Re: [ap-gto] Re: 1200 DEC tight


Jun 5, 2001

 


----------------------------

#2639 Jun 5, 2001

I've got this same situation on the DEC side. When balancing my

scope the RA axis is extremely smooth running and responds to minute

changes in the position of the counterweights. On the other hand,

the DEC axis is a real chore to move and does not move freely during

balance, but requires some force to get it to budge. Because of that

I'm never sure how close to balance I actually am getting. I have

repositioned these plastic DEC clutches but it doesn't seem to make a

difference. I can understand that perhaps more drag is desirable on

the DEC axis than the RA axis, since it would prevent the OTA from

swinging wildly when the 4 clutch knobs are released for balancing.

Any suggestions? My concern is that the DEC motor might be running

under more of a load than it should be. Thanks.



Dave Jurasevich

--- In ap-gto@y..., chris1011@a... wrote:

> In a message dated 6/5/2001 1:55:16 PM Pacific Daylight Time,

carlb@m...

> writes:

>

>

> > My 1200 mount is now getting very hard to turn by hand in RA. I

first

> > noticed

> > it when I tried to rebalance the OTA. In it's current state it

is

> > impossible to

> > balance.

>

> It sounds like the plastic clutch plugs are splayed at the ends.

Call our

> number at 815-282-1513 during the day and talk to Wally. He can

tell you how

> to check for this and send you some new ones to install.

>

> Roland Christen

>

>

> [Non-text portions of this message have been removed]



----------------------------

#2640 Jun 5, 2001

In a message dated 6/5/2001 2:53:27 PM Pacific Daylight Time,

howldog@... writes:



> . I have

> repositioned these plastic DEC clutches but it doesn't seem to make a

> difference. I can understand that perhaps more drag is desirable on

> the DEC axis than the RA axis, since it would prevent the OTA from

> swinging wildly when the 4 clutch knobs are released for balancing.

> Any suggestions? My concern is that the DEC motor might be running

> under more of a load than it should be. Thanks.

>

>

The amount of clutching has nothing to do with the load on the motor. Even if

the axes were welded on, the motor load would be the same. The clutches do

not lock the shafts down to the housing, they merely couple the axis to the

drive gear, like in a car.







[Non-text portions of this message have been removed]



----------------------------

#2641 Jun 5, 2001

OK, let me start all over again using the proper nomenclature. I am

referring to the DEC damper knobs, not the clutch knobs. I am aware

that the clutch knobs lock the shaft to the housing. My mistake in

improperly identifying the wrong "knob". Now back to the damper

knobs; Is it correct that these damper knobs adjust the resistance

felt when pushing an unclutched axis by hand? That is what I read on

page 11 of the GTO Servo Motor Drive manual. I assumed that

adjusting these damper knobs a bit might just loosen my DEC axis up

somewhat and make it easier to move it in an unclutched state. What

I have found is that the damper knobs have no affect on my DEC axis

stiffness. This is the issue I'm trying to address; What might be the

reason for the tightness of the unclutched DEC axis? Any help would

be appreciated.



Regards,



Dave Jurasevich

--- In ap-gto@y..., chris1011@a... wrote:

> In a message dated 6/5/2001 2:53:27 PM Pacific Daylight Time,

> howldog@f... writes:

>

>

> > . I have

> > repositioned these plastic DEC clutches but it doesn't seem to

make a

> > difference. I can understand that perhaps more drag is desirable

on

> > the DEC axis than the RA axis, since it would prevent the OTA

from

> > swinging wildly when the 4 clutch knobs are released for

balancing.

> > Any suggestions? My concern is that the DEC motor might be

running

> > under more of a load than it should be. Thanks.

> >

> >

> The amount of clutching has nothing to do with the load on the

motor. Even if

> the axes were welded on, the motor load would be the same. The

clutches do

> not lock the shafts down to the housing, they merely couple the

axis to the

> drive gear, like in a car.

>

>

>

> [Non-text portions of this message have been removed]



----------------------------

#2647 Jun 6, 2001

In a message dated 6/5/2001 6:22:31 PM Pacific Daylight Time,

howldog@... writes:



> . I assumed that

> adjusting these damper knobs a bit might just loosen my DEC axis up

> somewhat and make it easier to move it in an unclutched state. What

> I have found is that the damper knobs have no affect on my DEC axis

> stiffness. This is the issue I'm trying to address; What might be the

> reason for the tightness of the unclutched DEC axis? Any help would

> be appreciated.

>

>



The damper knobs simply provide damping to prevent axis motion in windy

conditions. They have no effect on axis stiffness. It is the clutch plugs

that need to be replaced. The clutch knobs push down on 4 delrin plugs which

provide the coupling to the gear. Obviously, if these plugs have somehow been

squashed too tightly in the hole, they will not release when the clutch knobs

are turned counterclockwise. They must be pulled out and new ones put in

place. Call Wally and he will advise you the best way to proceed.



Roland Christen





[Non-text portions of this message have been removed]







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