Motor Stall quick help needed


Joel Short
 

I have a 2017 AP1100GTO CP4, operating with the ASCOM driver and I'm getting a motor stall warning as soon as the motors are unparked and energized.

About a week ago I had a pier crash.  Because of a download issue with my camera SGP never performed an automatic pier flip and I came out in the morning to find the camera crashed into the pier and the mount stalled.

Now the motor (I'm guessing RA) immediately stalls.  This has me very worried.  I thought the motors were protected from something like this?

Any ideas?  It's clear tonight!!!
joel


Joel Short
 

I double checked the cables and made sure they were fully seated.  The LED on the CP4 is green.  I get the motor stall warning when the gear boxes are disengaged from the worm.  I tried re-initializing from Park 3, no go.  
joel


Bill Long
 

Hey Joel,

Do you have the latest firmware installed for the CP4? Should be VCP4-P01-11. Not likely related to your problem, but something to confirm.

-Bill


From: ap-gto@... on behalf of buckeyestargazer@... [ap-gto]
Sent: Friday, March 8, 2019 5:04 PM
To: ap-gto@...
Subject: [ap-gto] Re: Motor Stall quick help needed
 
 

I double checked the cables and made sure they were fully seated.  The LED on the CP4 is green.  I get the motor stall warning when the gear boxes are disengaged from the worm.  I tried re-initializing from Park 3, no go.  

joel


Joel Short
 

Yeah, latest firmware and latest driver.
joel


On Fri, Mar 8, 2019 at 7:09 PM Bill Long bill@... [ap-gto] <ap-gto@...> wrote:
 

Hey Joel,

Do you have the latest firmware installed for the CP4? Should be VCP4-P01-11. Not likely related to your problem, but something to confirm.

-Bill


Roland Christen
 

Remove the cover on the RA gearbox, the one on the side. You will see the geartrain and the motor shaft with small pinion on it. With the power off and the gearbox disengaged from the worm see if the motor shaft turns freely. If it does, turn power on and initialize the mount. Watch the motor shaft to see if it turns slowly at the sidereal rate. If it turns, set the button rate to 64x and press either E or W button. See what the result is - the motor should turn at a higher rate.

Roland



-----Original Message-----
From: buckeyestargazer@... [ap-gto]
To: ap-gto
Sent: Fri, Mar 8, 2019 7:06 pm
Subject: [ap-gto] Re: Motor Stall quick help needed



I double checked the cables and made sure they were fully seated.  The LED on the CP4 is green.  I get the motor stall warning when the gear boxes are disengaged from the worm.  I tried re-initializing from Park 3, no go.  
joel



Roland Christen
 

neither of those will have anything to do with motor Stall.

Howard and I are here at the office all night if you need assistance.

Rolando



-----Original Message-----
From: Joel Short buckeyestargazer@... [ap-gto]
To: ap-gto Sent: Fri, Mar 8, 2019 7:11 pm
Subject: Re: [ap-gto] Re: Motor Stall quick help needed



Yeah, latest firmware and latest driver.
joel

On Fri, Mar 8, 2019 at 7:09 PM Bill Long bill@... [ap-gto] <ap-gto@...> wrote:
 
Hey Joel,

Do you have the latest firmware installed for the CP4? Should be VCP4-P01-11. Not likely related to your problem, but something to confirm.

-Bill




Joel Short
 

Unfortunately the motor shaft does not turn at all (RA).
joel


Steve Reilly
 

Same result if you swap the connectors?

 

 

From: ap-gto@...
Sent: Friday, March 8, 2019 8:26 PM
To: ap-gto@...
Subject: [ap-gto] Re: Motor Stall quick help needed

 

 

Unfortunately the motor shaft does not turn at all (RA).

joel


Roland Christen
 

That is no information. What I asked is for you to turn power off and turn it by hand. Does it turn when you turn it by hand or is the motor shaft frozen?

Roland



-----Original Message-----
From: buckeyestargazer@... [ap-gto]
To: ap-gto
Sent: Fri, Mar 8, 2019 7:25 pm
Subject: [ap-gto] Re: Motor Stall quick help needed



Unfortunately the motor shaft does not turn at all (RA).
joel



Joel Short
 

Sorry, I did as you instructed and the motor shaft does not turn by hand.  Powered off, power cable removed, disengaged from the worm gear.
joel


Roland Christen
 

Unfortunately, it appears then that the motor is toast and needs to be replaced. Apparently the clutches were tight enough but not locked so the motor could still turn but was drawing excess current. Your power supply was also powerful enough to supply the necessary current and the motor never actually stalled and therefore the stall sensing did not activate. Eventually the motor windings overheated and failed.

To avoid that, I would use APCC to control the mount and set limits so that the mount cannot go past the safe zones. All your other software will work nicely with APCC. You don't even need the Pro version.

We are working on an over-current limit for the CP4, but not quite ready for release. It will be released in a future update. Even with that feature i would still use APCC and set limits - best to have backups with any unattended mount.

I suggest calling the office tomorrow and talk with either George or Christine to get your motor fixed.

Roland





-----Original Message-----
From: buckeyestargazer@... [ap-gto]
To: ap-gto
Sent: Fri, Mar 8, 2019 7:33 pm
Subject: [ap-gto] Re: Motor Stall quick help needed



Sorry, I did as you instructed and the motor shaft does not turn by hand.  Powered off, power cable removed, disengaged from the worm gear.
joel



Joel Short
 

I was afraid it would be something like that.  I'll call tomorrow to get it fixed.

When the pier crash happened it was a (un)perfect storm of events that happened to cause the problem.  Several things didn't happen that should have happened, including an alert that would wake me when there's a problem.  I'm guessing this scenario would only happen 1/100,000 times and it's just my luck.

Could you explain a bit more what you mean by "Apparently the clutches were tight enough but not locked..."?  I tightened the clutches by hand as hard as I could.  Does that not "lock" the axes?  

joel


Roland Christen
 


I tightened the clutches by hand as hard as I could.  Does that not "lock" the axes?  
The motors can still overcome a hand tight clutch.

You need APCC and build limits. Your best bet for unattended. The only other way is a simple hour timer which has a 110 volt plug and will turn off power at a preset time.

Tomorrow is Saturday and the office phones won't be answered. Send AP an e-mail and I'll get Christine on it. meanwhile remove the motor from the gearbox and send it in. Send the motor, internal wires and back panel all as one piece.

Roland


-----Original Message-----
From: buckeyestargazer@... [ap-gto]
To: ap-gto
Sent: Fri, Mar 8, 2019 8:14 pm
Subject: [ap-gto] Re: Motor Stall quick help needed



I was afraid it would be something like that.  I'll call tomorrow to get it fixed.

When the pier crash happened it was a (un)perfect storm of events that happened to cause the problem.  Several things didn't happen that should have happened, including an alert that would wake me when there's a problem.  I'm guessing this scenario would only happen 1/100,000 times and it's just my luck.

Could you explain a bit more what you mean by "Apparently the clutches were tight enough but not locked..."?  I tightened the clutches by hand as hard as I could.  Does that not "lock" the axes?  

joel



Bill Long
 

This is a perfect example why using APCC is the best thing to do for unattended imaging. It allows a second line of defense, in the event that the software you use for imaging fails. 

APCC never fails. I've imaged unattended with both APCC Standard and APCC Pro, for boat loads of hours. You can set the most basic of limits, and it will protect you. For mounts costing close to $10k fully fitted, I think a $500 one time insurance policy is worth it. AP apparently thinks so too, because they offer you a 30% discount when you buy the mount to begin with. 

Now add up the price of the mount, the scope, the camera, etc... Seems prudent to protect it even moreso. 


From: ap-gto@... on behalf of chris1011@... [ap-gto]
Sent: Friday, March 8, 2019 6:22 PM
To: ap-gto@...
Subject: Re: [ap-gto] Re: Motor Stall quick help needed
 
 


I tightened the clutches by hand as hard as I could.  Does that not "lock" the axes?  
The motors can still overcome a hand tight clutch.

You need APCC and build limits. Your best bet for unattended. The only other way is a simple hour timer which has a 110 volt plug and will turn off power at a preset time.

Tomorrow is Saturday and the office phones won't be answered. Send AP an e-mail and I'll get Christine on it. meanwhile remove the motor from the gearbox and send it in. Send the motor, internal wires and back panel all as one piece.

Roland


-----Original Message-----
From: buckeyestargazer@... [ap-gto]
To: ap-gto
Sent: Fri, Mar 8, 2019 8:14 pm
Subject: [ap-gto] Re: Motor Stall quick help needed



I was afraid it would be something like that.  I'll call tomorrow to get it fixed.

When the pier crash happened it was a (un)perfect storm of events that happened to cause the problem.  Several things didn't happen that should have happened, including an alert that would wake me when there's a problem.  I'm guessing this scenario would only happen 1/100,000 times and it's just my luck.

Could you explain a bit more what you mean by "Apparently the clutches were tight enough but not locked..."?  I tightened the clutches by hand as hard as I could.  Does that not "lock" the axes?  

joel



Joel Short
 

Thanks Roland.  I appreciate the quick replies! 
joel


Joe Zeglinski
 

Rolando,
 
    On the matter of your work on a future CP4 “over-current” limiter – would it be possible to use an appropriate in-line fuse in the CP4 power cable?
 
    For example, using the cigarette lighter plug, which has a fuse in it – would replacing it with a suitably lower amp rated fuse have prevented this situation, or would it trip too easily on power surges? Can you suggest a more suitable fuse rating?
 
    Of course, that would mean having to keep a lot of spare glass fuses on hand, for such emergencies. Hopefully those would be exceptional, if proper axis Limits are programed into one’s controllers.
 
Joe Z.
 


Roland Christen
 


On the matter of your work on a future CP4 “over-current” limiter – would it be possible to use an appropriate in-line fuse in the CP4 power cable?
Sure you can but it might not blow.

We tested an overcurrent system but ran into issues where the current exceeded the set limits during the start of a slew and sometimes gave false positives. We are working on ways to set the current limit so that it won't trip during short overloads but will trip when something like a pier crash happens. The current sensors are in the CP4, we just need to get the right software configuration and then we'll make it available.

Rolando


-----Original Message-----
From: 'Joseph Zeglinski' J.Zeglinski@... [ap-gto]
To: ap-gto
Sent: Fri, Mar 8, 2019 8:40 pm
Subject: Re: [ap-gto] Re: Motor Stall quick help needed



Rolando,
 
    On the matter of your work on a future CP4 “over-current” limiter – would it be possible to use an appropriate in-line fuse in the CP4 power cable?
 
    For example, using the cigarette lighter plug, which has a fuse in it – would replacing it with a suitably lower amp rated fuse have prevented this situation, or would it trip too easily on power surges? Can you suggest a more suitable fuse rating?
 
    Of course, that would mean having to keep a lot of spare glass fuses on hand, for such emergencies. Hopefully those would be exceptional, if proper axis Limits are programed into one’s controllers.
 
Joe Z.
 



mike.hambrick@...
 

We encounter similar situations with spikes and surges with the safety interlocks in the chemical process industry. I am not sure how sophisticated the CP4 controller program is (it seems to me to be pretty powerful), but the way we deal with those situations is to program a delay into the interlock so that the trip condition (high / low current, pressure, level, flow, temperature, etc) has to exist for a specific period of time before the interlock will trip and shut the system down. We typically use delay times anywhere from 10 seconds to 2 minutes. This depends on the reliability of the instrument reading and the severity of the consequences.