Re: [CAD_CAM_EDM_DRO] Servo Motor & Driver

Hi Hannu,

Thanks for the advise. That NC mill is in use, as far as I can tell, for making moulds.

I'll talk to my friend and see what he has in mind and offer him various options.

Best regards,
WT

----- Original Message ----
From: hannu <hvenermo@...>
To: CAD_CAM_EDM_DRO@yahoogroups.com
Sent: Saturday, June 16, 2007 1:07:40 AM
Subject: 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

>

>

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