Moving a dome and EM relays

I have a domed observatory. Presently, it has two a/c motors that
operate the rotation of the dome, and the shutter. The latter opens to
the sky as the shutter is raised. I must move either manually with a lever.

I'm about to replace the manual operation with two circuit boards (not
yet purchased)

I have a domed observatory. Presently, it has two a/c motors that
operate the rotation of the dome, and the shutter. The latter opens to
the sky as the shutter is raised. I must move either manually with a lever.

I'm about to replace the manual operation with two circuit boards (not
yet purchased) that will be attached to the dome and the circular
support holding it up, sometimes called a skirt. The dome moves on

wheels. The two boards communicate wirelessly. Solar cells will provide
power to the boards. The electric motors used for manual operation, I
think, will no longer be of use. It looks like they will have to be
replaced by DC batteries. I'm kind of guessing here. However,
according
to the manual for the two boards, relays will be provided. I'm guessing
they will somehow be needed to go between them and each of the circuit
boards.

In article<j9sre8$g35$1_at_dont-email.me>, wolftracks_at_invalid.com says...

I have a domed observatory. Presently, it has two a/c motors that
operate the rotation of the dome, and the shutter. The latter opens to
the sky as the shutter is raised. I must move either manually with a lever.

You seem to be saying you will use
DC batteries to operate the
observatory, rather than AC power
you use now. Am I correct? If that
I believe that's true, but I really do not know yet.
is true, you will need DC motors to
move your dome and shutter, and you
don't mention whether you have DC
motors picked out to replace your
AC ones.
I haven't any idea what DC battery I would need.

I built an observatory controller
recently, and some of what you say
sounds familiar, but some does not
sound right.


Is there a website for the kit you
plan to use, so we could see how it
works?

I'm about to replace the manual operation with two circuit boards (not
yet purchased) that will be attached to the dome and the circular
support holding it up, sometimes called a skirt. The dome moves on

Unless the 'circuit boards' have
motors to control, they're not going
to move anything.

wheels. The two boards communicate wirelessly. Solar cells will provide
power to the boards. The electric motors used for manual operation, I
think, will no longer be of use. It looks like they will have to be
replaced by DC batteries. I'm kind of guessing here. However,
according
to the manual for the two boards, relays will be provided. I'm guessing
they will somehow be needed to go between them and each of the circuit
boards.

Relays turn power on and off, much as
your manual lever does for your AC
motors. Are the relays capable of
switching power for your AC motors?
I have no idea. I do understand the basics of how they work. The ref

I think one of the sensors will sense
when the shutter is fully open or
fully closed, so the control board
can use relays to turn the motor on
and off.

Don't know. See ref.

On 11/15/2011 12:01 AM, aioe wrote:> In article<j9sre8$g3...@dont-email.me>, wolftra...@invalid.com says...

I have a domed observatory.  Presently, it has two a/c motors that
operate the rotation of the dome, and the shutter.  The latter opens to
the sky as the shutter is raised. I must move either manually with a lever.

You seem to be saying you will use
DC batteries to operate the
observatory, rather than AC power
you use now. Am I correct? If that

I believe that's true, but I really do not know yet.> is true, you will need DC motors to
move your dome and shutter, and you
don't mention whether you have DC
motors picked out to replace your
AC ones.

I haven't any idea what DC battery I would need.



I built an observatory controller
recently, and some of what you say
sounds familiar, but some does not
sound right.

Is there a website for the kit you
plan to use, so we could see how it
works?

I'm not sure it will be helpful, but here
http://www.cyanogen.com/help/maxdome/MaxDome.htm>. There's a 66 page or
so pdf for it somewhere on their site that is just a copy of the other
sources on that page.  They get more specific than the Intro.







I'm about to replace the manual operation with two circuit boards (not
yet purchased) that will be attached to the dome and the circular
support holding it up, sometimes called a skirt. The dome moves on

Unless the 'circuit boards' have
motors to control, they're not going
to move anything.

wheels. The two boards communicate wirelessly. Solar cells will provide
power to the boards. The electric motors used for manual operation, I
think, will no longer be of use. It looks like they will have to be
replaced by DC batteries.  I'm kind of guessing here. However,
according
to the manual for the two boards, relays will be provided. I'm guessing
they will somehow be needed to go between them and each of the circuit
boards.

Relays turn power on and off, much as
your manual lever does for your AC
motors. Are the relays capable of
switching power for your AC motors?

I have no idea. I do understand the basics of how they work. The ref
above will likely tell.

I think one of the sensors will sense
when the shutter is fully open or
fully closed, so the control board
can use relays to turn the motor on
and off.

Don't know. See ref.- Hide quoted text -

- Show quoted text -

If you've got AC power why do you want to switch to DC?
You can get AC relays too.

You seem to be saying you will use
DC batteries to operate the
observatory, rather than AC power
you use now. Am I correct? If that

I believe that's true, but I really do not know yet.

In article<706133c1-93cf-4dbb-a01a-d47c9e84c23a@
14g2000yqo.googlegroups.com>, gherold_at_teachspin.com says...


If you've got AC power why do you want to switch to DC?
You can get AC relays too.

This may not apply in the OP's case, but
some pretty elaborate 'scopes get hauled
out to a field for a 'star party'. They
get run off of car batteries in series.

That was part of the spec for the one I
built.
Believe me this scope is going nowhere. It's big.

On 11/15/2011 10:23 PM, Randy Day wrote:
In article<706133c1-93cf-4dbb-a01a-d47c9e84c23a@
14g2000yqo.googlegroups.com>, gherold_at_teachspin.com says...


If you've got AC power why do you want to switch to DC?
You can get AC relays too.

This may not apply in the OP's case, but
some pretty elaborate 'scopes get hauled
out to a field for a 'star party'. They
get run off of car batteries in series.

That was part of the spec for the one I
built.
Believe me this scope is going nowhere. It's big.

This may not apply in the OP's case, but
some pretty elaborate 'scopes get hauled
out to a field for a 'star party'. They
get run off of car batteries in series.

That was part of the spec for the one I
built.
Believe me this scope is going nowhere. It's big.

I have a domed observatory. Presently, it has two a/c motors that
operate the rotation of the dome, and the shutter. The latter opens to
the sky as the shutter is raised. I must move either manually with a lever.

I'm about to replace the manual operation with two circuit boards (not
yet purchased) that will be attached to the dome and the circular
support holding it up, sometimes called a skirt. The dome moves on
wheels. The two boards communicate wirelessly. Solar cells will provide
power to the boards. The electric motors used for manual operation, I
think, will no longer be of use.

It looks like they will have to be
replaced by DC batteries. I'm kind of guessing here. However, according
to the manual for the two boards, relays will be provided. I'm guessing
they will somehow be needed to go between them and each of the circuit
boards.

Does this latter part make any sense? Comments welcome. I'm just trying
to get a feel for what I may need beyond the two circuit boards, and a
few minor accessories provided with it. No batteries included!

The following materials are included in the kit (rotation and shutter
control version):
•
Two controller boards
•
One motor sensor board
•
One motor sensor cable
•
One magnetic sensor with magnet
•
One serial (RS-232) cable assembly
•
Mounting hardware for optical sensor
•
Computer CD-ROM
•
Induction wire
•
Mounting hardware for induction wire

W. eWatson used his keyboard to write :
On 11/15/2011 10:23 PM, Randy Day wrote:
In article<706133c1-93cf-4dbb-a01a-d47c9e84c23a@
14g2000yqo.googlegroups.com>, gherold_at_teachspin.com says...


If you've got AC power why do you want to switch to DC?
You can get AC relays too.

This may not apply in the OP's case, but
some pretty elaborate 'scopes get hauled
out to a field for a 'star party'. They
get run off of car batteries in series.

That was part of the spec for the one I
built.
Believe me this scope is going nowhere. It's big.

If you could give us a picture and tell us how big the AC motors are
would help.
This sounds like a bigger job than you imagine.
Changeing the motors will take a significant amount of mechanical
engineering.

I'm back after a trip. Azimuth AC motor is (see Grainger) Dayton 1LPN9,

In article<ja0pnf$a4l$1_at_dont-email.me>, wolftracks_at_invalid.com says...

[snip]

This may not apply in the OP's case, but
some pretty elaborate 'scopes get hauled
out to a field for a 'star party'. They
get run off of car batteries in series.

That was part of the spec for the one I
built.
Believe me this scope is going nowhere. It's big.

Then I'd venture to say you're better
off using relays to switch the AC to
your existing motors. That way you
don't have to re-engineer a setup
that already works. Buy 12v relays
with switch contacts rated to handle
your motors; you can hook the coils
up to the motor outputs of your
controller.

You can still use solar to operate
the controllers if you like, too...

You can get a feel for the size of matters by going to my web site at

In article<j9u79v$713$1_at_dont-email.me>, wolftracks_at_invalid.com says...

[snip]

You seem to be saying you will use
DC batteries to operate the
observatory, rather than AC power
you use now. Am I correct? If that

I believe that's true, but I really do not know yet.

Before you decide to buy that control
package, you need to decide:

- what kinds of DC motors can replace
your AC motors, in terms of physical
size (will they fit?), torque (can
they move the dome and shutter?) and
speed (can they move them fast enough?)

Your website specifies that it runs 12v
motors up to 5 amps. 12v car batteries
or marine batteries should do fine. It
also says you can use external relays to
control AC motors. That might be the
simplest way for you.

If you still want DC, you might find
some power window motors at an auto
scrapyard, or even a car starter motor,
though that might be overkill...

Doubtful. The dome weighs 1500 pounds and the shutter about 400 pounds.

W. eWatson wrote:
I have a domed observatory. Presently, it has two a/c motors that
operate the rotation of the dome, and the shutter. The latter opens to
the sky as the shutter is raised. I must move either manually with a
lever.

Assuming that the existing a/c motors move the dome & shutter with
whatever degree of accuracy/speed/precision you need, there is no need
to change them. Literature for the new controller says:
"It is possible to connect other types of motors, such as AC motors,
using external relays."
Good find. I guess you found that in the pdf manual. Yes, I see it.

Assuming that the lever you use now operates a switch, you will
replace that switch with relay contacts. In fact, you may be able
to retain the lever setup as is, and just wire the relay contacts
in parallel with the existing switch. Retaining the lever setup
will allow you to manually operate just as you do now, if you
need to.
I understand the concept of a relay, but how does it work in the case of

If you do operate the dome manually with the new controller
powered off or not functioning, you need a means of letting the
controller "know" the position of things. Since it didn't control
the movement and couldn't "see" the movement, it won't know the
position. You would have to tell the PC where the thing is currently
aimed so that it can move the proper distance & direction to the new
aiming point.
Pages 12-15 of the manual talk about optical rotation sensor. I think

I'm about to replace the manual operation with two circuit boards (not
yet purchased) that will be attached to the dome and the circular
support holding it up, sometimes called a skirt. The dome moves on
wheels. The two boards communicate wirelessly. Solar cells will
provide power to the boards. The electric motors used for manual
operation, I think, will no longer be of use.

They will work as well as they do now if you use the external relays
with the new controller.
"new controller"? A circuit card.

It looks like they will have to be replaced by DC batteries. I'm kind
of guessing here. However, according to the manual for the two boards,
relays will be provided. I'm guessing they will somehow be needed to
go between them and each of the circuit boards.

Does this latter part make any sense? Comments welcome. I'm just
trying to get a feel for what I may need beyond the two circuit
boards, and a few minor accessories provided with it. No batteries
included!

You need a battery, and the external relays. According to the list
you posted below, the relays are not included.
If I go DC, then I'll need two 12v batteries, and two solar cells.

It might be a good idea to discuss the installation with someone who
has already done it. To me, it looks like setting up their optical
rotation sensor may be a somewhat finicky operation.
Despite the popularity of the dome, I have found no one on the MaxDomeII

purchase the thing unless I first determined that I could install
the sensor properly. The heart of their equipment depends entirely
on the sensor. It counts every revolution of the motor, and it
relies on the sensor to detect that revolution. You have to paint
the motor shaft 1/2 white and 1/2 black, and mount the sensor a
specific distance from the shaft at a specific height above the
mounting plate. For the system to work properly, *every* complete
revolution of the motor shaft has to be detected. Miss one, and your
aim will be off by the amount of movement each complete motor
revolution produces. Also, there can't be any accumulation of
error or you'll continually have to recalibrate.
Something that may save me on this whole matter is a friend who lives 45

Ed


The following materials are included in the kit (rotation and shutter
control version):
•
Two controller boards
•
One motor sensor board
•
One motor sensor cable
•
One magnetic sensor with magnet
•
One serial (RS-232) cable assembly
•
Mounting hardware for optical sensor
•
Computer CD-ROM
•
Induction wire
•
Mounting hardware for induction wire