On 2017-05-21, Martin E wrote:
On 5/20/2017 6:25 PM, DoN. Nichols wrote:
On 2017-05-20, Ignoramus31415 wrote:
On 2017-05-20, Jon Elson wrote:
Ignoramus31415 wrote:

My mill had DC motors and everything worked really nicely.

All three axes work.

Except for one thing. For 4th axis, I have a rotary table made by
Troyke with a resolver (not encoder). I bought from you a "resolver to
encoder signal converter".

Hmm ... I've only seen resolvers in aircraft instruments. Those
require 400 Hz power (26V IIRC). Is what you have also 400 Hz, or do
they make 60 Hz resolvers, too?

If they are 400 Hz, could some subsystem which is supposed to
generate the 400 Hz failing?

Good Luck,
DoN.

I want to say if you have a slave pair - one is a encoder and the other
a resolver. in other words - transmit and receiver.

One on a knob that is rotary or on a rack - and the other on a surface
that is moving. Sometimes in reverse the surface 'tells' the pointer
where to point.

Hmm ... that sounds more like synchros (AKA "selsyn"). An ac
signal applied to the rotor, and three phases (Wye connection) of
output. Thus the synchros had five leads, two for the rotor, and three
for the Wye connection of the stator.

Apply power to both rotors, and one will move to track the
other. Instead, take the second rotor, connect it to the input of a
servo amplifier, and the servo will rotate the one to which it is
connected until at 90 degrees, at which there is zero output, and a
slight motion will provide signal either at 0 degrees phase or at 180
degrees phase, causing the motor to rotate the servo until the output is
zero again. (This allows driving things which are heavier than the
synchro is capable of driving directly.)

A resolver, however, has one rotor signal with two stators at 90
degrees, and isolated from each other electrically. This produces
output signals on the two stators as a sine and a cosine of the rotor's
angle. (Some resolvers have two rotors at 90 degrees, so they can
process the output of a normal resolver with only one rotor winding, so
you can add two angles. (The resolvers which I am describing are quite
small, to fid in aircraft instruments.) I don't know whether there are
larger 60 Hz resolvers as there are larger 60 Hz synchros (the 60 Hz
ones were commonly used on shipboard, where the extra weight of the 60
Hz versions was not a significant penalty. They were the ones called
"Selsyn"s. And while all 400 Hz synchros which I have seen are all
pretty much the same, the receivers on the 60 Hz ones had an inertial
damper on the shaft, while the transmitters did not)

The resolvers have either six leads (two for the rotor, four for
the two independent windings) or eight leads (two for each winding in
the rotor, and two for each winding in the stator.

So -- I would really expect the Troyke rotating table to have a
synchro and a servo amp, but it could be a resolver, and some way to
connect that to a servo motor and amplifier.

Enjoy,
DoN.

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