Planning Retrofit, lots of questions re: VSD-XE

[snoman70]

Just ordered a VSD-XE from Blurry to play with, we'll see where we go from here.

Here are my questions...

1) Using a CUI AMT-102 encoder, what cable should I use? The distance from encoder to control will be between 10 and 20 feet. (ie, can I use the 1 foot cable spliced with a shielded wire, or should I use the line driver cable and splice it to shielded wire).

2) Per previous post:

Originally Posted by Xerxes Check out also CUI AMT102 from digikey. It's robust and low cost, but it's not optical and may have lower dynamic performance (longer response time to sudden rotation). For most users it's still perfectly Ok.

I am mounting these on servo motors that will be going on a small vertical machining center (Brother TC-211 drilling/tapping machine). Previous motors were 100watt in xy and 200 watt in z Toshiba servo motors that were way too small per the service tech that I spoke with. I will either reuse current motors for time being, or replace with Keling DC servo motors.

In realistic use situations, when would one expect to see performance issues with the encoders? Just rapid accels? I don't need them...can I limit them in drive tuning?

3) Realistically, I believe I can use the current three phase servo motors, OR I can order new Keling KL34-180-90 motors and mount them to the machine. Am I correct in my understanding that I can use two of these Keling servo motors per drive? If so, I would be buying three motors and two drives, whereas if not, I would be ordering three drives and no motors....sort of a wash as far as cost is concerned. I'd almost rather have the new motors.

4) Power supply for the Keling KL34-180-90..... 90 V, 7.8 A continuous, 40 A Peak (limited to 20 by drive). Planning for four of these motors, what would be a reasonable size power supply? My maximum RPM is going to be around 1000, and that's for 3 seconds MAX. I would never have more than 2 axes moving at once, and even then, I'm not going to put these motors to full use because the mill spindle won't handle it!

5) Finally, Can I use a 140 DC Volt power supply with the 90 volt motors?

Sorry for all of the questions, I'm new to servo motors.

[Xerxes]

1) Differential cable is the best. Digikey sells differential line driver cables for that encoder.

2) In practice the difference may be seen as reduced stiffness of motor, but no big difference. I haven't heard anyone complain about the results with CUI 102.

3) Yes, if you have brush DC motors, then VSD can be used in DualDC mode to drive 2 axis per one drive.

4) BTW, in single axis mode VSD-E/XE can also drive 40A peak. If you need only 1000 rpm tops, then you don't need more than 50VDC supply. I believe 500W would be enough but its good to have a backup plan of adding power if necessary.

5) It probably won't hurt the motor, but may add more stress to brushes.

[asuratman]

Xerxes,
On VSD EX dual DC, I just want to make sure I got motor from kelling KL34-180-90 with Green is Ground, Red is +, Black is Common. I made the green is connected to Ground of VSDE, the red is connected to 80 VDC of VSDEX and Black is connected to FG of VSD EX, is this OK? Sometimes, I got my router shaking when start up. Do I need to connect the body of transformer to FG of VSDEX. I used 2 transformer paralel just to make sure enough power. Thanks.

[snoman70]

Great...thanks!

I've actually got a 48VDC power supply out of an old bridgeport that is huge, I'll just plan on using that. In this case I have multiple machines that I will probably power off the one power supply, just trying to decide how to do the lathe.

[asuratman]

sowman70,
Post your build here till finish so we can share electronic knowhow.

[Xerxes]

Originally Posted by asuratman Xerxes, On VSD EX dual DC, I just want to make sure I got motor from kelling KL34-180-90 with Green is Ground, Red is +, Black is Common. I made the green is connected to Ground of VSDE, the red is connected to 80 VDC of VSDEX and Black is connected to FG of VSD EX, is this OK? Sometimes, I got my router shaking when start up. Do I need to connect the body of transformer to FG of VSDEX. I used 2 transformer paralel just to make sure enough power. Thanks.

In my KL34-180-90 motor armature is connected to black & red wires. So these should go to drive outputs (MOTOR connector). Green can be connectedo to FG.

[snoman70]

Shouldn't you be able to measure the resistance of the motor winding?

In your general opinion, are the KL34-180's overkill for a small vertical machining center? Think CNC bridgeport with linear rails and ballscrews. Honestly a little lighter.

Is there a danger of powering with too much motor?

[asuratman]

It is better to use that size of motor KL34-180-90 for the size ur mill, its not overkill, it depend what kind of material will be machined. With that motor you may machine steel. There is no danger to have big motor. I prefer to have big motor, I can play with it.