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View Full Version : PC controller for 3 phase AC 115V 400Hz Servo Motors?



Piggles
01-01-2013, 11:36 PM
Happy New Year everyone!

I have a roller blind presentation artificial horizon from an EE Lightning. It wasn't long before I started to to take it apart and see what was going on inside.

At this stage I've removed (and stored) all the original solid state circuitry, The plan (at the moment) is to use the original servos and lighting of the unit. Several reasons, I don't want to replace all the servo motors, some are in very tight spaces then there is the consideration of the torque involved to move some fairly involved mechanical drives in the instrument. There is also a certain neatness to this option, all the original circuit boards unplugged from what looked a lot like standard LPT/Parallel port style connectors, this leaves me with all the wiring and the servos in place to drive the instrument.

So I am hoping to find a suitable PC compatible encoder or board. The unit also contains a Synchros unit, this I assume is for returning the position of the roll indicator (the whole assembly of the roller blind rotates to indicate roll). It would be nice to somehow make use of that too.

So where do I start? I've been searching the web for information, some of the theory is beginning to sink in, at this stage an off the shelf plug and play solution would have a lot of appeal, but I'm not sure if there is one available for 3 phase 115v 400Hz servo motors?

I will need to be able to control a good number of them too, there are several of these servo motors in this instrument, and plenty more to come as the project progresses. So any thoughts on what I should take a look at? I'm looking to run the instruments from FSX.

Piggles
01-06-2013, 07:27 AM
Well a self reply, I guess 118 views so far and no response points to no effective off the shelf solution available.

I did find one unit, meant for actual aircraft applications. I didn't inquire about the price as it looked extremely bulky for driving a single servo motor. In fact far bulkier than the original electronics from the 1960s.

Plan B is in action, I have the lighting circuit of the instrument tested and lighting up (nice feeling when something that may well have not operated in over 30 years works perfectly) and also found the correct DC voltage to trigger the electromagnetic power on indicator. Basically it is a coil that causes a spring loaded circular metal disc to move over a warning light when the unit is receiving power and a valid MRG signal.

I'm now researching possibly using the original electronics to drive the motors, also possibly making my own circuit boards - I may well end up trying both routes and see which works out for the best. As there seems to be many pros and cons to each approach and with several instruments to tackle it would be good to see the problems and solutions each route presents.

I'll post up some pictures of the inner working of the instrument soon if people want to see them?

Brodhaq
06-18-2013, 05:15 PM
Hello,
how is your instrument going? Any updates? I wonder if it will work for you as I will face similar problems soon... How do the original servos look inside? Maybe you could partially open them and connect only their motors directly to PCB from nowadays standard servo which can be easily driven by OC card, hm? I am not sure if the 115V/400Hz is needed because of the controlling electronics or also for driving the motor. It would be great to do some reverse engineering and determine what are the operational requirements of those old servo motors...

Pavel

Albert Stephen
11-22-2013, 11:09 PM
The unit also contains a Synchros unit, this I assume is for returning the position of the roll indicator (the whole assembly of the roller blind rotates to indicate roll). It would be nice to somehow make use of that too.