RE: [CAD_CAM_EDM_DRO] Servo Motor & Driver

If the motors and servo drives are good, try to find out some more details
of the servo cards.

They will probably be analogue 0 to 5V, 0 to 10V or +/- 10V signal input.
They will also probably run in velocity mode.

If you can set them to toque mode, then you could use a pixie card to drive
them, simple parallel port IO card and it will run off mach3.



Personally I would keep with the big servo's, and avoid steppers.
Many people work OK with steppers but really they are not ideal for many
reasons in this application, though some of the problems can be overcome.

As to servo's your's are that big you are not easily going to find a
step/direction drive card, there presently aren't any 350V servo cards in
the hobby scene, but you could drop the voltage and use them at half speed,
there are a couple of possibilities here, amongst four viable cards, two are
definitely not viable, one has questions one is too new to know at present.
If your motors and cards work keep them, to replace with something as good
is really going to eat cash.

If the servo cards are faulty, try looking at Granite Devices new cards, and
dropping the servo voltage, these might be viable. With the voltage bit,
keeping things simple, the voltage is proportional to the motors maximum
speed, the current proportional to it's torque.



If you want to go the EMC way, then Jon Elson has some viable cards he may
be able to setup to meet your needs.



Dr. Mark Vaughan Ph'D. B.Eng. M0VAU

Managing Director

Vaughan Industries Ltd, reg in UK no 2561068

Water Care Technology Ltd, reg in UK no 4129351

Addr Unit3, Sydney House, Blackwater, Truro, Cornwall, TR4 8HH, UK.
Phone/Fax 44 1872 561288

RSGB DRM111(Cornwall)

_____

From: CAD_CAM_EDM_DRO@yahoogroups.com
[mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of weedytan
Sent: 15 June 2007 16:55
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] Servo Motor & Driver



Hi all,

I was asked by a friend to look at a Taiwan made ACRA Vertical NC Mill
(year 1996 or 1997) today wherein the controller is dead and to find
out the feasibility of converting it to a CNC using Mach3 or EMC. Here
are some details:

1) The servo motor has a name plate that says: Special VR Motor made
by Servo Products Co., Pasadena; Voltage - 350VDC; Torque - 115 in-lb
(continuous); Current - 6 amp/phase; 3 phase; 3.2 Ohms/phase; 400 RPM
2) The servo driver board says ZD-6363 Rev I.
3) This is a 3-axis NC mill with 3 HP Induction Motor for the spindle
controlled by a VFD.
4) It wasn't in use for about 2 years and it boot up Windows 98. After
which, it will not go into the software controller.

Since I am more used to Stepper Motors/Drivers, and totally ignorant
of Servo Motors, may I ask for some assistance for the following:

1) How can I test without going thru the controller if the servo
motors and/or servo drivers are still alive?
2) If the servo drivers are dead (most likely, as someone previously
worked on it and gave up), what alternative servo driver can I use?
3) Is it advisable to use stepper motors/drivers to replace the servo
motors/drivers in the same holding torque range? If not, and if I need
to replace the servo motors as well, what newer model of servo motors
and drivers can I use? Take note that the servo motor has a continuous
torque of 115 in-lb (about 13 Nm or 1,840 oz-in).

TIA for whatever info you can provide.

WT





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