Topics

Mach2 power consumption #Mach2GTO

 

I'm wondering what other Mach2 users are experiencing with power usage with their mounts.  

Using a Powerwerx watt meter, I'm seeing about 1.05 amps at 13.8V while tracking, as much as 5.15 amps while slewing.  I'm powering with a Pyramid PS-15KX supply, and it gets hot.  (Still indoors due to lousy weather).

These motors are drawing a lot of juice!  Is that to be expected?

Jerome

Dean Jacobsen
 

I will check for you tomorrow night if you haven’t gotten an answer by then Jerome.
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 

Christopher Erickson
 

Steppers always require more power/amps than servos.

Amps times volts equals watts.

Watts of electricity consumed converts 1:1 to watts of heat generated.

A typical AC-DC power supply is about 80-95% efficient, depending on design. That means another 5-20% of power consumption and heat generation.

Make sure your observatory and/or imaging setup is configured to minimize any impact these various heat sources will have on your local seeing.

Thermodynamics 101.

-Christopher Erickson
Observatory engineer
Waikoloa, HI 96738
www.summitkinetics.com
   


On Mon, May 25, 2020, 10:03 AM Jerome Allison <jallison@...> wrote:
I'm wondering what other Mach2 users are experiencing with power usage with their mounts.  

Using a Powerwerx watt meter, I'm seeing about 1.05 amps at 13.8V while tracking, as much as 5.15 amps while slewing.  I'm powering with a Pyramid PS-15KX supply, and it gets hot.  (Still indoors due to lousy weather).

These motors are drawing a lot of juice!  Is that to be expected?

Jerome

 

Thanks, Christopher.  I kind of forgot about stepper motors and their holding/stepping power requirements.  I made an Arduino based stepper focuser system a couple years ago and programmed it to sleep after twenty seconds, just so it wouldn't use a lot of power for hours on end. :)  
Jerome

Christopher Erickson
 

Microstepping means that the steppers must always be under power. Full steps can sometimes mean you can put the motor to sleep. Especially when using worm drives off of the stepper.


On Mon, May 25, 2020 at 5:02 PM Jerome Allison <jallison@...> wrote:
Thanks, Christopher.  I kind of forgot about stepper motors and their holding/stepping power requirements.  I made an Arduino based stepper focuser system a couple years ago and programmed it to sleep after twenty seconds, just so it wouldn't use a lot of power for hours on end. :)  
Jerome

Terri Zittritsch
 

On Mon, May 25, 2020 at 04:02 PM, Jerome Allison wrote:
I'm wondering what other Mach2 users are experiencing with power usage with their mounts.  

Using a Powerwerx watt meter, I'm seeing about 1.05 amps at 13.8V while tracking, as much as 5.15 amps while slewing.  I'm powering with a Pyramid PS-15KX supply, and it gets hot.  (Still indoors due to lousy weather).

These motors are drawing a lot of juice!  Is that to be expected?
I checked out mine early on as well, and found that its current draw higher than the specs, at 12V, but was dealing with other things so haven't fed back the numbers.   I haven't paid a lot of attention to the 18V current numbers, which should be lower, because while it's plugged in I have all the juice that I need.   

Terri


uncarollo2 <chris1011@aol.com>
 

Yes, that is correct. The mount powers both microsteppers with full current at all times. The Dec motor must be powered even when it is not turning in order to maintain an exact microstep positions. This is fundamental to microstep motors. Slewing both motors at 1800x draws the most power - the motors are beefy and rated at 2.7 amps each.

The motors can be powered at a lower level, but then you may run into stalls and/or resonance situations. If this is something that you would like a handle on, we can incorporate that into our next keypad feature list. However, care must be taken to carefully balance the load so that the motors will work within their lowered load capability at the lower current levels. We can never achieve the low current consumption of our earlier DC servo motors because they have very much higher efficiency than a stepper motor. Also the Dec motor on a DC servo doesn't draw any current when it is sitting still, whereas a microstepper must draw full current whether it is moving or not in order to maintain sub-arcsec positions.

Rolando



-----Original Message-----
From: Jerome Allison <jallison@...>
To: main@ap-gto.groups.io
Sent: Mon, May 25, 2020 3:02 pm
Subject: [ap-gto] Mach2 power consumption #Mach2GTO

I'm wondering what other Mach2 users are experiencing with power usage with their mounts.  

Using a Powerwerx watt meter, I'm seeing about 1.05 amps at 13.8V while tracking, as much as 5.15 amps while slewing.  I'm powering with a Pyramid PS-15KX supply, and it gets hot.  (Still indoors due to lousy weather).

These motors are drawing a lot of juice!  Is that to be expected?

Jerome

uncarollo2 <chris1011@aol.com>
 

How come you are not using the 24 volt power supply that comes with the mount? It is much more efficient than your Pyramid.

Rolando



-----Original Message-----
From: Jerome Allison <jallison@...>
To: main@ap-gto.groups.io
Sent: Mon, May 25, 2020 3:02 pm
Subject: [ap-gto] Mach2 power consumption #Mach2GTO

I'm wondering what other Mach2 users are experiencing with power usage with their mounts.  

Using a Powerwerx watt meter, I'm seeing about 1.05 amps at 13.8V while tracking, as much as 5.15 amps while slewing.  I'm powering with a Pyramid PS-15KX supply, and it gets hot.  (Still indoors due to lousy weather).

These motors are drawing a lot of juice!  Is that to be expected?

Jerome

Dean Jacobsen
 

Ok, now that raises a question for me.

While we do have 120V power at the observatory, it is unreliable [rural location, the utility sometimes shuts it off to prevent brush fires, a club member may not realize that I am on site and will shut down the sit power when they leave at 2am].  So, I have everything set up to run on 12v and if the power is interrupted, then everything immediately switches over to a 12v LiPO4 battery that is on standby [ http://www.westmountainradio.com/product_info.php?products_id=epic-pwrgate ].

It looks like I should be using a 12v to 120v inverter for the mount with the supplied 24v power supply plugged in... right?
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 

uncarollo2 <chris1011@aol.com>
 

No need for the inverter unless you want to run the mount at 24 volts. Using an inverter wastes power, better to run at 12 volts directly. The mount is most efficient at 12 volts. Without the keypad plugged in it consumes about 14 watts at 12v, 15 watts at 18 volts and 16.6 watts at 24 volts. It is limited to 1200x slewing at 12 volts and 1800x above 18 volts.

Rolando



-----Original Message-----
From: Dean Jacobsen <deanjacobsen@...>
To: main@ap-gto.groups.io
Sent: Tue, May 26, 2020 11:20 am
Subject: Re: [ap-gto] Mach2 power consumption #Mach2GTO

Ok, now that raises a question for me.

While we do have 120V power at the observatory, it is unreliable [rural location, the utility sometimes shuts it off to prevent brush fires, a club member may not realize that I am on site and will shut down the sit power when they leave at 2am].  So, I have everything set up to run on 12v and if the power is interrupted, then everything immediately switches over to a 12v LiPO4 battery that is on standby [ http://www.westmountainradio.com/product_info.php?products_id=epic-pwrgate ].

It looks like I should be using a 12v to 120v inverter for the mount with the supplied 24v power supply plugged in... right?
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 

Dean Jacobsen
 

Thanks Roland.

the part in your previous post about "stalls and/or resonance situations" got me thinking that I should run the mount at 24 volts instead of the 13.6 volts that I have the power supply set to.  Power efficiency is not really a concern while the mains are on and the standby battery is a large capacity battery which would actually run my AP900, camera, laptop, etc. for two nights.  So I can afford to be inefficient with an inverter if it means that I am avoiding the possibility of stalls and/or resonance situations.

--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 

uncarollo2 <chris1011@aol.com>
 

The mount will not stall at 12 volts. It has the same capability as it has at 24 volts. except it won't slew as fast.

Rolando



-----Original Message-----
From: Dean Jacobsen <deanjacobsen@...>
To: main@ap-gto.groups.io
Sent: Tue, May 26, 2020 1:41 pm
Subject: Re: [ap-gto] Mach2 power consumption #Mach2GTO

Thanks Roland.

the part in your previous post about "stalls and/or resonance situations" got me thinking that I should run the mount at 24 volts instead of the 13.6 volts that I have the power supply set to.  Power efficiency is not really a concern while the mains are on and the standby battery is a large capacity battery which would actually run my AP900, camera, laptop, etc. for two nights.  So I can afford to be inefficient with an inverter if it means that I am avoiding the possibility of stalls and/or resonance situations.

--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 

Dean Jacobsen
 

Excellent.  I will just keep doing what I have been doing then.  Slews at 600x have always been good enough for me.
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 

 

All my other equipment is based on 12V power.  I use the Pyramid indoors for testing/practice, or in the back yard.  Otherwise when at a dark site, it's all 12V batteries.  But, I'll give it a try.

Thanks for reminding me about microstepping.  With the Arduino focuser I mentioned before, I intentionally used a stepper with a 28:1 planetary gear reduction.  That way I could avoid microstepping and thus put it to sleep without losing its position.  With that gearing, it's very resistant to external movement. 

Jerome

 

Roland, do you have a better 120VAC to 12VDC power supply solution for me?  I'm looking for one.
Between weather and schedule, I finally had a chance outside in the back yard Friday night to see how everything would work.  I've made a lot of changes to my equipment arrangement and wanted a dry run.
I don't want to draw this out, but that Pyramid power supply that I mentioned before (and you noted its inefficiency) does seem to be pretty lame.  I only bought it because it seemed pretty popular/well regarded a few years ago. After a couple hours running my mount, cameras, etc., it was fine.  (as in, who's worrying about the power supply going out?)
But later, during a big double axis slew it QUIT with a "Protection" error light. I let it cool down and it worked from then on, but I was much gentler with it.
I don't want this to happen again, so is the Powerwerx supply the best solution?
Thanks, Jerome

David
 

Try one of these.  I have them both and they are great solutions using Powerpole connections.
They run cool, and quiet, and have never given a problem in the years I’ve used them.



David




On Jun 20, 2020, at 6:27 AM, Jerome Allison <jallison@...> wrote:

Roland, do you have a better 120VAC to 12VDC power supply solution for me?  I'm looking for one.
Between weather and schedule, I finally had a chance outside in the back yard Friday night to see how everything would work.  I've made a lot of changes to my equipment arrangement and wanted a dry run.
I don't want to draw this out, but that Pyramid power supply that I mentioned before (and you noted its inefficiency) does seem to be pretty lame.  I only bought it because it seemed pretty popular/well regarded a few years ago. After a couple hours running my mount, cameras, etc., it was fine.  (as in, who's worrying about the power supply going out?)
But later, during a big double axis slew it QUIT with a "Protection" error light. I let it cool down and it worked from then on, but I was much gentler with it.
I don't want this to happen again, so is the Powerwerx supply the best solution?
Thanks, Jerome

uncarollo2 <chris1011@aol.com>
 

Powerwerks is a great product. Very robust and highly efficient.
For your Mach2 I recommend that you use the 24 volt power supply that comes with the mount. Run just the mount with that and use a separate supply for everything else.

Rolando



-----Original Message-----
From: Jerome Allison <jallison@...>
To: main@ap-gto.groups.io
Sent: Sat, Jun 20, 2020 5:27 am
Subject: Re: [ap-gto] Mach2 power consumption #Mach2GTO

Roland, do you have a better 120VAC to 12VDC power supply solution for me?  I'm looking for one.
Between weather and schedule, I finally had a chance outside in the back yard Friday night to see how everything would work.  I've made a lot of changes to my equipment arrangement and wanted a dry run.
I don't want to draw this out, but that Pyramid power supply that I mentioned before (and you noted its inefficiency) does seem to be pretty lame.  I only bought it because it seemed pretty popular/well regarded a few years ago. After a couple hours running my mount, cameras, etc., it was fine.  (as in, who's worrying about the power supply going out?)
But later, during a big double axis slew it QUIT with a "Protection" error light. I let it cool down and it worked from then on, but I was much gentler with it.
I don't want this to happen again, so is the Powerwerx supply the best solution?
Thanks, Jerome

 
Edited

Thanks, David and Rolando.
I will get the simpler Powerwerx supply when it's back in stock, and use the 24 volt supply for the mount in the meantime. 
Jerome
P.S. The mount worked perfectly - I really love it, Roland. Great stuff.

Christopher Erickson
 

And MAKE SURE that you use a different style of connectors for the 24V power supply and 12V supply. You don't want to connect 24V to your precious camera or other 12V devices.

Anderson makes powerpole connectors in different sizes, for example. Prevent mixups.


-Christopher Erickson
Observatory engineer
Waikoloa, HI 96738
www.summitkinetics.com
   


On Sat, Jun 20, 2020, 7:01 AM Jerome Allison <jallison@...> wrote:

[Edited Message Follows]

Thanks, David and Rolando.
I will get the simpler Powerwerx supply when it's back in stock, and use the 24 volt supply for the mount in the meantime. 
Jerome
P.S. The mount worked perfectly - I really love it, Roland. Great stuff.

uncarollo2 <chris1011@aol.com>
 

The Mach2 power supply does not use Anderson power poles. It uses Hirose connectors. This 24 volt supply should never be used to power anything else, no matter how tempting. It is ONLY to be used to power the Mach2, nothing else.

Roland


-----Original Message-----
From: Christopher Erickson <christopher.k.erickson@...>
To: main@ap-gto.groups.io
Sent: Sat, Jun 20, 2020 4:26 pm
Subject: Re: [ap-gto] Mach2 power consumption #Mach2GTO

And MAKE SURE that you use a different style of connectors for the 24V power supply and 12V supply. You don't want to connect 24V to your precious camera or other 12V devices.

Anderson makes powerpole connectors in different sizes, for example. Prevent mixups.


-Christopher Erickson
Observatory engineer
Waikoloa, HI 96738
www.summitkinetics.com
   

On Sat, Jun 20, 2020, 7:01 AM Jerome Allison <jallison@...> wrote:
[Edited Message Follows]
Thanks, David and Rolando.
I will get the simpler Powerwerx supply when it's back in stock, and use the 24 volt supply for the mount in the meantime. 
Jerome
P.S. The mount worked perfectly - I really love it, Roland. Great stuff.