Motor type?

**AcWxRadar** · 05-14-2009 01:12 PM

Within any satellite motor available (SG-2100, DG-240/280/380 or Stab motors) what kind of a motor is actually driving the gear train? Is it a simple DC motor or is it a stepper motor or something other?

If the motor has to count pulses to position properly I would assume it to be a stepper type motor, but it could also be using an electronic encoder as well or maybe both. A stepper or a servo motor or a brushless motor would make the most sense to me.

Can anyone inform me what is correct here?

Thanks

RADAR

**Larry1** · 05-14-2009 05:09 PM

Take a look at this picture from the Sadoun site

http://www.sadoun.com/Sat/Products/P...G240%20005.jpg

http://www.sadoun.com/Sat/Products/S...s/DiSEqC17.jpg

looks like a simple DC motor with a hall efect transistor to count the rotations. Notice the capacitors are NOT polarized, as you just reverse the power connection to reverse the motor. (or so it appears... someone who has one apart can verify)

**AcWxRadar** · 05-14-2009 05:23 PM

Originally Posted by Larry1

Take a look at this picture from the Sadoun site

http://www.sadoun.com/Sat/Products/P...G240%20005.jpg

http://www.sadoun.com/Sat/Products/S...s/DiSEqC17.jpg

looks like a simple DC motor with a hall efect transistor to count the rotations. Notice the capacitors are NOT polarized, as you just reverse the power connection to reverse the motor. (or so it appears... someone who has one apart can verify)

Oh heck, that's pretty simplistic. I would have expected something a little more elaborate and I assumed that the hall effect switches were for overtravel sensors only. In the H-H motor pix, it appears that one Hall Effect switch is being used as the home or reference position locator.

That answers my question just fine, Thanks Larry!

Gordy

**Anole** · 05-14-2009 08:16 PM

The little dish movers use a couple of relays to reverse the power to the DC motor.
See first picture: two large black rectangular blocks in the lower left are the relays.
Second picture is typical sensor board (yes, two boards in these motors).
Think the black rectangular object beneath the black magnetic cylinder, is the hall effect sensor.

Here's some old propaganda from
STAB

, comparing and contrasting their sensors to the then-current competition.
I found it compelling, and bought a STAB HH-90 over the mish-mash of 2100's out there.
Turns out, it was a wise decision at the time.

edit: also, the motors on the traditional screw jack movers for BUDs, and for both the Birdview H-H and AJAK 180 H-H in my signature, are all DC motors with brushes, too

**AcWxRadar** · 05-15-2009 12:11 PM

Originally Posted by Anole

The little dish movers use a couple of relays to reverse the power to the DC motor.
See first picture: two large black rectangular blocks in the lower left are the relays.
Second picture is typical sensor board (yes, two boards in these motors).
Think the black rectangular object beneath the black magnetic cylinder, is the hall effect sensor.

Here's some old propaganda from
STAB

, comparing and contrasting their sensors to the then-current competition.
I found it compelling, and bought a STAB HH-90 over the mish-mash of 2100's out there.
Turns out, it was a wise decision at the time.

edit: also, the motors on the traditional screw jack movers for BUDs, and for both the Birdview H-H and AJAK 180 H-H in my signature, are all DC motors with brushes, too

Anole,

My brother has a few SG-2100 motors and one of them had one of those direction control relays stick closed. Whenever the motor was commanded to move (in either direction) it would only move in the one direction.

He tried to find a direct replacement relay, but was not successful. He did find one that would physically fit, but the pinout was incorrect, so he was going to have to modify the circuit to accommodate this.

He also found that the current spec's of the original relays were shy of what they should have been. Quite underrated. If anyone finds that their motor drives only one direction or won't drive either direction, these relays might be worth inspection if all other possibilities are exhausted.

During my career in Avionics, I was exposed to all sorts of miniature motors. Servo motors and mini brushless motors and steppers. I would have opted to use a servo motor of a similar type used in some of the flight instrumentation systems. Of course, you wouldn't want to use one that was approved for aircraft service as no one could ever afford the price. $800 to $2600 for just the motor itself! Yikes!

We had a joke in the repair field of Avionics...

If they can afford to Fly, they can afford to Buy! Ha ha.

RADAR

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