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  #61  
Old Mon 20 August 2007, 08:59
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
In browsing the oriental motor website, I noticed that they now have 9, 10, 18 and 36 to 1 gear ratios available in this motor line. Gerald, or anyone for that mater, what do you think about going higher than 7.2 : 1? The higher torque might give a better cut quality.

Also, the 2 amp motor seems to have a lower voltage coil and a lower inductance. Seems to me that if your driver can handle the 2 amps, then maybe this would be a better choice than the 1 amp? Lower inductance should mean better acceleration and torque?

Any comments anyone?
  #62  
Old Mon 20 August 2007, 09:39
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
High ratios could be useful if:
- There is a true higher torque. Even the 7.2 gearbox doesn't allow you to use 7.2 times the torque of the ungeared motor. Mechanical limitations on bearing loads, shaft strengths, etc.
- There isn't any additional backlash.
- Your computer/controller/drive can run at the higher frequency required.
If you want to do some experimenting, let us know what you find

The 1 Amp motor with 3.6:1 gearbox developed sufficient torque to break 1/2" cutters. Can't an obvious reason why a 2 amp motor would be "better".
  #63  
Old Mon 20 August 2007, 10:31
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Gerald,
Do you think the 3.6 geared motor provides better resolution and better cut quality than the direct motor? I was thinking of the 10 : 1 motor as it would be a nice divisor and provide more resolution for better cut quality?
  #64  
Old Mon 20 August 2007, 11:09
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
The main problem with high gear ratios is the number of steps per second that it takes to move along an axis. For instance, using the popular 30 tooth pinion that has a pitch diameter of 1.5 inches, moves the axis 1.5 X pi or 4.71 inches. Because a Gecko G20x stepper driver requires 2,000 pulses to rotate the shaft one time, each stepper pulse on a 1:1 (non-geared) motor would move the axis 4.71/2000 or 0.002355 inches, which is also 424.628 steps per inch. If we were to use a 3.6:1 geared stepper motor, it would take 424.628 X 3.6 = 1528.6608 pulses to move an inch. Mach 3 has a top speed through the parallel port of 45,000 pulses per second (on my computer). That means that Mach 3 could move/jog an axis at 29.43 inches per second with a motor geared 3.6:1 (if the ramping was perfect and no gremlins were active on that particular day; however, getting 1/2 that speed would still be a notable feat).

Going to 10:1 gear reduction would require 4246.28 steps per inch. Top jog speed would be reduced to about 10 inches per second (with 5-ips being more realistic).

More importantly, as Gerald pointed out, the gearboxes used on the PK296A1A-SG series motors are NOT famous for being particularly strong or accurate. The are limited in the amount of torque that they can handle and they have some backlash. For most normal CNC work, I would pick the 3.6:1 gearbox or the 7.2:1 gearbox. Personally, I have four of the 3.6:1 gearboxes on my test bench. If and when I ever get around to building a MechMate, I'll most likely use those motors.
  #65  
Old Mon 20 August 2007, 12:20
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Quote:
Originally Posted by domino11 View Post
Gerald,
Do you think the 3.6 geared motor provides better resolution and better cut quality than the direct motor?
Going by all reports, and following common logic, the 3.6 geared is better than direct, though I have no personal experience of it. The 7.2 seems to be the even better option (again, going by reports). 10:1 is not spoken of, and it is not even slightly important to use "nice" numbers.
  #66  
Old Mon 20 August 2007, 12:22
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Mike, Art recently found a way to get much higher speeds out of his Mach engine, which is apparently standard now. (Something like 100khz without changing the PC?)
  #67  
Old Mon 20 August 2007, 16:24
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Gerald,

Thanks for the info about the higher Mach 3 speeds. I haven't downloaded anything from Art since the stable G100 plugin became available. (I receive dozens of Mach forum messages every night, but usually I just quickly scan the headers to see if there's anything I need - somehow I totally missed the higher speed pulse rate.) At any rate, I've just downloaded the latest software and will soon be testing it at my test bench.
  #68  
Old Tue 21 August 2007, 05:25
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Mach 3, at 100kHz, is wonderful! For the first time, I can make the motors on the PMDX/Gecko G202 test bench act as though they were the motors on the G100/G203 test bench.

At 100kHz, gear ratios higher than 7.2:1 could be used, but, in my opinion, either the 3.6:1 or the 7.2:1 would still be my preference.

Edited: We need to remember that, even though Mach 3 at 100kHz can spin the motors much faster, the torque requirements on a motor will probably dictate that the motor be used at moderate speeds, the speed range where a stepper motor has the most torque. What I am thinking about, however, is that higher ratio geared motors could be used if good quality gear boxes were used (expensive, more than $800 per gear box) or that brushed servos could be used (also expensive because the ones I've tested are useless without a high ratio gear box). The advantage to using servo motors is that the torque curve seems to be constant throughout the motor's speed range, but the available torque is only a fraction of that available from a smaller and lighter stepper motor. For instance, I have a 34-size brushed servo (ID33004) that is long and heavy and has only 170 oz*in of torque at 70V. However, at 70V, that motor can run all day long at 2,200 RPM. So, with a 7.2:1 or 10:1 gear box to multiply the torque and to divide the speed, that particular motor might be useful on a CNC router. The problem of course is that even though the motor and Gecko G320 servo driver costs almost the same as a Gecko G20x stepper driver and a 600 oz*in stepper motor, the servo requires a gearbox - meaning that a MechMate with servos would probably cost at least $4,000 more than a MechMate with steppers.
  #69  
Old Wed 05 September 2007, 10:40
javeria
Just call me: Irfan #33
 
Bangalore
India
Hi All,

How about http://www.linengineering.com/site/products/8718.html , i have a quote from them for model 8718S-05P around 250 USD each. Do you all think vexta is better, i think i should find a dealer for vexta here in bangalore

rgd
IRfan
  #70  
Old Wed 05 September 2007, 23:01
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Suggest you first find the Vexta price before you decide which company is the better supplier. On paper, the motors are very similar.
  #71  
Old Thu 06 September 2007, 04:33
javeria
Just call me: Irfan #33
 
Bangalore
India
Quote:
Originally Posted by Gerald D View Post
Suggest you first find the Vexta price before you decide which company is the better supplier. On paper, the motors are very similar.
I got the quotes from Vexta distributers its almost 300USD for the ungeared and around 365USD for the geared (3.2) without taxes.

ho ho.............
  #72  
Old Thu 06 September 2007, 09:14
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Have you considered importing from Motionking, China? They might even tell you they have a stockist/agent in India.
  #73  
Old Tue 11 September 2007, 21:07
thesaent14
Just call me: Manny
 
Miami
United States of America
Quote:
Originally Posted by Gerald_D View Post
Sorry, too small and underpowered.
i guesst you just answer my first Q?

is funy geral i just read this hall and you send me back here lol

well a bit about my motors i have a set of super vexta 5-phase motors with there drivers here is a picture of them in my small machine

this are the drives

and this are the motors


can any one tell me if any of this is good to install in my machine
  #74  
Old Tue 11 September 2007, 22:55
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Here's a link to an Oriental Motor document that shows the why there are 2-phase motors and 5-phase motors:

http://www.orientalmotor.com/MotionC...hase-intro.htm

Read it carefully, and it will answer most of your questions.

My own opinion on the matter is that I would NOT use 5-phase motors. Using 5-phase motors means that I would NOT be able to use Gecko G20x stepper drivers. To me, the 5-phase motors are like the Oriental Motor Alpha drivers/steppers that I have on my Shopbot PRT-Alpha machine. The motors and the drivers are a package - a very expensive package. Just one motor/driver costs about $1,100 retail. Gecko stepper drives cost less than $150 each and the motors cost about $200 each. So for about $1,400 plus another $100 for a power supply, I can buy four motors and four drivers and a power supply that has much better resolution that the Oriental Motor Alpha driver/stepper.

Right now, I have two of the 23 frame size 5-phase stepper motors and drivers and one of the 34-frame size 5-phase stepper motors and driver. None of them have ever been used. Very possibly, none of them will ever be used. Why? Because, if I build them into a machine, I will have to support them and replace them in the event that one fails. That costs too much to make it practical. So, unless I find a way to use them in one of my own projects, I probably won't use them at all. (Please don't ask me to sell them at 10 cents on the dollar. Deep down, I am a business man and as a business man, I don't give away expensive parts and pieces. Sorry, but there is a line between giving advice freely and giving away parts and pieces that cost a lot of money to buy. Even though those motors and drivers may have very little value to anyone else, they still cost more than $3,000 to buy. As far as that goes, I also have about $15,000 worth of Ziatech STD-32 controllers on hand. I bought those shortly before Ziatech was bought by Intel. Those boards are all factory new - but will never see life in a new machine for the same reason - it's simply much cheaper to buy a Z-World processor and design a process control computer around the Z-World processor than it is to use the Ziatech parts that are sitting on my shelf. Just so I don't sound too mercenary, how would you feel if I sold you a process control computer that had all new parts but when the machine broke I told you that the manufacturer had gone out of business; therefore, I couldn't service your brand-new machine? Sometimes we get a little bitter when suppliers that we trust suddenly close their doors without warning us. That happened to me with Ampro computers and their Little Board Z80, with Ziatech with their STD-32 line and with Oriental Motors with their 5-phase Vexta line. In the case of Oriental Motors, they still make other fine 5-phase motors and drivers, but I've decided to use their 2-phase motors with Gecko drivers to get the best value for my money.)
  #75  
Old Tue 11 September 2007, 23:13
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Manny, have you tested those motors and drives? Do they work smoothly for you?

What is the diameter and length of the output shafts? (Notice that all three motors are different). We are looking for a 1/2" shaft more than 1.25" long.

There is a chance you might be able to use a motor for the z-axis . . . .

(PS. I spent nearly an hour looking for specs on those Vexta motors in the photo. At $150/hr (my day job rate), you owe me about ?? beers )
  #76  
Old Wed 12 September 2007, 16:12
thesaent14
Just call me: Manny
 
Miami
United States of America
geral D my motors are 1/2" shaft and 1.25" long and i am working with them in my machine now they do work really good and smoth

btw

i have a 24 pack

this is my machine now the pictures are old i do have 3 of the motors and the drivers are the same.
  #77  
Old Wed 12 September 2007, 20:22
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
There is a *possibility* that these motors could work for the y and z-axis. I am afraid that you will have to experiment.
  #78  
Old Wed 12 September 2007, 20:44
thesaent14
Just call me: Manny
 
Miami
United States of America
how about if i get the new motors and use the drivers i have now if you see the in the pictures those are the vexta drives the model number is UDX5128NA

i was reading on the page about the 5 and 2 phase i probably will be able to get away with it
  #79  
Old Wed 12 September 2007, 20:55
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
5-phase steppers are basically obsolete, a museum might be interested in that driver and motor. (I seriously spent a long time looking at your drivers and there was just no info, which means they probably went off the market before the internet existed)
  #80  
Old Wed 12 September 2007, 21:04
thesaent14
Just call me: Manny
 
Miami
United States of America
i guest i least words lol don't use them i will have to go with the ones you recomend well ebay will have some new items now i am looking to start this machine really soon
  #81  
Old Thu 13 September 2007, 05:32
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Manny,
If the drives and motors run, they can be used. The 596 motor will have torque similar to a PK296 motor (about 300 oz*in). You may have to build a belt-drive gear box to get enough torque to use it. The 5913 motor will have torque similar to a PK2913 (about 900 oz*in). That motor has would work without a gear box. The 566 motor is probably too small to be useful on a CNC router. It is similar to a PK266 motor (about 125 oz*in). Because it has a 0.25-inch shaft, it is probably too light, even with 7.2:1 gearing (10-tooth to 72-tooth timing belt pulleys).

Because Mach 3 has excellent ability to handle motor tuning, almost any motor can be used.

My main concern is that you may have to do a lot of extra work just to make the motors useful (belt drive transmission). You will end up with a motor that has 1/4th the resolution of a Gecko driven motor. With the addition of a belt-driven transmission, your cost will actually be equal to or more than buying a new PK296A2A-SG3.6 or PK296A2A-SG7.2 motor (at least in the USA).

No matter what you decide to do, always remember that a Mechmate, with all of its excellent features, will only work as well as its motors. Using strong, smooth motors will let the machine do all that it is capable of doing.
  #82  
Old Thu 13 September 2007, 16:04
thesaent14
Just call me: Manny
 
Miami
United States of America
can i use all my drives and buy the motors if is not that bad if i can't them i will go with the geckos and the motors Gerald recommend
  #83  
Old Thu 13 September 2007, 16:08
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Sorry, Manny, but I misunderstood. Each motor must be matched to its own driver. A driver for a 566 motor with not work with a 596 motor, etc. Unless you have matched drivers and stepper motors, then I would suggest that you buy the Geckos and the motors that Gerald recommends.
  #84  
Old Thu 13 September 2007, 16:17
thesaent14
Just call me: Manny
 
Miami
United States of America
i think i will go with those on least the is any other working choist if not i will get them i just don't want to spend the money if i got the posibility of use them you know i guest i am stuck with all this motors and drives

btw

you can use the diprent drivers and motors as long they have they both have the same wire colors
  #85  
Old Wed 31 October 2007, 14:50
joepardy
Just call me: Joe
 
Lebanon, OH
United States of America
5 axis design & power supply questions

Gerald,

I think that I have read through every post on motors, gearboxes, controllers, and drivers in this forum over the last few days - and though it may not be conflicting - it can get confusing .

I am looking at building a MechMate with a BC head. Ultimately I would like to build a 4x8 machine with a 24" Z axis. I have designed and am about to begin building the BC head. I have selected the following hardware/Software so far:

(1) Gecko GRex-100 Controller (6 axis)
(6) Gecko G203V Drivers
(4) PK296A2A-SG (3.6 or 7.2) Series Oriental Motors (X,X,Y,Z Axis)
(2) PK264A2A-SG (7.2 to 36) Series Oriental Motors (B,C Axis)
Mach 3 Software with G100 Firmware Upgrade

I beleive that this configuration will "work", but I would like to have your input.

Also, with this configuration, can you recommend a "pre-built" power supply? At a minimum, I would like it to be able to handle the power requirements of the controller, drivers, and stepper motors.

I do plan on adding some other "bells and whistles" in the future (vacuum table, motor on/off, etc.) so a little extra would power for the control relays wouldn't hurt.

I am much more "mechanically" inclined than I am "electrically" proficient - hence the hesitation to build my own power supply.

Again, your wisdom & knowledge would be greatly appreciated.
  #86  
Old Wed 31 October 2007, 17:34
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Joe,
I know that you addressed your post to Gerald, but, if you don't mind, I'll give you my input (and it certainly won't hurt my feelings if Gerald advises something different).

First off, you've made an excellent choice of motors, Gecko stepper drivers and pulse generator. I have almost the identical parts on hand on my test bench and have had absolutely no problems with any of the parts.

To determine which power supply will work best, you must decide whether you want to wire the motors Bipolar Series or half-coil. I strongly suggest that you choose half-coil to get much better response at higher speeds, but you will lose about 30% of the low-speed torque if you choose half-coil. Assuming that you decide to use half-coil wiring, the PK264A2A-SGxx motor will determine the maximum voltage. That motor is rated at 1.4mH (half-coil), so 1000 * SQRT(0.0014) = 37VDC MAXIMUM. I've had excellent results with a 27VDC power supply with the PK295B2A-SG3.6 motor (which is just the PK296A2A-SG3.6 motor with dual shaft). Current requirements would be ((4 X 3A) + (2 X 2A)) * 0.66 = about 11A MINIMUM. And 11A X 30VDC = about 350VA. I would select a 500VA power supply to give some margin.

If you decide to wire the motors Bilevel Series, then the forumula for the PK264A2A-SGxx motor is: 1000 * SQRT(0.0056) = 75VDC MAXIMUM. Personal experience dictates that a power supply voltage of 50V to 70V will work fine, with my personal preference being a power supply that is closer to 50V than to 70V. Current requirements would be ((4 X 2.1A) + (2 X 1.4A)) * 0.66 = about 7.5A MINIMUM. And 7.5A X 60VDC = about 500VA. I would select an 700VA or 800VA power supply to give some margin.

AnTek has a PS-5N30 power supply (30V @ 500W) for $100. They also have the PS-8N54 (54V @ 800W) for $120, which is only $10 more than the PS-6N54 (54V @ 600W).

The G100 comes with its own wall-wart power plug to generate the necessary voltage, so you won't need any other voltages unless you add other unspecified parts and pieces.
  #87  
Old Thu 01 November 2007, 00:44
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Joe, I got stuck at "BC head" - what is that?

Mike is the right guy to speak to regarding the electrics.
  #88  
Old Thu 01 November 2007, 02:28
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
'BC' would normally be 'tilt' and 'swivel' capability for the Z-axis. So, the machine would be able to have six-axes of movement. Most machines have three axes of movement, X, Y, and Z. Some include an A-axis, which is normally the Indexer to enable the machine to cut around a cylinder. The 'BC' movements could probably be thought of as the ability to dish out a bowl, cutting both the inside of the bowl and the outside of the bowl without re-fixturing the bowl.

While controlling all six axes is possible with the Gecko G100 controller, I can't even start to imagine using software to design and to toolpath all six axes.
  #89  
Old Thu 01 November 2007, 04:10
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Venturing into A territory was bad enough - I'll watch this B and C from the sidelines.
  #90  
Old Thu 01 November 2007, 04:44
joepardy
Just call me: Joe
 
Lebanon, OH
United States of America
Mike,

THANKS for the recommendation. I will put the PS-8N54 on my parts list.

Gerald,

The BC head is similar to what Rainnea and/or Colin have on their systems.

Thanks again for the help!
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