Thanks to the control station turning AO-16 back on. Heard the sequence and then the bird was really kicking butt on its signal. I lowered my power to 5 watts and was still banging in and this with some very "bad" verticals that I have difficulty with on the other birds. Heard to satellite quit during the pass and then obviously, control station came back and turned it on again. Other then some "junk" only a couple of stations were on.
I had a choice of AO-16 or SO-50. No brainer, stuck with AO-16. Good work fellows,
73, Reid, W4UPD
My pleasure Reid. Up until today I had been optimistic about maybe eeking some sort of continuing operation out of AO-16, but this pass has sort of killed that. We had been getting an orbit or two between shutdowns the last week or so, which led me to think if we could enable it every orbit we'd extend operations. Right now the satellite is in about 79% sun, by this summer that will drop to 68%. Illumination equals heat, and our reset problem is temperature dependent. The temperatures have already dropped enough that the satellite reset twice during that pass; the time you heard, and about 30 seconds after I first turned it on it did the same.
So...we'll have to see if even a large effort will result in any sort of usable operations as we approach that 68% number.
73, Drew KO4MA AMSAT-NA VP Operations
PS Be sure to thank Mark, N8MH, when you hear him on the air. He is usually the one that turns the satellite on in the afternoons, not me!
----- Original Message ----- From: "w4upd" updwrb@bristor-assoc.com To: "Amsat-Bb@Amsat. Org" amsat-bb@amsat.org Sent: Tuesday, December 30, 2008 3:58 PM Subject: [amsat-bb] AO-16 back on and very strong
Thanks to the control station turning AO-16 back on. Heard the sequence and then the bird was really kicking butt on its signal. I lowered my power to 5 watts and was still banging in and this with some very "bad" verticals that I have difficulty with on the other birds. Heard to satellite quit during the pass and then obviously, control station came back and turned it on again. Other then some "junk" only a couple of stations were on.
I had a choice of AO-16 or SO-50. No brainer, stuck with AO-16. Good work fellows,
73, Reid, W4UPD
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Hi Drew,
I'm sure you and the command team have already looked into this, but are there any "knobs" to turn that could indirectly warm up the satellite a bit? What comes to mind is to reduce the Transmit power. I think you used the reverse process to cool off AO-51 earlier this year (higher power draw cools off solar cells).
Just a thought,
Greg KO6TH
From: glasbrenner@mindspring.com To: updwrb@bristor-assoc.com; amsat-bb@amsat.org Date: Tue, 30 Dec 2008 16:26:15 -0500 Subject: [amsat-bb] Re: AO-16 back on and very strong
My pleasure Reid. Up until today I had been optimistic about maybe eeking some sort of continuing operation out of AO-16, but this pass has sort of killed that. We had been getting an orbit or two between shutdowns the last week or so, which led me to think if we could enable it every orbit we'd extend operations. Right now the satellite is in about 79% sun, by this summer that will drop to 68%. Illumination equals heat, and our reset problem is temperature dependent. The temperatures have already dropped enough that the satellite reset twice during that pass; the time you heard, and about 30 seconds after I first turned it on it did the same.
So...we'll have to see if even a large effort will result in any sort of usable operations as we approach that 68% number.
73, Drew KO4MA AMSAT-NA VP Operations
PS Be sure to thank Mark, N8MH, when you hear him on the air. He is usually the one that turns the satellite on in the afternoons, not me!
----- Original Message ----- From: "w4upd" updwrb@bristor-assoc.com To: "Amsat-Bb@Amsat. Org" amsat-bb@amsat.org Sent: Tuesday, December 30, 2008 3:58 PM Subject: [amsat-bb] AO-16 back on and very strong
Thanks to the control station turning AO-16 back on. Heard the sequence and then the bird was really kicking butt on its signal. I lowered my power to 5 watts and was still banging in and this with some very "bad" verticals that I have difficulty with on the other birds. Heard to satellite quit during the pass and then obviously, control station came back and turned it on again. Other then some "junk" only a couple of stations were on.
I had a choice of AO-16 or SO-50. No brainer, stuck with AO-16. Good work fellows,
73, Reid, W4UPD
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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Indeed we have discussed it, and will try it. To be honest, it didn't make as much difference temperature-wise as I thought it would on AO-51, but it's worth a shot.
73, Drew KO4MA
Hi Drew,
I'm sure you and the command team have already looked into this, but are there any "knobs" to turn that could indirectly warm up the satellite a bit? What comes to mind is to reduce the Transmit power. I think you used the reverse process to cool off AO-51 earlier this year (higher power draw cools off solar cells).
Just a thought,
Greg KO6TH
Have a G-5500 and suddenly the rotor stops moving clock-wise past 180. I stood under it and it makes no particular noises at that point, just stops perfectly at 180. Was working the day before and flawlessly for the last 4 years.
It stops so quietly, it almost sounds like the limit switch or the controller is stopping the motor. The elevation works perfectly and the rotation works fine from zero to 180. If it were a bad gear or something like that, I would expect it to grind or make some funny sounds
It is a royal pain to take the thing down; any ideas on debugging without taking the thing down?
Michael
Michael Hatzakis Jr MD wrote:
Have a G-5500 and suddenly the rotor stops moving clock-wise past 180. I stood under it and it makes no particular noises at that point, just stops perfectly at 180. Was working the day before and flawlessly for the last 4 years.
It stops so quietly, it almost sounds like the limit switch or the controller is stopping the motor. The elevation works perfectly and the rotation works fine from zero to 180. If it were a bad gear or something like that, I would expect it to grind or make some funny sounds
It is a royal pain to take the thing down; any ideas on debugging without taking the thing down?
Michael
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I cannot evaluate this, however, mine stops at 180 clockwise or counterclockwise. You must have put it up with 180 as the middle of the rotation. Make sure none of your cables have become loose and is preventing this from turning. Insure that 0 degrees is still correctly pointing as I've seen the lower unit slip on the pipe (if it is installed this way) from loose bolts. Good luck and let us know what you do find as the problem. 73, Dee, NB2F
To differentiate between a stuck gear or the limit switch (or similar), can you measure the drive current going to the rotor? If it goes up at the 180 mark, it's a jam; if it goes to zero, it's the limit switch.
Also, what does the controller's meter indicate? Maybe it's shutting it down for some reason.
Greg KO6TH
From: mail@hatzakis.net To: amsat-bb@amsat.org Date: Thu, 1 Jan 2009 14:10:41 -0800 Subject: [amsat-bb] G-5500 stuck problem
Have a G-5500 and suddenly the rotor stops moving clock-wise past 180. I stood under it and it makes no particular noises at that point, just stops perfectly at 180. Was working the day before and flawlessly for the last 4 years.
It stops so quietly, it almost sounds like the limit switch or the controller is stopping the motor. The elevation works perfectly and the rotation works fine from zero to 180. If it were a bad gear or something like that, I would expect it to grind or make some funny sounds
It is a royal pain to take the thing down; any ideas on debugging without taking the thing down?
Michael
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Hi Greg, Actually you need to measure the current while it is moving, then if it drops a little then its a jam, if it goes to zero then its the limit switch.
I know this goes against reasoning, you expect a locked motor to pull more current, but these are split winding AC motors with a capacitor and they act differently.
This is also why when you get a cable snag you burn up the motor or the transformer or both before you blow the fuse, that fuse I think just saves you from a mis-wired or shorted cable.
73 Kevin WA6FWF
----- Original Message ----- From: "Greg D." ko6th_greg@hotmail.com To: mail@hatzakis.net; amsat-bb@amsat.org Sent: Thursday, January 01, 2009 5:58 PM Subject: [amsat-bb] Re: G-5500 stuck problem
To differentiate between a stuck gear or the limit switch (or similar), can you measure the drive current going to the rotor? If it goes up at the 180 mark, it's a jam; if it goes to zero, it's the limit switch.
Also, what does the controller's meter indicate? Maybe it's shutting it down for some reason.
Greg KO6TH
Ha, really... Thanks, I was "sure" it was the other way around.
So, if the current drops a little on a jam, why would it burn up either the transformer or motor?
Greg KO6TH
From: wa6fwf@sbcglobal.net To: amsat-bb@amsat.org Date: Thu, 1 Jan 2009 18:42:15 -0800 Subject: [amsat-bb] Re: G-5500 stuck problem
Hi Greg, Actually you need to measure the current while it is moving, then if it drops a little then its a jam, if it goes to zero then its the limit switch.
I know this goes against reasoning, you expect a locked motor to pull more current, but these are split winding AC motors with a capacitor and they act differently.
This is also why when you get a cable snag you burn up the motor or the transformer or both before you blow the fuse, that fuse I think just saves you from a mis-wired or shorted cable.
73 Kevin WA6FWF
----- Original Message ----- From: "Greg D." ko6th_greg@hotmail.com To: mail@hatzakis.net; amsat-bb@amsat.org Sent: Thursday, January 01, 2009 5:58 PM Subject: [amsat-bb] Re: G-5500 stuck problem
To differentiate between a stuck gear or the limit switch (or similar), can you measure the drive current going to the rotor? If it goes up at the 180 mark, it's a jam; if it goes to zero, it's the limit switch.
Also, what does the controller's meter indicate? Maybe it's shutting it down for some reason.
Greg KO6TH
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Hi Greg, these transformers and motors are rated for intermittent duty so getting them stuck and left that way kills them, if memory serves they pull about 1.7 amps running, and drop to about 1.2 amps stalled, 1.2amps x 25v = 30 watts and over time that heat builds up and fries the windings.
It's just a oddity of this particular type of ac motor that it behaves this way, if it was another type or a dc motor you would see the current rise that you expected and fuses would pop.
I found this out when I was making a add on card to my LVB tracker to replace the G-5500 control box, I thought I would be slick and add one of the PPTC resettable fuses on the motors, so I needed to know the running current and locked current so I could pick the right one, I was also surprised when the current dropped a little instead of going up, and then doing some reading on the web about dual winding AC motors that use a capacitor to phase shift the other winding explained why this happens.
73 Kevin WA6FWF
----- Original Message ----- From: "Greg D." ko6th_greg@hotmail.com To: wa6fwf@sbcglobal.net; amsat-bb@amsat.org Sent: Thursday, January 01, 2009 7:04 PM Subject: RE: [amsat-bb] Re: G-5500 stuck problem
Ha, really... Thanks, I was "sure" it was the other way around.
So, if the current drops a little on a jam, why would it burn up either the transformer or motor?
Greg KO6TH
From: wa6fwf@sbcglobal.net To: amsat-bb@amsat.org Date: Thu, 1 Jan 2009 18:42:15 -0800 Subject: [amsat-bb] Re: G-5500 stuck problem
Hi Greg, Actually you need to measure the current while it is moving, then if it drops a little then its a jam, if it goes to zero then its the limit switch.
I know this goes against reasoning, you expect a locked motor to pull more current, but these are split winding AC motors with a capacitor and they act differently.
This is also why when you get a cable snag you burn up the motor or the transformer or both before you blow the fuse, that fuse I think just saves you from a mis-wired or shorted cable.
73 Kevin WA6FWF
.
Hi Kevin,
So, my take-away here is that it's not the stall itself that is the problem; the motor is practically designed to self-destruct. Simply running the rotor back and forth enough times will do the same thing. In fact, probably worse, given the higher draw.
One thing just occurred to me... AC current measurements assume a specific phase relationship between voltage and current - power factor, I think they call it. This is a highly inductive load, and the phase-shift capacitor throws another unknown into the puzzle. I wonder if the two measurements you took are real? It could be that you think that the running current is higher, when it may just be a measurement error. How were they measured?
Greg KO6TH
From: wa6fwf@sbcglobal.net To: amsat-bb@amsat.org Date: Thu, 1 Jan 2009 20:51:47 -0800 Subject: [amsat-bb] Re: G-5500 stuck problem
Hi Greg, these transformers and motors are rated for intermittent duty so getting them stuck and left that way kills them, if memory serves they pull about 1.7 amps running, and drop to about 1.2 amps stalled, 1.2amps x 25v = 30 watts and over time that heat builds up and fries the windings.
It's just a oddity of this particular type of ac motor that it behaves this way, if it was another type or a dc motor you would see the current rise that you expected and fuses would pop.
I found this out when I was making a add on card to my LVB tracker to replace the G-5500 control box, I thought I would be slick and add one of the PPTC resettable fuses on the motors, so I needed to know the running current and locked current so I could pick the right one, I was also surprised when the current dropped a little instead of going up, and then doing some reading on the web about dual winding AC motors that use a capacitor to phase shift the other winding explained why this happens.
73 Kevin WA6FWF
----- Original Message ----- From: "Greg D." ko6th_greg@hotmail.com To: wa6fwf@sbcglobal.net; amsat-bb@amsat.org Sent: Thursday, January 01, 2009 7:04 PM Subject: RE: [amsat-bb] Re: G-5500 stuck problem
Ha, really... Thanks, I was "sure" it was the other way around.
So, if the current drops a little on a jam, why would it burn up either the transformer or motor?
Greg KO6TH
From: wa6fwf@sbcglobal.net To: amsat-bb@amsat.org Date: Thu, 1 Jan 2009 18:42:15 -0800 Subject: [amsat-bb] Re: G-5500 stuck problem
Hi Greg, Actually you need to measure the current while it is moving, then if it drops a little then its a jam, if it goes to zero then its the limit switch.
I know this goes against reasoning, you expect a locked motor to pull more current, but these are split winding AC motors with a capacitor and they act differently.
This is also why when you get a cable snag you burn up the motor or the transformer or both before you blow the fuse, that fuse I think just saves you from a mis-wired or shorted cable.
73 Kevin WA6FWF
.
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Hi Greg, Yes these will burn up on their own, page 2 of the manual states that the maximum continuous run time is 5 mins, but when normally tracking a sat were talking little movements of a couple of seconds. I was measuring current with a standard VOM set for AC current and I had no way of measuring the PF so what you say could be correct and I wasn't seeing the real current, and I'm not a motor guru but from what I understand the capacitor and the winding 90deg out of phase are only needed to get the motor spinning and turning in the direction that you want, that once the motor is up to speed you could disconnect the capacitor and 90 deg winding and the motor would keep running, also the capacitor value needed to start vs. the most efficient to run at "if you were going to leave the circuit engaged" are two completely different values, and the current rise at run speed are caused by the mis-match. So when you lock the rotor you are in start mode at x current and when your up to speed your seeing the mismatch/inefficiency and the increased current flow.
Maybe there is someone on here that could do a better job of explaining why this motor works like this.
I don't remember the original sites I went to but a couple links that you might want to check out...
http://www.lmphotonics.com/single_phase_m.htm
http://www.allaboutcircuits.com/vol_2/chpt_13/9.html
73 Kevin WA6FWF
----- Original Message ----- From: "Greg D." ko6th_greg@hotmail.com To: wa6fwf@sbcglobal.net; amsat-bb@amsat.org Sent: Thursday, January 01, 2009 11:08 PM Subject: RE: [amsat-bb] Re: G-5500 stuck problem
Hi Kevin,
So, my take-away here is that it's not the stall itself that is the problem; the motor is practically designed to self-destruct. Simply running the rotor back and forth enough times will do the same thing. In fact, probably worse, given the higher draw.
One thing just occurred to me... AC current measurements assume a specific phase relationship between voltage and current - power factor, I think they call it. This is a highly inductive load, and the phase-shift capacitor throws another unknown into the puzzle. I wonder if the two measurements you took are real? It could be that you think that the running current is higher, when it may just be a measurement error. How were they measured?
Greg KO6TH
To All, Antenna rotator motors are capacitor run types. All induction motors shift the phase of the current. The current is nearest to being in phase only when the rotor is locked. An unloaded motor draws almost no power as the current is out of phase with the voltage. As the antenna rotators age, the run capacitor looses capacity causing a reduction in torque from the motor. This capacitor is in the control box, is low cost and the first thing that should be replaces if the rotator is slowing down. Typically the run capacitor only lasts for 10 years of service. TV antenna rotators did not last that long but the Amateur Radio antenna rotators will often outlast the run capacitor.
Art, KC6UQH
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Greg D. Sent: Thursday, January 01, 2009 11:09 PM To: wa6fwf@sbcglobal.net; amsat-bb@amsat.org Subject: [amsat-bb] Re: G-5500 stuck problem
Hi Kevin,
So, my take-away here is that it's not the stall itself that is the problem; the motor is practically designed to self-destruct. Simply running the rotor back and forth enough times will do the same thing. In fact, probably worse, given the higher draw.
One thing just occurred to me... AC current measurements assume a specific phase relationship between voltage and current - power factor, I think they call it. This is a highly inductive load, and the phase-shift capacitor throws another unknown into the puzzle. I wonder if the two measurements you took are real? It could be that you think that the running current is higher, when it may just be a measurement error. How were they measured?
Greg KO6TH
From: wa6fwf@sbcglobal.net To: amsat-bb@amsat.org Date: Thu, 1 Jan 2009 20:51:47 -0800 Subject: [amsat-bb] Re: G-5500 stuck problem
Hi Greg, these transformers and motors are rated for intermittent duty so getting
them stuck and left that way kills them, if memory serves
they pull about 1.7 amps running, and drop to about 1.2 amps stalled,
1.2amps x 25v = 30 watts and over time that heat builds up and
fries the windings.
It's just a oddity of this particular type of ac motor that it behaves
this way, if it was another type or a dc motor you would see
the current rise that you expected and fuses would pop.
I found this out when I was making a add on card to my LVB tracker to
replace the G-5500 control box, I thought I would be slick
and add one of the PPTC resettable fuses on the motors, so I needed to
know the running current and locked current so I could pick
the right one, I was also surprised when the current dropped a little
instead of going up, and then doing some reading on the web
about dual winding AC motors that use a capacitor to phase shift the
other winding explained why this happens.
73 Kevin WA6FWF
----- Original Message ----- From: "Greg D." ko6th_greg@hotmail.com To: wa6fwf@sbcglobal.net; amsat-bb@amsat.org Sent: Thursday, January 01, 2009 7:04 PM Subject: RE: [amsat-bb] Re: G-5500 stuck problem
Ha, really... Thanks, I was "sure" it was the other way around.
So, if the current drops a little on a jam, why would it burn up either
the transformer or motor?
Greg KO6TH
From: wa6fwf@sbcglobal.net To: amsat-bb@amsat.org Date: Thu, 1 Jan 2009 18:42:15 -0800 Subject: [amsat-bb] Re: G-5500 stuck problem
Hi Greg, Actually you need to measure the current while it is moving, then if
it drops a little then its a jam, if it goes to zero then
its the limit switch.
I know this goes against reasoning, you expect a locked motor to pull
more current, but these are split winding AC motors with a
capacitor and they act differently.
This is also why when you get a cable snag you burn up the motor or the
transformer or both before you blow the fuse, that fuse I
think just saves you from a mis-wired or shorted cable.
73 Kevin WA6FWF
.
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_________________________________________________________________ Life on your PC is safer, easier, and more enjoyable with Windows VistaR. http://clk.atdmt.com/MRT/go/127032870/direct/01/ _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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Will do Drew. Especially if I hear him on AO-16. I knew it had a good receive, but wow, the transmit was good so that I could hear it on my crummy verticals. I really do need to get the arrays back up that have been down since the storms of '04' and I'm finding that a couple of birds it would be very beneficial (especially for AO-7). Again, I took my power into a homebrew 1/4 ground plane down to 5 watts and was still hearing quite a signal. My goal is to try and use this bird as much as I can until it goes away.
Again Drew, thanks for your and other's efforts on this. It really makes operating the birds fun. Especially when those of us are too lazy to put the better antenna up or back up, hi.
Andrew Glasbrenner wrote:
My pleasure Reid. Up until today I had been optimistic about maybe eeking some sort of continuing operation out of AO-16, but this pass has sort of killed that. We had been getting an orbit or two between shutdowns the last week or so, which led me to think if we could enable it every orbit we'd extend operations. Right now the satellite is in about 79% sun, by this summer that will drop to 68%. Illumination equals heat, and our reset problem is temperature dependent. The temperatures have already dropped enough that the satellite reset twice during that pass; the time you heard, and about 30 seconds after I first turned it on it did the same.
So...we'll have to see if even a large effort will result in any sort of usable operations as we approach that 68% number.
73, Drew KO4MA AMSAT-NA VP Operations
PS Be sure to thank Mark, N8MH, when you hear him on the air. He is usually the one that turns the satellite on in the afternoons, not me!
----- Original Message ----- From: "w4upd" updwrb@bristor-assoc.com To: "Amsat-Bb@Amsat. Org" amsat-bb@amsat.org Sent: Tuesday, December 30, 2008 3:58 PM Subject: [amsat-bb] AO-16 back on and very strong
Thanks to the control station turning AO-16 back on. Heard the sequence and then the bird was really kicking butt on its signal. I lowered my power to 5 watts and was still banging in and this with some very "bad" verticals that I have difficulty with on the other birds. Heard to satellite quit during the pass and then obviously, control station came back and turned it on again. Other then some "junk" only a couple of stations were on.
I had a choice of AO-16 or SO-50. No brainer, stuck with AO-16. Good work fellows,
73, Reid, W4UPD
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
participants (7)
-
Andrew Glasbrenner -
Art McBride -
Dee -
Greg D. -
Michael Hatzakis Jr MD -
w4upd -
wa6fwf