Re: [CAD_CAM_EDM_DRO] RE: Re: RE: Re: Mavilor Servos, how to test + Identify

John Harnedy wrote:

> > Thanks Jon for the quick reply.
> > Did some further examination
> > Nameplate says DC servo motor, amazing what one can find out when i open my eyes!!!
>
> Ahh, that helps.
>
> JH Took off the nameplate and here are the best guesses that we could make ( got the better half to assist as my eyes are suffering from 2 decades of long days and nights on CAD)
> Ncm = 22? or 27?
> V 7? could be a 0, 5 6, or 8
> RPM 3000
> KW 0.2 or 0.7
> Amps unable to read anything

Ugh. A nameplate that can't be read isn't much good!

>
> Unfortunately, there are lots of variations. Are the brushes all the same, and in
> the same plane?
> JH Just 4 at one end on same plane, with opposite ones connected together

OK, a 4-pole DC motor, standard connections.

> Many servo motors have temperature sensing devices (thermocouples, thermistors
> even thermostats) inside to warn the machine control of overheating. Some really
> oddball servos have windings that either boost or buck the permanent magnet
> field.
> JH Unable to find any thermal protection device
>
> Check the Green/Yellow wire to see if it is a case ground.
> JH yes it is

Good, now we have 3 wires pretty well identified.

> Check the resistance on the brown and blue wires, maybe that will indicate
> something. Inspect the interior of the motor with a flashlight and see if there is
> a cooling fan.
> JH no specific cooling fan, but the motor construction is " disc armature"printed" motor" with 8 poles.
>
> Put a voltmeter on the brown and blue wires and turn the motor.
> If you get a voltage, it may be a tach winding.
> JH yes got up to 8VDC peak on fastest hand turn i could achieve

Well, it seems brown and blue must be motor power, as they are heavier on the
larger motors. Could be about 15 V/1000 RPM, so a 45 V motor, give or take
about 50%. Hmmm, a disc armature motor. These aren't real powerful, and
need a lot of amps, normally, as they have VERY few turns of 'wire' on a
PC board.

It would be real useful to figure out the peak current rating, as if you exceed
that you will demagnetize the magnets, and the motor will be junk.

Jon