EGIS motor

[dreambox1959]

I have just made the first tests of the egis .
the AZ motor at no load consumes 0.5A but is very noisy on 180° then it calms down ???
the EL motor at no load consumes 0.3A and works well
I'm going to check if there is a mechanical problem on the AZ engine, it seems to slow down when the noise appears.

 

[Channel Hopper]

The grease may have dried out.

 

[dreambox1959]

issue was in the motor .
before:

after:

inside motor

 

[Trust]

Great job , sounds like new !

 

[dreambox1959]

I am currently doing tests on the egis EPR103 I was surprised at the flow of the pulses.
there is a double sensor on the axis of the motor (on the actuators the reed sensor is on the endless screw after the gear ratio) there is a pulse every 700µs instead of 14ms to 24ms for actuators.
when the power supply to the motor is cut off, we still receive 10 pulses!!!
I therefore pass the pulse signal through a divider by 4 (it also does filtering) and I arrive at correct operation.
to keep all the pulses would require a much more powerful microprocessor and we would have 200 pulses per degree, which would be really exaggerated!!!!

 

[Channel Hopper]

I am currently doing tests on the egis EPR103 I was surprised at the flow of the pulses.
there is a double sensor on the axis of the motor (on the actuators the reed sensor is on the endless screw after the gear ratio) there is a pulse every 700µs instead of 14ms to 24ms for actuators.
when the power supply to the motor is cut off, we still receive 10 pulses!!!
I therefore pass the pulse signal through a divider by 4 (it also does filtering) and I arrive at correct operation.
to keep all the pulses would require a much more powerful microprocessor and we would have 200 pulses per degree, which would be really exaggerated!!!!

Are the relays wired so that any back EMF from motor movement is shorted out ?

 

[Trust]

I dont have the schematics with me (vacantion) but I know there are in the EPS-103 controller PRG nr's within it is possible to stop within a adjustable amount of pulses .
see pages 27 - 30 from

http://antena.fe.uni-lj.si/literatura/Razno/Diplome/Radioteleskop/antena/Handbook%20CL%20Sat%20desk%20engl%203-4.pdf

Egis rotor is made for large dishes and antennas , to stop the rotor at once could damage the outdoor equipment .

 

[dreambox1959]

i use my positioner adapted to an egis motor
start and stop are soft (i use PWM power supply for all motors)
motors inside egis works when duty cycle is about 40% to 100% , with 40% it run slowly but not enought to stop on the right value .
on classic actuators it s works well !!
today i ll test to stop power a few pulse before it reach the good value .

"Are the relays wired so that any back EMF from motor movement is shorted out ?"
yes when the power is off, the motor pins are shorted

 

[dreambox1959]

good infos trust !
the man (or woman) who created the original firmware saw what i see today !!
they used some tricks :

 

[Channel Hopper]

Yes, slow start / stop is a feature on a number of advanced designs, sometimes with three steps for gate positioner designs where the voltage to the actuators is controlled, either with timer or sensor.

 

[Trust]

For a (very) short moment the idea crosssed my mind to use this Egis in H2H mode with fixed dish elevation (exept for inclined) with the 1.8 Channelmaster included lnb revolver attached to a heavy skewmotor between dish and Egis dish adapter . Give me the possibility to skew all lnb's .
One of my first setups was a Egis with a 1.5 M PrimeFocus with such skew system .

 

[dreambox1959]

I thought of that too.
by mounting the egis engine at a 45° angle (my latitude) .
I would need a piece between the original dish mount and the dish to compensate for this 45°.
and of course the whole thing should be able to face south.
It would make a great H to H.
probably a bit expensive and bulky ???

 

[dreambox1959]

Yes, slow start / stop is a feature on a number of advanced designs, sometimes with three steps for gate positioner designs where the voltage to the actuators is controlled, either with timer or sensor.

I calculate the value of a PWM with the delta between the actual position and the destination for the final 127 pulses before reaching the final destination.
For the start, I create a value of a PWM that grows with time for 127 pulses
between these two values the motor run free .

 

[dreambox1959]

a release with offset am+ and am-
position is reach either from east or west

 

[Channel Hopper]

I calculate the value of a PWM with the delta between the actual position and the destination for the final 127 pulses before reaching the final destination.
For the start, I create a value of a PWM that grows with time for 127 pulses
between these two values the motor run free.

Do you believe you would damage the outdoor equipment by rewiring the relays to short the back EMF ?

 

[suedschwede]

Do you believe you would damage the outdoor equipment by rewiring the relays to short the back EMF ?

EGIS motor #28

 

[Channel Hopper]

EGIS motor #28

Then there is a fault in the wiring, possibly a relay contact is not functional.

 

[dreambox1959]

i dont think so !
encoder is on motor , it turns very quickly , it takes 100ms to really stop
now i m using these parameters (like egis controler) and it is ok .
i use now a 89lp51 (12 time faster than 89s52) and i can drive pulses carrefully.

 

[Channel Hopper]

What happens if you drop the voltage to half value ?

 

[dreambox1959]

What happens if you drop the voltage to half value ?

the motor run to half speed !!!!
pulse is 2.5 ms long instead of 1.2ms .
i put a at89lp51 in place of 89s52 an now i manage pulse from encoder at real speed (pulse every 1.2ms).
i have adapted firmware to show 5 digits number (1 to 65535) .
on AZ turn i receive about 50000 pulses (for 180°) on EL movement it is 30000 pulses!!!!!!