Forums

Soft Start Module, Inverter and Motor--Observatory Dome

Started by W. eWatson April 11, 2012
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?

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
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?
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
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!
...
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
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.
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
...
> > 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.
...
>> 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.