[yoopertool]

Has anyone used drives from this company. The price is good, but I am VERY nervous about the product:

http://cgi.ebay.com/3-PC-Nema-34-Ste...item2a036c3dce

[Crevice Reamer]

Has anyone used drives from this company. The price is good, but I am VERY nervous about the product:

http://cgi.ebay.com/3-PC-Nema-34-Ste...item2a036c3dce

Hi yooper!

Those are HUGE stepper motors. What do you want to drive with them?

They are wired internally for bipolar series. Their best speed Voltage would be ~150V. They will run fairly slowly at 24V

CR.

[yoopertool]

I have a 4'x5' router table I was thinking of putting them on. So it sounds like the package they are offering is poorly matched? I am actually more interested in the drives than anything else. Any input on those? Thanks again.

[Crevice Reamer]

How are you driving this router? Rack & pinion? Acme, (what thread) Ball screw?

CR.

[yoopertool]

I have 1" pitch ballscrews (48" long). I currently have a pretty scabbed together electrical set-up including 425 oz-in steppers from Keling inc. with a 3:1 timing belt reduction with a junky AlienCNC 4-axis driver and a 24V switching power supply. I have been getting some pretty bad step losses (pretty well stops) if I go any higher than 100 IPM. I am also not getting the torque that I need. I think that alot of this is due to the bad driver and small power supply, but I dont want to get better ones sized for my motors and still have it be underpowered. I am trying to get the most bang for my buck here, so any suggestions would be appreciated. Thanks.

[Crevice Reamer]

I have 1" pitch ballscrews (48" long). I currently have a pretty scabbed together electrical set-up including 425 oz-in steppers from Keling inc. with a 3:1 timing belt reduction with a junky AlienCNC 4-axis driver and a 24V switching power supply. I have been getting some pretty bad step losses (pretty well stops) if I go any higher than 100 IPM. I am also not getting the torque that I need. I think that alot of this is due to the bad driver and small power supply, but I dont want to get better ones sized for my motors and still have it be underpowered. I am trying to get the most bang for my buck here, so any suggestions would be appreciated. Thanks.

OK. You are running 85V motors at 24V. That's part of the problem. Then you are gearing the motor down 3:1. that is another problem. Plus your driver is probably suffering resonance losses.

Steppers have their max torque while standing still. Every RPM up from that loses torque. By gearing down, you are causing it to run 3 times faster than necessary, and at that point most of the torque is gone.

The lowest cost/quick improvement will be to gear those motors 1:1.

But if you want professional speed & reliability invest $350 to get a G540 and 48V PSU. That would make a VAST improvement.

http://crevicereamer.com/Page__57.html

CR.

[ger21]

I'm not so sure about running those screws 1:1. They are 1 turn per inch, and they are 1" diameter. That's a lot of inertia, and not much mechanical advantage. I'd still go at least 2:1, and the 3:1 should be fine.
For a little more money, 3 Gecko G201's and a 72 volt supply should give you nearly double the speed of the G540. Speed is proportional to voltage, so even at 48V, you're only getting 60% out of the motors potential.

Another option is to get the G540 and motors that are a better match for them.

[Crevice Reamer]

Oh! I assumed he meant 1" diameter. Yes, if they are 1 TPI then he cannot run 1:1.

Speed morphing G540 plus three 381s and 7.3A 48V PSU would still be a less expensive option than three 201s, 72V PSU and BOB. Sell the 425s.

CR.

[Switcher]

yoopertool,

You realize that ebay package ships from China, & the shipping is $109.90 (I see your in MI)?

That's a total of $649.80

Myself, I would spend my money on something that includes support/help/refund like Ger21 said, Gecko.

How about that slogan:
Please join us, let’s create the glorious future together! lol


.

[Crevice Reamer]

If you really want to go N34:

You could get G540, 48V PSU and drive three $99 Keling KL34H295-43-8A 906s with it.

http://kelinginc.net/SMotorstock.html

CR.

[dertsap]

get some gecko 201 (min) and some 800 oz or better motors , little motors and little drivers wont do it putting a 4 cyl into a school bus .
my table has a travel of roughly 3x5 and I use 2" pitch screws , 1340 oz nema 42 on the x , 770 oz nema 34 on the x z , gecko 201 drives , the rapids are well over 1000 ipm , I keep it to a simple 500 ipm but with that am able to set the accel high so that the dwell of the accel/ decel is basically non existent

[yoopertool]

Thanks for the info. I think that I have decided what I will end up doing. I am sure that I am not getting close to the performance out of my 425's as I could be, so I think that I will keep those for now (until I can afford more). I would be happy getting up to say 200ipm for now, and given that i have a 3:1 reduction on a 1tpi ball screw, I think that I can get it with the 425's. What I think I will do is go ahead with the G201's and a 72V power supply (Per Ger, Thanks). This way if I want to upgrade my motors later I wont have to upgrade my controls again. My only question is, will the improved controls help with torque at all? I am pretty sure that I am not getting all I can out of the 425's with my current set up. Thanks again.

[Crevice Reamer]

The rule of thumb is: Double the voltage, double the power. (At a given RPM)

You will be tripling the power--That should help.

CR.

[yoopertool]

I really appreciate you guys helping me out with this. I wish I had the time to learn more about the electrical side of things, but as an owner of a fairly new business, I feel more like a fireman (putting one fire out as quickly as possible and moving to the next). I am trying to use this rather slow economic time as a time to improve my equipment, building, and quality certification. Needless to say this is keeping me more than busy. Thanks again guys.