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  #31  
Old Mon 22 June 2009, 11:34
anton
Just call me: Anton
 
Cape Town
South Africa
Hi Gerald,

Would this torodial from Comunica in SA do the job?

3851.0200 TRF TOR25V6A TOR25V6A
Transformer Torroidal 300VA 2x25V 2x6A N/A

Anton
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  #32  
Old Mon 16 August 2010, 19:18
Mongkol
Just call me: Ton
 
Bangkok
Thailand
How to calculate and choose the switching power supply which is suitable?

Dear All,
I have the hybrid stepping motor and the driver.
I am finding what output voltage (DC) and ampere of swiching power supply is suitable for one stepping and one driver. I have the specification as detail below.

Stepping motor :
1.8 degree,2PH
Choose microstepping at 1600 pulse/rev
I choose to wire bipolar type
Current for bipolar : 2.8 A/phase
Resistance 1.6 +/- 10% ohm / phase
Inductance 15+/- 20% mH/phase

the driver :
need the power supply from 24 VDC to 80 VDC
I don't know how to calculate and choose the switching power supply.
I want to know the output voltage (DC) and ampere of the switching power supply is suitable for one stepping motor and one driver. Pls advise me.

Hope your help
Mongkol
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  #33  
Old Mon 16 August 2010, 21:58
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Mongkol,

The inductance of the motor determines the voltage that you can use. 15mH inductance lets you use up to 123VDC. The Geckodrive stepper drivers can only handle 80VDC, so you would use a 55VAC toroidal transformer to get about 80VDC. You need about 100VA current available per stepper motor, so for four motors, you would need about a 400VA transformer. A 10,000 uF capacitor would be more than adequate.

If you use a switching power supply, pick the closest match of 80VDC or LESS. You should still add the 10,000 uF capacitor to the outputs of the switching power supply.

Not all stepper drivers are as efficient as the Geckodrive G20x series and not all stepper drivers can handle 80VDC. Check the specifications of the stepper driver before attempting to use it with 80VDC. It may have a lower maximum voltage. If either the motor or the stepper driver gets too hot, reduce the voltage of the power supply.
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  #34  
Old Wed 18 August 2010, 09:20
Mongkol
Just call me: Ton
 
Bangkok
Thailand
How to calculate and choose the switching power supply which is suitable?

Mike,
Thanks so much for your help.
My friend advise me with switching power supply at 24 VDC,300W for 3 axis.
I am not sure this is correct or not.
Assume,If I need and use high torque and high speed,Is it enough to use with this spec. of this switching power supply ?

Mongkol
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  #35  
Old Wed 18 August 2010, 10:40
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Mongkol,

Twenty-four volts would make the motors turn, but you wouldn't get very much speed. Usually the speed of the motor is mostly affected by the power supply's voltage and the torque is mostly affected by the power supply's current (Amps).

Some stepper drivers require a MINIMUM of 24VDC just to operate (G201, G202). Some can work at 15VDC (G203v). Check the specifications on your stepper driver to see if their is a MINIMUM voltage specification.

300W for 3 or 4 motors would work. 2.8A X 24V = 67.2VA and 67.2 X 4 motors = 269VA. In a DC power supply VA = Watts.

You should still put a 10,000uF capacitor on the output of the switching power supply. A stepper motor is not a constant current device. It will draw as much current as it needs when it needs that current. The capacitor acts as a "current resevoir" to store that needed current.

For high-speed, you should probably use a power supply that is close to 80VDC (assuming that your motors have 15mH inductance).
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  #36  
Old Wed 18 August 2010, 13:43
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Switching power supply.

Mike,
You describe very well. Thank you so much of the share from your experience. Normally, It's difficult to find the switching power supply at 50VDC to 80 VDC and the high ampere at here.
In the thailand market,It's only power supply 24 VDC to 48 VDC.
50 VDC to 80 VDC and the high amperes,It may have a high cost .
Do you have the other methods to advise me?

Mongkol
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  #37  
Old Wed 18 August 2010, 19:49
riesvantwisk
Just call me: Ries #46
 
Quito
Ecuador
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Ton,

you could use a very classic setup by putting two normal transformers in series and as such get a higher voltage. However, using 15-20mH/phase seems very high, and I wonder if the response time of these motors are any good. I am not a guru on the subject, Mike knows that much better, Mike can you shine a light on that?

I would see if you can get steppers in around 4mH/phase and then work within a easer voltage range. With these lower voltage ranges it's also easer to find drivers.

Ries
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  #38  
Old Thu 19 August 2010, 05:00
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Ries is correct in suggesting to put some power supplies in SERIES. I often put two 24VDC switching power supplies in series to get 48VDC. Three 24 VDC power supplies in series would give you 72VDC.

I also agree that it is not good to use a motor with high inductance. ALL of the motors that I use have an inductance of 3.5mH or less when wired half-coil or bipolar parallel. I DO NOT wire motors bipolar series. When wired bipolar series, all the motors that I have tested have excellent LOW SPEED torque but very low torque at normal speeds. For instance, I can easily drive all my motors at 1,500 RPM when they are wired half-coil, but I can't drive them faster than 350 RPM to 500 RPM when they are wired bipolar series - unless I give them extremely long ramp times (low acceleration). The Oriental Motor torque charts show graphically what happens to motors that are wired bipolar series compared to what happens when they are wired unipolar. Geckodrive stepper drivers can only be used bipolar. Unipolar is not an option; therefore, I wire the motors half-coil, which is another way of saying bipolar single coil.

I have tested all my motors with the Geckodrive G540 stepper module ($250 to $300 depending on your supplier). I limit the current to 3.5A per motor by choosing the correct current limiting resistor and I have to limit the voltage to 50VDC, but that still allows the PK299-02AA motor to be driven faster than 1,000 RPM. The Geckodrive G203v is even better. It allows voltages to 80VDC and currents to 7A per motor. None of my motors require a power supply greater than 50VDC, but several of them are rated at 6.3A. Using the G203v with proper power supply, I can easily hit 1,500 RPM.

Keep in mind that the PK296A2A-SG7.2 motor should NOT be run faster than 250 RPM. So 250 X 7.2 = 1,800 RPM. With a 1.25" diameter spur gear, that would still give you about 16" per second jog speed (approx. 950 inches per minute). The weight of the gantry may limit that speed. My Shopbot has a lot of aluminum in its gantry, so my speeds may be higher, but the flex in the machine is also much higher.

For those who can get the parts and who only need a minimal system, I recommend the Geckodrive G540 and the Oriental Motor PK296A2A-SG7.2 motors with a 35VDC power supply. My motors on the test bench are the PK296B2A-SG3.6, which are electrically equal to the PK296A2A motors. The gear box is 3.6:1 instead of 7.2:1. The G540 can drive those motors just as hard and just as fast as the G203v. No break out board is needed, but the G540 only has two general purpose Outputs and four general purpose Inputs.
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  #39  
Old Thu 19 August 2010, 08:48
KenC
Just call me: Ken
 
Klang
Malaysia
Mogol, almost every known MM built utilise conventional transformer. Switch mode power supply isn't the best solution for stepper motor. I'm sure you can source EI-core transformer in Bangkok, maybe even custom wind one at a fraction of the equivalent SMPS.
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  #40  
Old Sun 22 August 2010, 07:08
Mongkol
Just call me: Ton
 
Bangkok
Thailand
Ries,Mike and Ken,
Thanks so much for the idea.

Mongkol
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  #41  
Old Sat 25 February 2012, 04:49
andrewhopps
Just call me: andrewhopps
 
NJ
United States of America
After countless reading through this and other sites...

I still don't understand how to get these numbers correct. If someone could help me with a personalized response how to get the correct numbers from my selection.

3 x KL23H256-21-8B
2.4 Inductance ( Bipolar Parallel)
3 Amps Current Per Phase ( Bipolar Parallel)

After getting those numbers, how do I decide on drivers? Could I use 3 x kl-4030?

Last edited by andrewhopps; Sat 25 February 2012 at 05:00..
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  #42  
Old Sat 25 February 2012, 09:23
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
On the KL-4030 data sheet is says: "Suitable for a wide range of stepping motors of Nema 17 and 23". The motor that you've specified is a large Nema 34 motor.

The calculations that we normally use to figure maximum voltage was published by Geckodrive for Gecko Stepper Drivers. Those figures may or may not work with stepper drivers from other manufacturers. The Geckodrive G201x or the G203v would work very well with the motors that you selected. You could use a power supply up to 50VDC, with 35VDC being my suggestion. You might be able to use the G540. It falls within the specifications, marginally. You would probably be better off wiring the motors half-coil if you decided to us the G540.

Someone else will have to advise you about using Keling Stepper Drivers. I've had no experience with them.
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  #43  
Old Sat 25 February 2012, 11:16
danilom
Just call me: Danilo #64
 
Novi Sad
Serbia
They would be a tight fit, as you would put it to its maximum. you need around 45V for 2.4mH and 3Amp.
Better option if you are on a budget would be a KL-6050 or KL- 5042, and you might consider Gecko G540 which is good for 3.5Amp and 50Volts and has a BOB integrated.

What I failed to see on first looking at the datasheet is that is an small Nema23 motor with only 1.3Nm , that would not be sufficient to drive a machine such is the Mechmate
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  #44  
Old Sat 25 February 2012, 15:49
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Thanks Danilo for catching my oversight. I looked at the KL23 Nema 23 motor and my mind played tricks on me (again). I thought that I was looking at a Nema 34 motor.

A size 23 motor can be used, if you use the right gearbox or belt-drive. It would be fairly easy to match pulleys to get a 6:1 or a 7.2:1 ratio. Doing that would easily multiply the motor's torque so that the motor could handle the job.

Notice that I used the words, "can" and "could" carefully. Using a long enough belt so that enough teeth were always engaged means that the size 23 motor would be more bulky than a size 34 motor with belt drive. A long belt also means that there would more elasticity in the belt, which just another way of saying "backlash".

My choice would still be a size 34 motor connected through a 1:3 to 1:4 belt-drive. That design has been tried and proven. It works. The costs are reasonable.
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  #45  
Old Mon 07 May 2012, 17:33
Axel1966
Just call me: Axel
 
Paris
France
I just want to check out my calculs :
I've selected these motors : 5.5A 4mH (SY85STH80-5504B)
- 32*√4 = 64V
- 5.5A*4 = 22 ; 22*67% = 14.74A ; 14.74x64 = 950VA (943.36)

So I should get a 64V 1000VA power supply. Am I right ?
It sounds so huge to me (hard to find and pretty expensive) through, steppers does not look extremely powerfull.
I should have done a mistake somewhere...

Last edited by Axel1966; Mon 07 May 2012 at 17:50.. Reason: dummy
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  #46  
Old Mon 07 May 2012, 19:37
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
http://www.antekinc.com/pdf/PS-10N63R.pdf


Here it's about 180.00 1000 watts @ 63 volts with 12volt and 5 volt taps too.
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  #47  
Old Mon 07 May 2012, 22:25
KenC
Just call me: Ken
 
Klang
Malaysia
Axel, I ended up with your predicament when I 1st tried to work out the transformer size. That is what we were exposed to. BUT there is another way to determine the transformer size.

Logically, similar machine with similar mechanism, weight & duty should require similar power (watt) to operate. since VA is a very close approximation of watt. AFAIK, 300VA tranny is the accepted " standard "transformer size which most MM operated on without excessive hot transformer.
Disregard of the voltages of the transformer, 300VA transformer should do the job for you. If you like you can go for 400 or 500VA just to be on the safe side. but using a 1000VA seems like overly paranoid...
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  #48  
Old Tue 08 May 2012, 00:21
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
1000VA transformers need a big inrush current when they switch on. This gives problems to quite a few people.
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  #49  
Old Tue 08 May 2012, 02:28
danilom
Just call me: Danilo #64
 
Novi Sad
Serbia
Be carefull with this calc, you need 64 Volt AFTER the capacitors!
the transformer voltage should be √3 times smaller than 64V

I use a 17amp 34V transformer for two years with no problems, standard EI core not toroid
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  #50  
Old Tue 08 May 2012, 04:30
Axel1966
Just call me: Axel
 
Paris
France
Thanks you all for your wise advices. And for the link Sean
I was listing all the power supply and motors specs in the 'MM already cuting section'
That saves me a lot of time.

I'll go from a 300VA to 500VA depending on oportunities.

Just a fiew last questions on these subjects sirs,
I see some kit configurations with several "in box" power supplies.
I mean : 2x 200W 48VDC 4.2A (for 4x1200oz.in steppers)
or 4x 350w 60vdc 5.8A (for 4x1600oz.in steppers)

How to calculate a multiple power supply configuration ? A simple division ?
For example 300VA needed = (4x75VA) power suplies ?

As far the "in box" power supply's output voltage is alowed by the stepper driver,
(for example from 18 to 50vdc) is there a preferency to choose 48v instead of 24v or 36v ?
I apreciate the Intensity might be superior with 24v and inferior with 48v,
but is it right to think it will be pretty the same ?
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  #51  
Old Tue 08 May 2012, 07:35
bradm
Just call me: Brad #10
 
Somerville(MA)
United States of America
1200 oz.in or 1600 oz.in steppers seem awfully big for this application. That could be why your power supply calculation ended up so high. Check the motor selection threads
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  #52  
Old Tue 08 May 2012, 08:31
Axel1966
Just call me: Axel
 
Paris
France
You get me wrong Brad, that was just examples picked up into existing retail kits.
Quote:
Originally Posted by Axel1966 View Post
(...) I've selected these motors : 5.5A 4mH (SY85STH80-5504B) (...)
I've read a lot the Motors selection tread.
It's 4.6 Nm motors, with a 3:1 belt reduction, they should be fine for the work, not overpowered.

Last edited by Axel1966; Tue 08 May 2012 at 08:34..
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  #53  
Old Tue 08 May 2012, 08:32
danilom
Just call me: Danilo #64
 
Novi Sad
Serbia
SY85STH80-5504B motors are just right at 650 oz.in
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  #54  
Old Tue 08 May 2012, 14:19
bradm
Just call me: Brad #10
 
Somerville(MA)
United States of America
Sorry, I missed that Axel. As long as you aren't going into unreasonable levels, E.G. >32x inductance, then higher voltages may give you better acceleration than lower, so 48v would be preferred to 24v.
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  #55  
Old Tue 08 May 2012, 15:20
Axel1966
Just call me: Axel
 
Paris
France
I get it, thank you Brad
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  #56  
Old Thu 10 May 2012, 06:32
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
VA = AMPS * (VDC * (1 / (SQRT(2)))

So, 15 A * 65VDC * ( 1 / (SQRT(2)) = 15 * (65 * (0.7071)) = 750 VA

The AC volts rating is used, not the DC volts rating. The large filtering capacitors remove most (95%) of the AC ripple on a DC power supply. If you use 15,000 uF to 20,000 uf capacitors (several capacitors in parallel, if needed), a 750 VA power supply and a 25A 400V bridge rectifier, you'll have just what you need for heavy duty work.

The bridge rectifier specified costs about the same as smaller units, which is why I don't use smaller units.

75 volt to 100 volt "snap caps" in the 6,000 uf to 10,000 uf range are plentiful and fairly inexpensive compared to the large "can" types that most people use. Look at some of the photos to see how builders have connected "snap caps" together in parallel with nylon wire-ties and heavy gauge connecting wire.

You need caps whose voltage is rated at 150% of the AC value of the transformer because AC is measured using RMS and DC is measured at peak values. DC is SQRT(2) X AC, or 1.414 times higher than the the RMS AC value. That's why you need caps whose voltage is rated at 150% of the AC value of the transformer.
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  #57  
Old Thu 10 May 2012, 07:41
Axel1966
Just call me: Axel
 
Paris
France
Many thanks Mike, it's all I needed.
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  #58  
Old Sat 03 August 2013, 10:24
Fox
Just call me: Fox
 
Amsterdam
Netherlands
Quote:
I recommend to select the power supply voltage 20% higher than that formula. The motor heating can be controlled by a simple setting of the drive/motor current.
Am I correct in my assumption that Geralds recommendation in the openingspost is still valid (with my specs-see below), and that the reasoning behind this added 20% is that the calculation before the added 20 % will give you the unregulated DC power output, and this voltage will drop when under load ( which can be as much as 20 % ) hence the recommendation ?

My calc then gives me: V4.1x32= 64.79V + 20 % = 77.75 V = 77 volt DC output ( just within driver max 80 V )

Bipolar parallel current = Unipolar current X 1.414
5x5.65=28.28x0.67=18.94x64,79=1227.61 VA/Watt
which could be halved ( read this on the forum ) because all motors will not be asking full power simultansouly ?
1227.61 VA/Watt - 50 % = 613.805 = 600 VA ?

(5xMotor DEITECH 86HS9801 - driver LEADSHINE AM882 bipolar parrallel)


Sounds safe/no risk of magic smoke apparent ? Thnx in advance, bit scared to make stupid mistakes on this, this is my last check before ordering.

Last edited by Fox; Sat 03 August 2013 at 10:45..
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  #59  
Old Sun 04 August 2013, 20:21
KenC
Just call me: Ken
 
Klang
Malaysia
Quote:
Originally Posted by Fox View Post
5x5.65=28.28x0.67=18.94x64,79=1227.61 VA/Watt

(5xMotor DEITECH 86HS9801 - driver LEADSHINE AM882 bipolar parrallel)[/SIZE]
why 5x motor?
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  #60  
Old Mon 05 August 2013, 07:11
Fox
Just call me: Fox
 
Amsterdam
Netherlands
Hey Ken,

I get all exited that someone answers me and confirms/denies my electrical assumptions (that's really what they are).... so I can order the last stuff.... turns out you posted only a question ....so do have any answers to my question before I answer yours ?

Just kidding; My plan for world domination requires 5 motors instead of the usual 4 because of a 4th axis or double Z

Last edited by Fox; Mon 05 August 2013 at 07:25..
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