> A quick question for those in the know. Im wiring the Mac Trim serve
>that is on my elevator to my Infinity control stick and have a bit of a
>question...!! The servo has 5 wires comming out of it: 2 control the
>forward/backward (up/down) movement of the trim servo screw..these are both
>white in color. The other 3, Blue/Green/and Orange connect into the
position
>indicator to indicate servo movement. The control stick that I am using
has
>3 wires (from the coolie hat control) that control pitch trim. The middle
>wire (and center postion on the switch) is a ground (black wire) The other
>two wires are Brown and Solid Blue and control up down movement. My
question
>is how does the servo get 12V power? I have wired everything per the plans
>of both the Mac servo and the control grip. I have checked the switches and
>wires with a volt/ohm meter and connections are good. The serve motor moves
>when directly attached to the battery. The only 12V input to the system is
>the Red/white stripped wire comming from the position indicator (light).
>Obviously I am missing something in the wiring setup or some additional part
>is required. I know it doesnt work because it isn't getting any 12V
>power.....just wondering how it is supposed to get that power or if maybe
the
>control stick is not compatible with the MAC servo. As always thanks ahead
>of time for your responses. Take care and happy building/flying!!!
MAC uses a permanent magnet motor where direction of rotation is determined
by polarity of the applied voltage . . . I've complained to MAC folks
at OSH booth many times about the two WHITE wires . . . they could be
different colors where on color is (+) extend and (+) retract . . . I
could put out ACCURATE wiring diagrams for their product. Two white wires
just doesn't cut . . .
Gunching aside, the trim swich in an Infinity grip will not directly
interface with a MAC servo. MAC sells a "relay deck" for this purpose.
You can also use a two pole, double throw, center off (on)-off-(on) rocker
switch to directly drive the servo's PM motor. The wiring with a
relay deck is shown at . . .
http://www.aeroelectric.com/articles/trim.pdf
If you want to build your own relay deck, two small relays
wired as shown in . . .
http://www.aeroelectric.com/articles/trim2.pdf
will do the trick.
Bob . . .
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( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
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http://www.aeroelectric.com
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