Dynomotion

Group: DynoMotion Message: 589 From: Marty Escarcega Date: 8/15/2010
Subject: Kflop and Gecko 320X servo Amps

Tom, please don’t take offense! J

 

The servo specs I bought for my Clausing 12x24” CNC Lathe retrofit (using 2 motors on both axis, with Renco 1000 line encoders)

Electro Craft DC Brush Servos 0644-06-011

Continuous Stall Torque 192 oz-in

Peak Torque 960 oz-in

Maximum terminal voltage 60V

Maximum operating speed 1850rpm

Maximum pulse/peak current 22a

 

If the motor says peak current of 22A, what would be the nominal operating current be ?

Has anyone used the Gecko G320X with the Kflop motion controller, I’m still considering Snap amp. In fact I think Snap has slightly higher current rating than the 320x.

 

Thanks in advance

Marty

 

 

 

 

 
Group: DynoMotion Message: 597 From: carlcnc Date: 8/21/2010
Subject: Re: Kflop and Gecko 320X servo Amps
Marty
sell the 320's and go with the snapamp.
you will benefit from easier tuning,tech support
and gain a bunch of IO,
you won't regret it.
Carl

--- In DynoMotion@yahoogroups.com, "Marty Escarcega" <escarcega@...> wrote:
>
> Tom, please don't take offense! J
>
>
>
> The servo specs I bought for my Clausing 12x24" CNC Lathe retrofit (using 2
> motors on both axis, with Renco 1000 line encoders)
>
> Electro Craft DC Brush Servos 0644-06-011
>
> Continuous Stall Torque 192 oz-in
>
> Peak Torque 960 oz-in
>
> Maximum terminal voltage 60V
>
> Maximum operating speed 1850rpm
>
> Maximum pulse/peak current 22a
>
>
>
> If the motor says peak current of 22A, what would be the nominal operating
> current be ?
>
> Has anyone used the Gecko G320X with the Kflop motion controller, I'm still
> considering Snap amp. In fact I think Snap has slightly higher current
> rating than the 320x.
>
>
>
> Thanks in advance
>
> Marty
>
Group: DynoMotion Message: 598 From: Marty Escarcega Date: 8/21/2010
Subject: Re: Kflop and Gecko 320X servo Amps
:-)
Hi Carl. Haven't bought them yet. Makes more sense to stick with Kflop and
Snapamp.

Given my motor specs and that they are a pair and going on a lathe, how
would you size the power supply? A friend suggested get the voltage as close
to the servo max voltage, and build the power supply to be able to supply
the PEAK current, 22a. He suggested using several large capacitors.

Looks like Peak current on Snap Amp is 15A.
Would this power supply suffice and be safe and efficient to run both Servo
motors or would I need one for each motor?
http://cgi.ebay.com/56V-500W-Power-Supply-Gecko-Driver-CNC-Servo-Stepper-/37
0420959369

I like this one a little better as it has 5VDC, 12V/24VDC regulated power as
well.

Thanks in advance.
Marty


Group: DynoMotion Message: 617 From: carlcnc Date: 8/26/2010
Subject: Re: Kflop and Gecko 320X servo Amps
Marty
sorry so late, I don't visit the forum often

with only 2 motors I believe you can expect 20amp peak from the snap amp[right Tom??]
YOu should only need 1 supply but I would go for a 1kw
using an undersized one and adding lots of capacitors will probably cost more than a better supply
have a look at Antek power. I think they have a 60v 1 or 1.5kw with multiple taps,ready to go for around 160$ real bargain
carl

--- In DynoMotion@yahoogroups.com, "Marty Escarcega" <escarcega@...> wrote:
>
> :-)
> Hi Carl. Haven't bought them yet. Makes more sense to stick with Kflop and
> Snapamp.
>
> Given my motor specs and that they are a pair and going on a lathe, how
> would you size the power supply? A friend suggested get the voltage as close
> to the servo max voltage, and build the power supply to be able to supply
> the PEAK current, 22a. He suggested using several large capacitors.
>
> Looks like Peak current on Snap Amp is 15A.
> Would this power supply suffice and be safe and efficient to run both Servo
> motors or would I need one for each motor?
> http://cgi.ebay.com/56V-500W-Power-Supply-Gecko-Driver-CNC-Servo-Stepper-/37
> 0420959369
>
> I like this one a little better as it has 5VDC, 12V/24VDC regulated power as
> well.
>
> Thanks in advance.
> Marty
>
>
>
Group: DynoMotion Message: 618 From: Marty Escarcega Date: 8/27/2010
Subject: Re: Kflop and Gecko 320X servo Amps
Carl, thanks I see Antek has a website. They have a 63VDC 1.0kw and 1.5kw power supply. Fairly reasonably priced. I don't think the 3V over the max rated voltage of 60V would make a huge difference as its no load? Otherwise they make a 56VDC power supply for the same money and gives a margin of protection. How about Back EMF? Not an issue with Snap Amp?

Sorry for all the questions. I would rather do this right the first time rather than spend MORE money by buying the correct items, or letting the magic smoke out of something.

I bought matched servo motors to hopefully make tuning them easier. Tom already confirmed the encoders were fine.

I do have another question, I have to lengthen or replace the encoder cables. Should I purchase shielded wire or would twisted pair work fine? I was considering CAT5 cable but that wire is solid and wondered with the motion of the lathe carriage if it would eventually fatigue.

I have settled on KFLOP and SNAPAMP. (Do I read the specs correctly on snap amp, it can drive 4 DC Brush Servos? I only need to drive 2 on my lathe) While I can make breakout boards, are cables supplied to be able to utilitze the connectors or are those up to the user?

Thanks
Marty
---- carlcnc <cebcnc@...> wrote:
> Marty
> sorry so late, I don't visit the forum often
>
> with only 2 motors I believe you can expect 20amp peak from the snap amp[right Tom??]
> YOu should only need 1 supply but I would go for a 1kw
> using an undersized one and adding lots of capacitors will probably cost more than a better supply
> have a look at Antek power. I think they have a 60v 1 or 1.5kw with multiple taps,ready to go for around 160$ real bargain
> carl
>
> --- In DynoMotion@yahoogroups.com, "Marty Escarcega" <escarcega@...> wrote:
> >
> > :-)
> > Hi Carl. Haven't bought them yet. Makes more sense to stick with Kflop and
> > Snapamp.
> >
> > Given my motor specs and that they are a pair and going on a lathe, how
> > would you size the power supply? A friend suggested get the voltage as close
> > to the servo max voltage, and build the power supply to be able to supply
> > the PEAK current, 22a. He suggested using several large capacitors.
> >
> > Looks like Peak current on Snap Amp is 15A.
> > Would this power supply suffice and be safe and efficient to run both Servo
> > motors or would I need one for each motor?
> > http://cgi.ebay.com/56V-500W-Power-Supply-Gecko-Driver-CNC-Servo-Stepper-/37
> > 0420959369
> >
> > I like this one a little better as it has 5VDC, 12V/24VDC regulated power as
> > well.
> >
> > Thanks in advance.
> > Marty
> >
> >
> >
Group: DynoMotion Message: 621 From: Tom Kerekes Date: 8/27/2010
Subject: Re: Kflop and Gecko 320X servo Amps
Marty,
 
Regarding Back EMF as a big system decelerates energy gets pumped back into the power supply which can cause the power supply voltage to rise up and potentially damage components.  SnapAmp has a programmable clamp voltage that you should set a few volts above your normal max power supply voltage.   The big power resistors on SnapAmp can absorb several KW of power momentarily.  Take care not to set the clamp voltage to a voltage lower than your power supply.  SnapAmp allows you to plot your supply voltage so it is easy to see exactly what is going on with your power supply.  What the initial voltage is, how much it drops under load, how much it spikes up during deceleration, how the clamping functions, etc...
 
Regarding encoder cables:  you should use shielded with twisted pairs if possible.  Each pair of differential signals should be twisted together.  We don't supply cables other than those that connect our boards together (small 16 pin ribbon between KFlop and SnapAmp) and a USB cable.
 
Yes one SnapAmp can drive 4 brush motors.
 
Regards
TK