Re: [CAD_CAM_EDM_DRO] Servo Motor & Driver

Its a fairly large servo.
The total power output puts it outside most steppers range.
Industrial servo controls will be expensive (I've never used one, but
maybe 2000-4000$ for 3 motors + drivers).
Buying new industrial servo cards and motors is easy and expensive.

What do you want to do ?
Smaller steppers or servos will work easily and cheaply, but can you
live with smaller power output ?
I.e. it will be slower or less accurate or less powerful by maybe 20-40%
depending on the actual rpm range in use.
You can get steppers into that torque range - did the motor actually
only turn 400 rpm ?
If so, in that case steppers would work, and be easy/cheap.
About 400$ for geckos and about 600 $ for 3 steppers at maybe about
1200 oz-in.
Many people on the lists can sell you the motors, well proven and easy.

115 in-lb x 400 RPM / 63025 = 0.72 hp = (/ 1.341 to kW) = 0.54 kW or 540
Watts.
Steppers stop at about 300 watts see the geckomotion.com whitepaper and
explantions for details.

What will be the use for the mill ?
If its not industrial production, I would go for geckos + smaller servos
(or steppers if hobby or home shop).
Maybe 1400 $ in total. Only you can say if its worth it.

Best of luck ;)



weedytan wrote:

> 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
>
>