Soft Start Module, Inverter and Motor--Observatory Dome

[W. eWatson]

Back to my dome. I had a six week trip outage and am coming up to speed
by reviewing matters.

For the shutter motor, he idea is to not be dependent upon AC for it,
since the AC motor has a power cord to the area below the dome, the
skirt, and attaches to the skirt where the AC power is. The cord can get
tangled on the telescope. Don't want that to happen. The cord must go.

A fellow quite far from me who knows this stuff well suggested that to
power the shutter movement. He's not always available.

He says I might need something called a soft start module to avert a
high power need when the dome first starts to move. I think that's the
purpose.

The idea is to put a 12v deep cycle in the dome area like:

12v dc deep cycle battery->inverter->present AC motor. I'm guessing the
soft start device belongs between the battery and inverter. I found this
on the Grainger site:
<http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=motor+soft+start+module&op=search&Ntt=motor+soft+start+module&N=0&GlobalSearch=true&sst=subset>

I got there by searching for soft start module. The inverter is a
Tripp-lite 1250W unit. The tech I talked to at Grainger didn't know much
about these devices. Where does it go in the line, and how does it get
connected to the devices on either side of it?

Bonus question.
For the rotation of the dome, I can still use the AC motor. (BTW a
circuit board goes on the dome and skirt, and the one on the skirt
connects to a PC by a RS-232 connection. The PC software controls both
motors.) There's a hand switch on the edge of the skirt that one pushes
either left or right to make the dome rotate. It needs to be replaced a
power relay. I think this might do the trick
<http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=2DR99&op=search&Ntt=2DR99&N=0&GlobalSearch=true&sst=subset>.
Presently 8 lines go out of the switch to the motor. 5 to the motor, and
3 to a shutter limit switch.

Comments?

 

[Jamie]

W. eWatson wrote:

Back to my dome. I had a six week trip outage and am coming up to speed
by reviewing matters.

For the shutter motor, he idea is to not be dependent upon AC for it,
since the AC motor has a power cord to the area below the dome, the
skirt, and attaches to the skirt where the AC power is. The cord can get
tangled on the telescope. Don't want that to happen. The cord must go.

A fellow quite far from me who knows this stuff well suggested that to
power the shutter movement. He's not always available.

He says I might need something called a soft start module to avert a
high power need when the dome first starts to move. I think that's the
purpose.

The idea is to put a 12v deep cycle in the dome area like:

12v dc deep cycle battery->inverter->present AC motor. I'm guessing the
soft start device belongs between the battery and inverter. I found this
on the Grainger site:
http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=motor+soft+start+module&op=search&Ntt=motor+soft+start+module&N=0&GlobalSearch=true&sst=subset


I got there by searching for soft start module. The inverter is a
Tripp-lite 1250W unit. The tech I talked to at Grainger didn't know much
about these devices. Where does it go in the line, and how does it get
connected to the devices on either side of it?

Bonus question.
For the rotation of the dome, I can still use the AC motor. (BTW a
circuit board goes on the dome and skirt, and the one on the skirt
connects to a PC by a RS-232 connection. The PC software controls both
motors.) There's a hand switch on the edge of the skirt that one pushes
either left or right to make the dome rotate. It needs to be replaced a
power relay. I think this might do the trick
http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=2DR99&op=search&Ntt=2DR99&N=0&GlobalSearch=true&sst=subset>.
Presently 8 lines go out of the switch to the motor. 5 to the motor, and
3 to a shutter limit switch.

Comments?

Slip rings.

Jamie

 

[W. eWatson]

On 4/11/2012 2:37 PM, Jamie wrote:

W. eWatson wrote:
Back to my dome. I had a six week trip outage and am coming up to
speed by reviewing matters.

For the shutter motor, he idea is to not be dependent upon AC for it,
since the AC motor has a power cord to the area below the dome, the
skirt, and attaches to the skirt where the AC power is. The cord can
get tangled on the telescope. Don't want that to happen. The cord must
go.

A fellow quite far from me who knows this stuff well suggested that to
power the shutter movement. He's not always available.

He says I might need something called a soft start module to avert a
high power need when the dome first starts to move. I think that's the
purpose.

The idea is to put a 12v deep cycle in the dome area like:

12v dc deep cycle battery->inverter->present AC motor. I'm guessing
the soft start device belongs between the battery and inverter. I
found this on the Grainger site:
http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=motor+soft+start+module&op=search&Ntt=motor+soft+start+module&N=0&GlobalSearch=true&sst=subset


I got there by searching for soft start module. The inverter is a
Tripp-lite 1250W unit. The tech I talked to at Grainger didn't know
much about these devices. Where does it go in the line, and how does
it get connected to the devices on either side of it?

Bonus question.
For the rotation of the dome, I can still use the AC motor. (BTW a
circuit board goes on the dome and skirt, and the one on the skirt
connects to a PC by a RS-232 connection. The PC software controls both
motors.) There's a hand switch on the edge of the skirt that one
pushes either left or right to make the dome rotate. It needs to be
replaced a power relay. I think this might do the trick
http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=2DR99&op=search&Ntt=2DR99&N=0&GlobalSearch=true&sst=subset>.
Presently 8 lines go out of the switch to the motor. 5 to the motor,
and 3 to a shutter limit switch.

Comments?

Slip rings.

Jamie

Too late. I'm invested in MaxDomeII. I've had enough trouble finding

someone that can do this, as it is. A friend 30 miles from here in a
similar arrangement used slip rings, but he actually found someone to do it.

I have a fellow who I think can do it, but he has other jobs, but will
get back to me next week. I'm just looking for and buying parts while
he's off on other work. Thankfully a fellow in Hawaii has been able to
give me some clues to how to go about this.

Do you use slip rings?

 

[Peter Bennett]

On Wed, 11 Apr 2012 16:18:07 -0700, "W. eWatson"
<wolftracks@invalid.com> wrote:

On 4/11/2012 2:37 PM, Jamie wrote:
W. eWatson wrote:
Back to my dome. I had a six week trip outage and am coming up to
speed by reviewing matters.

For the shutter motor, he idea is to not be dependent upon AC for it,
since the AC motor has a power cord to the area below the dome, the
skirt, and attaches to the skirt where the AC power is. The cord can
get tangled on the telescope. Don't want that to happen. The cord must
go.

A fellow quite far from me who knows this stuff well suggested that to
power the shutter movement. He's not always available.

He says I might need something called a soft start module to avert a
high power need when the dome first starts to move. I think that's the
purpose.

The idea is to put a 12v deep cycle in the dome area like:

12v dc deep cycle battery->inverter->present AC motor. I'm guessing
the soft start device belongs between the battery and inverter. I
found this on the Grainger site:
http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=motor+soft+start+module&op=search&Ntt=motor+soft+start+module&N=0&GlobalSearch=true&sst=subset

The soft start device would go between the motor power switch and the
motor. The Crydom catalog indicates that the SST120 must be used with
another Crydom device - check datasheets and other info from the maker
BEFORE you buy it!

I got there by searching for soft start module. The inverter is a
Tripp-lite 1250W unit. The tech I talked to at Grainger didn't know
much about these devices. Where does it go in the line, and how does
it get connected to the devices on either side of it?

Bonus question.
For the rotation of the dome, I can still use the AC motor. (BTW a
circuit board goes on the dome and skirt, and the one on the skirt
connects to a PC by a RS-232 connection. The PC software controls both
motors.) There's a hand switch on the edge of the skirt that one
pushes either left or right to make the dome rotate. It needs to be
replaced a power relay. I think this might do the trick
http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=2DR99&op=search&Ntt=2DR99&N=0&GlobalSearch=true&sst=subset>.
Presently 8 lines go out of the switch to the motor. 5 to the motor,
and 3 to a shutter limit switch.

I think you'll need two relays - one for each direction, or one to
select direction, and another to start/stop the motor. (and probably
more relays to deal with the limit switches.)

Comments?

Slip rings.

Jamie

Too late. I'm invested in MaxDomeII. I've had enough trouble finding
someone that can do this, as it is. A friend 30 miles from here in a
similar arrangement used slip rings, but he actually found someone to do it.

I have a fellow who I think can do it, but he has other jobs, but will
get back to me next week. I'm just looking for and buying parts while
he's off on other work. Thankfully a fellow in Hawaii has been able to
give me some clues to how to go about this.

Do you use slip rings?

--
Peter Bennett, VE7CEI
peterbb (at) telus.net
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

 

[W. eWatson]

On 4/11/2012 5:56 PM, Peter Bennett wrote:

On Wed, 11 Apr 2012 16:18:07 -0700, "W. eWatson"
wolftracks@invalid.com> wrote:

On 4/11/2012 2:37 PM, Jamie wrote:
W. eWatson wrote:
Back to my dome. I had a six week trip outage and am coming up to
speed by reviewing matters.
....
12v dc deep cycle battery->inverter->present AC motor. I'm guessing
the soft start device belongs between the battery and inverter. I
found this on the Grainger site:
http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=motor+soft+start+module&op=search&Ntt=motor+soft+start+module&N=0&GlobalSearch=true&sst=subset

Well, I think I guessed wrong. First, "12v dc deep cycle

battery->inverter->present AC motor" is not quite right. The 12 v dc
battery powers the circuit card. The card is connected to a PC by a
RS-232 cable. The PC software operates the card. The circuit card
supports this motor by a + and - dc out connectors to the card. There
are about 24 connectors along its one edge.

I would think the inverter is connected to the +/- then to the inverter.
So what you are saying is that the soft start module belongs between the
card and inverter, which very well that this one does. But the specs say:
Input Voltage DC, Max Input Volts 10, Min Input Volts 3.5, and
Voltage Output AC, Min Output Volts 180, Max Output Volts 280

It shouldn't produce AC output, so I think this is the wrong relay. What
would be a correct one?

There is a limit switch at the top of the shutter. The shutter hits a
bar up there, and it stops the motor. I'm not sure if there really is
one when it closes. I'm looking at a schematic from the mfger of the
shutter drive. It shows only one (Namco) limit switch. The motor does
somehow stop when the shutter reaches the bottom.

The soft start device would go between the motor power switch and the
motor. The Crydom catalog indicates that the SST120 must be used with
another Crydom device - check datasheets and other info from the maker
BEFORE you buy it!
....

 

[Jamie]

W. eWatson wrote:

On 4/11/2012 2:37 PM, Jamie wrote:

W. eWatson wrote:

Back to my dome. I had a six week trip outage and am coming up to
speed by reviewing matters.

For the shutter motor, he idea is to not be dependent upon AC for it,
since the AC motor has a power cord to the area below the dome, the
skirt, and attaches to the skirt where the AC power is. The cord can
get tangled on the telescope. Don't want that to happen. The cord must
go.

A fellow quite far from me who knows this stuff well suggested that to
power the shutter movement. He's not always available.

He says I might need something called a soft start module to avert a
high power need when the dome first starts to move. I think that's the
purpose.

The idea is to put a 12v deep cycle in the dome area like:

12v dc deep cycle battery->inverter->present AC motor. I'm guessing
the soft start device belongs between the battery and inverter. I
found this on the Grainger site:
http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=motor+soft+start+module&op=search&Ntt=motor+soft+start+module&N=0&GlobalSearch=true&sst=subset



I got there by searching for soft start module. The inverter is a
Tripp-lite 1250W unit. The tech I talked to at Grainger didn't know
much about these devices. Where does it go in the line, and how does
it get connected to the devices on either side of it?

Bonus question.
For the rotation of the dome, I can still use the AC motor. (BTW a
circuit board goes on the dome and skirt, and the one on the skirt
connects to a PC by a RS-232 connection. The PC software controls both
motors.) There's a hand switch on the edge of the skirt that one
pushes either left or right to make the dome rotate. It needs to be
replaced a power relay. I think this might do the trick
http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=2DR99&op=search&Ntt=2DR99&N=0&GlobalSearch=true&sst=subset>.

Presently 8 lines go out of the switch to the motor. 5 to the motor,
and 3 to a shutter limit switch.

Comments?

Slip rings.

Jamie

Too late. I'm invested in MaxDomeII. I've had enough trouble finding
someone that can do this, as it is. A friend 30 miles from here in a
similar arrangement used slip rings, but he actually found someone to do
it.

I have a fellow who I think can do it, but he has other jobs, but will
get back to me next week. I'm just looking for and buying parts while
he's off on other work. Thankfully a fellow in Hawaii has been able to
give me some clues to how to go about this.

Do you use slip rings?

I don't have an observatory dome, I don't do such things however, I do
have slip rings lying around here

If you had a lathe around, you could make you're own.. Get some
micarta and soft brass tubing and the way you go. Of course, you'd
also need to get some brushes and holders.

All doable if you really are serious.

Jamie

 

[Randy Day]

In article <jm4ic0$9ej$1@dont-email.me>, wolftracks@invalid.com says...

[snip]

He says I might need something called a soft start module to avert a
high power need when the dome first starts to move. I think that's the
purpose.
12v dc deep cycle battery->inverter->present AC motor. I'm guessing the
soft start device belongs between the battery and inverter. I found this

Soft start applies gradually increasing power to
accelerate the load more slowly, as opposed to a
motor using a power surge to kick the load into
motion. If you can tolerate a gradual acceleration,
an SSM sould work.

Googling on "soft start module" brought up all kinds of
modules for DC and AC applications. Be very careful what
you buy. You want an AC motor SSM, between the inverter
and the motor. Putting something between battery and
inverter will almost certainly mess up the inverter.
Possibly permanently.

It needs to be replaced a
power relay. I think this might do the trick
http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=2DR99&op=search&Ntt=2DR99&N=0&GlobalSearch=true&sst=subset>.

If you can find one, go for a Solid State Relay.
You want to reduce power consumption in your project,
and the wire coil of a standard relay sucks power like
crazy.

 

[John G]

After serious thinking W. eWatson wrote :

On 4/11/2012 5:56 PM, Peter Bennett wrote:
On Wed, 11 Apr 2012 16:18:07 -0700, "W. eWatson"
wolftracks@invalid.com> wrote:

On 4/11/2012 2:37 PM, Jamie wrote:
W. eWatson wrote:
Back to my dome. I had a six week trip outage and am coming up to
speed by reviewing matters.
...
12v dc deep cycle battery->inverter->present AC motor. I'm guessing
the soft start device belongs between the battery and inverter. I
found this on the Grainger site:
http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=motor+soft+start+module&op=search&Ntt=motor+soft+start+module&N=0&GlobalSearch=true&sst=subset

Well, I think I guessed wrong. First, "12v dc deep cycle
battery->inverter->present AC motor" is not quite right. The 12 v dc battery
powers the circuit card. The card is connected to a PC by a RS-232 cable. The
PC software operates the card. The circuit card supports this motor by a +
and - dc out connectors to the card. There are about 24 connectors along its
one edge.

I would think the inverter is connected to the +/- then to the inverter. So
what you are saying is that the soft start module belongs between the card
and inverter, which very well that this one does. But the specs say:
Input Voltage DC, Max Input Volts 10, Min Input Volts 3.5, and
Voltage Output AC, Min Output Volts 180, Max Output Volts 280

It shouldn't produce AC output, so I think this is the wrong relay. What
would be a correct one?

There is a limit switch at the top of the shutter. The shutter hits a bar up
there, and it stops the motor. I'm not sure if there really is one when it
closes. I'm looking at a schematic from the mfger of the shutter drive. It
shows only one (Namco) limit switch. The motor does somehow stop when the
shutter reaches the bottom.


The soft start device would go between the motor power switch and the
motor. The Crydom catalog indicates that the SST120 must be used with
another Crydom device - check datasheets and other info from the maker
BEFORE you buy it!
...

I hope you can take this in a constructive way, please.
I know these Newsgroups are for people to ask questions but from all I
have read of your problem you do not have enough understanding of
electric circuits to be asking the questions you are.

The Input to the SSR, you reference, is the control voltage and the
output is what it will switch as is the case with most relays.
Is your supply to this motor 120 volts or 240 volts. Hell! I cannot
remember and if it is 120 this is not the relay for you under any
circustanses.
This SSR is Obsolete.

The problem is too large to just ask "Can I use this or that?" when
neither you nor anyone reading your questions has a reasonable
understanding of the overall plan or requirements.

I am saying this in the hope that it will save you doing something
dangerous or costly because "We" did not have the full picture.

--
John G

 

[W. eWatson]

....

I hope you can take this in a constructive way, please.
I know these Newsgroups are for people to ask questions but from all I
have read of your problem you do not have enough understanding of
electric circuits to be asking the questions you are.

The Input to the SSR, you reference, is the control voltage and the
output is what it will switch as is the case with most relays.
Is your supply to this motor 120 volts or 240 volts. Hell! I cannot
remember and if it is 120 this is not the relay for you under any
circustanses.
This SSR is Obsolete.

The problem is too large to just ask "Can I use this or that?" when
neither you nor anyone reading your questions has a reasonable
understanding of the overall plan or requirements.

I am saying this in the hope that it will save you doing something
dangerous or costly because "We" did not have the full picture.

All I'm trying to do is understand what equipment is needed given some
few words I see on schematics, so that I can order it after I've checked
with my electrician who will do the job when he is done working on some
other jobs. I'd like to get some of the parts at least before he really
gets started.

However, it's become obvious to me that I simply cannot go to a web site
like Grainger and fullfill the part needs of this project. Some that I
have talked to have no idea what soft start module is.

 

[W. eWatson]

....

I have a fellow who I think can do it, but he has other jobs, but will
get back to me next week. I'm just looking for and buying parts while
he's off on other work. Thankfully a fellow in Hawaii has been able to
give me some clues to how to go about this.

Do you use slip rings?

I don't have an observatory dome, I don't do such things however, I do
have slip rings lying around here

If you had a lathe around, you could make you're own.. Get some micarta
and soft brass tubing and the way you go. Of course, you'd
also need to get some brushes and holders.

All doable if you really are serious.

Jamie


Thanks, but I'll pass on that.

 

[ehsjr]

W. eWatson wrote:

Back to my dome. I had a six week trip outage and am coming up to speed
by reviewing matters.

For the shutter motor, he idea is to not be dependent upon AC for it,
since the AC motor has a power cord to the area below the dome, the
skirt, and attaches to the skirt where the AC power is. The cord can get
tangled on the telescope. Don't want that to happen. The cord must go.

A fellow quite far from me who knows this stuff well suggested that to
power the shutter movement. He's not always available.

He says I might need something called a soft start module to avert a
high power need when the dome first starts to move. I think that's the
purpose.

The idea is to put a 12v deep cycle in the dome area like:

12v dc deep cycle battery->inverter->present AC motor. I'm guessing the
soft start device belongs between the battery and inverter. I found this
on the Grainger site:
http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=motor+soft+start+module&op=search&Ntt=motor+soft+start+module&N=0&GlobalSearch=true&sst=subset

That's wrong for at least two reasons, and possibly more.
First, you do _not_ want to put any soft start device between
the battery and the inverter.

Second, the Grainger site shows that the _minimum_ output voltage
from the soft start relay is 180 volts, and it's AC. Your battery
provides only 12 volts, DC. There is no way that relay will work
between the battery and the inverter. The soft start relay,
if used at all, must be connected between the output of the
inverter and the motor and the inverter must supply at least
180 volts AC.

Aside from that, you need to determine whether soft start is
needed for the circuit.

I got there by searching for soft start module. The inverter is a
Tripp-lite 1250W unit. The tech I talked to at Grainger didn't know much
about these devices. Where does it go in the line, and how does it get
connected to the devices on either side of it?

battery====inverter=======relay===soft start===motor
| |
===controller

The above shows where it goes in the line. I assume your
controller plugs into the inverter, too.

You need the exact specs on all the devices to draw a specific
wiring diagram. Right now, we don't even know whether a soft
start relay will be used.

Bonus question.
For the rotation of the dome, I can still use the AC motor. (BTW a
circuit board goes on the dome and skirt, and the one on the skirt
connects to a PC by a RS-232 connection. The PC software controls both
motors.) There's a hand switch on the edge of the skirt that one pushes
either left or right to make the dome rotate. It needs to be replaced a
power relay. I think this might do the trick
http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=2DR99&op=search&Ntt=2DR99&N=0&GlobalSearch=true&sst=subset>.

That is a latching relay. You may want a non-latching relay.
A latching relay is like a light switch - once you turn it on
it stays on, until you turn it off. (Your controller turns
the relay on/off). A non latching relay is like a doorbell
switch. The bell rings when you push the button and stops
ringing when you release it. Your controller design dictates
which kind of relay you need. If you can use a non-latching
relay with your controller, it will cost you a lot less than
the $67.00 Square-D relay.

Presently 8 lines go out of the switch to the motor. 5 to the motor, and
3 to a shutter limit switch.

I'm guessing that one of the 5 wires to the motor is ground, and
the other four are connected to two coils inside the motor.
You'll need to get the datasheet for the motor, or the LRA
(Locked Rotor Amps) spec from its nameplate to determine whether
soft start is needed. If your controller plugs into the inverter
as I assumed, you need to add the current it draws to the motor
LRA spec, and if that total is less than the peak output current
rating of the inverter, no soft start is needed. If the controller
is powered directly from the battery, then the current it draws
is irrelevant to determining whether soft start is needed.

Ed

Comments?

 

[W. eWatson]

Well, there's no longer any need to worry about this. I have a second
guy, CE, who is located far from me, 2000 miles, who guided me toward
some aspects of this. I hadn't heard from him for 4-5 days, and he just
came through big time to tell which of the heavy duty parts I need, and
where to find them.

When I bought that MaxDome II circuit cards, I quickly found out the
mfger really had little to say about providing details for this dome.
Mostly they provide help about the two circuit cards. CE stepped in when
I was posting on their forum. He definitely knows how to do this. Too
bad he's not a lot closer.

Cheers.

 

[newshound]

On 12/04/2012 03:37, Jamie wrote:

W. eWatson wrote:

Do you use slip rings?

I don't have an observatory dome, I don't do such things however, I do
have slip rings lying around here

If you had a lathe around, you could make you're own.. Get some micarta
and soft brass tubing and the way you go. Of course, you'd
also need to get some brushes and holders.

All doable if you really are serious.

Jamie


Unless it's an odd sort of dome with a central axle, it would need a

rather large lathe