a list of the main periods associated to the AZ-EQ6 mount elements. You will also find the reference and quantities of each ball and needle bearing should you need replacement :

- belt (71 teeth, T2.5) : 11’48’’ (2nd harmonic : 05’54’’)

- worm gear and its pulley (48 Teeth, 2.5 mm pitch) : 07’59’’ (2nd harmonic : 03’59’’)

- stepper motor's pulley (12 teeth, 2.5 mm pitch) : 02’00’’ (2nd harmonic : 01’00’’)

- tooth period : 00’10’’ (2nd harmonic : 00’05’’)

Period of return of the same alignment between belt and pulleys : 09h26’27’’

Worm gear axis ball bearings (ref. 608 ZZ or 608 2RS, qty : 2/worm gear)

- inner track defect : 01’48’’

- outer track defect : 03’07’’

Stepper motor internal ball bearings (ref. 625 ZZ, qty : 2/motor)

- inner track defect : 00’24’’

- outer track defect : 00’39’’

The other mount's RA and DEC axis needle bearings periods are too long to be noticed :

Needle bearings (ref. NK 40/20 NT, qty : 2/axis)

- inner track defect : 01h23’54’’

- outer track defect : 01h36’29’’

- needle defect : 01h40’41’’

Needle thrust bearing (ref. AXK 6590, qty : 2/axis)

- tracks defect : 55’15’’

- needle defect : 54’35’’

I hope these periods will be added to PecPREP...

Note that PEC should give better results if one replaces the 71 teeth belt by a 72 teeth belt. It does not change the reduction factor of the mount. When using a 71 teeth belt, the belt shall turn 48 times (and the worm gear pulley 71, and the motor pulley 284) so that the three elements are back to the same configuration : it needs about 9h30. But when using a 72 teeth belt, only 2 turns are needed : the worm pulley will turn 3 times and the motor pulley 12. Only 24 minutes... far better than 9h30 ! However, T2.5 Lg:180 mm 72 teeth h:6 mm belts are a bit harder to source.

Fred