My interpretation.
If the drives have a bridge input then they would be able to use AC or DC, 80VAC will be = to ~110vdc when rectified and smoothed internally.
Al.
Hi All,
I was looking at a bunch of leadshine products today. There is something I am just not getting. Although I do try to read about things, I have only every put together one stepper control system for a CNC machine. So I think there is something basic here that I am not understanding.
For example, if you look at the Leadshine DMA860E
http://www.leadshineusa.com/uploadfi.../dma860e_m.pdf
it says you can have "Input voltage 18-80VAC or 24-110VDC"
I tried and failed to find examples of people using AC input to run steppers with a Leadshine driver. The manual only talks about selecting an appropriate DC power supply, and I can't find any mention of connecting to AC power. Yet, it's right there in the specs.
So with this driver, I can use a step down transformer using normal AC single phase power (to get it in the correct range) and I don't need to use a DC power supply? This would be to drive a Nema34 4 wire stepper motor. Is this true? What am I not understanding?
If I can do this, how does this translate to an equivalent DC power? For example, would I get the same performance using 80 VAC single phase input as I would using 80 VDC input from a power supply?
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My interpretation.
If the drives have a bridge input then they would be able to use AC or DC, 80VAC will be = to ~110vdc when rectified and smoothed internally.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
When you rectifier using a full wave bridge and follow it with a capacitor, the AC becomes AC x 1.414.
OR if 110VDC the the AC to create that will be 110v x .707.
There are some slight losses through the rectifier.
It is my guess they have a bridge input that allows AC or DC.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Thanks again for the replies Al!
I am thinking that the cost of a dc power supply and the cost of a single phase ac transformer will be about the same. Unless there is a way to reduce the voltage on normal 120V AC power without a transformer that I don't know about?
Has anyone out there used a leadshine driver like this with ac power input?
I just bought some Nema 34s that I'd like to run at 80Volts. I'm just trying to determine the best way to go about it. I have four gecko drives (201x) and a 48V supply already for use with the CNCRP 960 oz in motors.
The new Nema 34s are the 1232 Oz In variety, and I plan to use one for my Z axis and one for driving my Z carriage. The gantry has two motors driving it, so I'd leave that with the two 960 motors running on 48V as I don't need the extra torque there.
I need a new driver for my 4th axis anyway, so i was just thinking about using two of the leadshine ac drivers for the two 1232 oz in running at an equivalent of 80VDC, and using three gecko 201x that I already have for the remainder (running on 48 VDC that I already have).
I'm not sure what the best plan is. Not having to get another DC power supply could be handy.
What I generally do is look for a suitable Toroidal transformer and add/increase the secondary with an over-wind as needed.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Hi NIC,
Yes, the drive DMA860E can take both AC and DC power input, just keep in mind that the power supply must be in the range, otherwise, it's easy burning the drive.
Here i show you the relationship between AC and DC power, almost like DC=1.4*AC.
Thank you for your attention to Leadshine Products.
Thanks for the reply!
How sensitive are the drivers to over voltage? If I use an AC transformer, there will be fluctuations in the input line that I can not control.
That being said, if I used a 1:2 transformer, that would give 60VAC x 1.4 = the equivalent of 84VDC, so that's probably good.
I'm just curious if I use a transformer to get to 80 VAC, so 80 x 1.4 = 112 VDC, how much of a fluctuation in the input line do I need before something is destroyed? Is this going to pop right at 80 volts? How much of a safety factor do you recommend?
With Chinese stuff, if they say 80, then I'd stay at 70.
Gecko's, I believe, have a bit of headroom, and are safe to run at their rated voltage. The founder of Gecko used to be a regular contributor here before he retired. Really, really smart guy.
Keep in mind that you also have to worry about back EMF, especially when stopping a heavy load quickly.
Gerry
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That's a good point. From what I've read, this is why unregulated DC power supplies are preferred over regulated ones, and why it is suggested to have all motors running from a single power supply. Does that sound correct to you?
I have no idea how this translates into using a leadshine driver run from AC power? How does this effect the back EMF? Is it better or worse?
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Hi All , I am seriously considering using the DMA860E . It seems Ideal for my application . I going to retrofit a Bridgeport Boss 5 . I have 3 of these machines and finally tired of changing transistors and bridge rectifiers.
To me it makes sense to keep Bridgeport's main 3 phase T1 transformer, it can be tapped for 60 , 70 or 80 vac . Currently it's tapped at the 60 vac which is putting out 56vac to run the original superior steppers thru the huge original dc power supply.
I plan on keeping the original steppers for now putting the 56vac into the DMS860E and getting up to 78vdc to the motors at 7.2 amps . I'm going to control it with Centroids Acorn breakout board.
Am I doing the right thing ? this is my first retrofit . If it works out I will eventually do the other 2 machines.
Thanks, David