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Looks Promising to me.
I may just abandon my home designed board and go with these @ that price. Will still add some current limiting circuitry though.
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Great value stepper drivers Just came across Kitsrus stepper driver boards.
They do a single unipolar board kit - K179 for £10 (uk distributor)
And a single Bipolar Board kit - K158 for £13 (uk distributor prices).
They look really good and effectively the K179 kit is a cmos version of the piker, three kits (components and pcb's) for £30 that has to be good value.
Both kits use IRFZ44 mosfets which are suposed to be able to deliver upto 6A
Check out www.kitsrus.com in the US
http://www.quasarelectronics.com/index.htm in the UK
Please guys with the KNOW give me some feedback
Looks Promising to me.
I may just abandon my home designed board and go with these @ that price. Will still add some current limiting circuitry though.
Come on Guys, 98 views and nobody to comment on what I think are great bargains for driving your motors.
It is cheap indeed, but it is also nothing more than a piker. You'll need to buy additional power resistors to allow a higher supply voltage for some speed. These resistors are not cheap while this solution still doesn't perform as good as a "real" chopper drive.
A chopper drive costs more but draws less power from your supply due to (much) better efficiency. You can end up with a much smaller and cheaper power supply compensating for the cost of the choppers. If 2.5 Amps is sufficient the xylotex boards could be a good alternative at 40$.
regards,
John
I know that these boards are not all singing and dancing but for a first machine using the KISS principle (keep it simple stupid) I think they are a great deal.
The three boards with components are about the same price as the piker PCB.
50W aluminium housed resistors at £2.55 each from RS is'nt too bad, either.
Actually the Xylotex 3 Axis, 2.5A, PWM (chopper) Full, Half, Quarter, & Eigth step/Full Step, board is currently on sale for $125US. More flexability, no resistors necessary... and one board, KISS. So far its the best bang for the bux I've seen. I'm considering getting one for my next next project.
mike
Too many projects.
umrk,
Maybe its a good idea to get 3 seperate single axis boards. The total price is the same but if one blows its easyer to replace. Also, if you are good with electronics you can build them yourself with PCBs from thsengineering.com. I have played with a homemade PCB containing the same driver-IC (A3977) and it works quite well. These ICs are less than 6$ each! Lots of power and speed. Not as smooth as more professional drivers (such as geckos) though. But as you said, probably best bang for the buck right now.
greetings,
John
The unipolar driver board K179 is only $9.95 from http://www.alltronics.com/kits3.htm
times 3 = $29.85 all you need is some resistors and you have a 3 axis driver board for less than $50
Maybe that's too cheap !!!
Hi John.
I agree that 3 boards is better for fast/less expensive swapout. A spare board would only be $40, great if you have something(s) you need to get made fast, blow a board and have a fairly tight budget. OTOH a single board minimizes interconnect wiring and theres no need for a breakout board (not that one is required), which is better suited for people with less wiring experience, and better complies with the KISS method for initial assembly. Personal preference, and like the other aspects of CNC, size, speed, software, stepper or servo, cost to build... everyone should choose what suite their needs the best.
mike
The K179 is interesting, and a very good price. Its output mosfet's are rated at abt 13-14A, but of course you'd need to heatsink them well to get even close to that. As shown I'd estimate abt 1-2 Amp max, but with fan forced cooling using a small computer fan 3A might be possible, but then I have little experience with mosfet's. Its schematic doesn't show reverse emf blocking diodes, and at the 250V rating of the mosfet's they may not be required, but I'd rather add them to be on the safe side. Inductive kickback from larger steppers might still take them out.
That could end up being the bang for the bux leader, but of course you'd be limited to full step only, and I wonder what its max step rate is.
mike
Looking at the circuit, the max step rate of the K179 should be more than hundreds of kHz, so no problem there. Also the MOSfets have internal reverse diodes (body diode) which are designed to withstand large currents. This saves one diode per phase, but its still best to have a diode from output to supply, to make sure the max voltage for the MOST is never exceeded. Indeed, at 250V rating that might not be necessary. The total price of the kit is less than what you would pay for the components alone so yes this is a good deal. It all depends on what you look for in a driver. To me microstepping is important because I use crappy steppers that resonate al over the place. Fullstep is almost undoable and even in halfstep mode there are distinct and severe resonant frequenties that sometimes make it miss steps. Microstepping eliminates this and makes the motors move so much quiter and smoother over the whole frequency range. Further I want to keep the driver modular and small. I have three steppers of 10W each. They are rated at 4V but to get some speed I need to have some 30V supply. This can be done by adding powerresistors but at a dramatic decrease of efficiency: Current stays the same while voltage is 7.5 times higher, so Power is also 7.5 times higher. This means that I'd need a 7.5x30W= 225Watt powersupply, while 195W is dissipated in useless heat! In a chopperdrive the supply current drops as the voltage is increased, maintaining some 80-90 percent efficiency. I have a small 36W transformer that supplies all 3 steppers with plenty of oomph. If you have a big transformer lying around this might not be an argument so it all depents on what you want. I agree with xairflyer that the K179 could be a good starter kit to build your first machine or experiment with. Its cheap, easy and probably almost indestructible. A chopper is a lot easyer to kill, but will give you so much more performance...
Just my 2 eurocents,
John
Thanks Limbo
This is the sort of reply I was looking for and explains it all well.
I never knew that these other boards apart from having a chopping circuit had other benifits like microstepping which seems to be a good feature.
The piker board seems to be used a good bit as recomended by Crankorgan.
These boards are basicly the same thing except you get the components and all for the price of the piker pcb.
Does anyone have any experience with the NC Step board.
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