[Walky]

Put shortly:

- The G540 can provide a max of 3.5A to a motor

- If a motor rated current is less than 3.5A you NEED to use current set resistors to make the G540 provide less current to the motors (otherwise you can kill them). Connect them at the G540 side, not the motor side!.

- A current set resistor is nothing more than a reference value to indicate the G540 what current to provide to each motor. e.g. 3.2K Ohm resistor sets the G540 at 3.2A.

- If no resistor is installed, the G540 will provide the most current it can (3.5A), for 3.5A and higher motors it's OK, but can kill motors with lower rated current (as mentioned earlier). The problem is, if no resistor is installed there's no current reduction. If aiming for a 3.5A resistor, I've read it's a good idea to use a slightly lower value resistor (also consider the resistor tolerance to make sure it's under 3.5K, or get a bunch of 3.48K, 1% tolerance resistors and use the ones with the lower measured values); IIRC, current reduction won't work with resistors over 3.5K (I could be wrong about this).

- Current reduction is a method the G540 uses to prevent unnecessary motor heat by reducing the current going into them when they're not active. Some stepper motors can get really hot near full current so it's a good idea to have the current resistor in place.

[Bob La Londe]

I have bought a couple "kits" and misc parts, individual motors, etc from Ahren at CNCROUTERPARTS.com, and I have been satisfied with the service.

[Pplug]

Thanks drools,

I'm glad someone could help me....So, in my case would it be better for me to run the motors without resistors? Those motors are 3.5a max., what would you suggest? Since my machine will be similar to yours....BTW how's your machine w/ 620oz-in motors and 3k resistors?

dinky,

You want to use the resistors still because with the resistors the drive will cut the power to the drive in half when it is motionless. This is desirable because it will help keep the motors cooler and help keep the g540 cooler as well. Those motors do get very hot!

[dinkyguitar]

Thanks again guys!!

I really appreciate all your feedback!

dinky,

[msimpson99]

The bottom line.
If you want plug and play, buy the cncrouterparts kits. They are the only ones I recomend in my KRMx01 and KRMx02 books.
I have four of the kits, and run them night and day.

[Bob La Londe]

Thanks LazerBee,

Your not being mean....I just didn't understand what the resistors were for, so I asked questions to someone who supposed to deal with them and they didn't answer me, as if they didn't know...Now granted they may be getting hundred's of emails, but I didn't feel confident in them.

Anyway, with the help of the members on this forum, I got my questions answered...



dinky,

Keling has some great products, but I also found they often do not answer the question asked. Often their answers were along the lines of, "You can buys our product here," which of course is totally unhelpful. In addition I once had them tell me a particular product would work with another product via ebay messages, and then when I called them out about it here on cnczone they said it wasn't compatible. Of course I cut and pasted their message reply as a response. Now do not get me wrong. Keling has some great products, but they are not big on support. You need to do your own research and look at their documentation on the products before pulling the trigger.

The best place to ask beginner questions as you have found is HERE on CNC Zone. I ask "dumb" beginner questions here all the time.

I don't have much fear about mixing and matching these days, but I wouldn't hesitate to buy a motors and controller kit from Ahren at www.cncrouterparts.com if I needed to get a machine working quick.

[ahren]

Hey all,

Just found this thread. First of all, thanks very much for the recommendations for our products! I think you guys have it all sorted out, but just in case I wanted to clear up any confusion about the cables and motors we offer.

Both our motors and cables have 3.4k resistors across pins 1 and 5, and these are overmolded into the male connector ends. This is so that you can plug a motor directly into the G540, or through one of our extension cables and get the standby current reduction. The resistors are not doubled in this case, as only conductors 6, 7, 8, and 9 are carried through.

On our older cables, we did carry 6 conductors through, including those on pins 1 and 5, and relied only on the current set resistor in the motors -- this seemed logical, as it allowed the motor to set it's current value. However, some G540's experienced noise issues with this configuration due to the long inductive pickup of these conductors, so we have since gone to cables that have the current set resistor at the drive end. The black adapter cables people are referring to were created to help out people with G540's that had issues with noise, and are effectively really short versions of our new cables.

So there you have it. Our cables are not communications cables, but are custom made for us. They feature the current set resistor on the drive side, a grounded foil shield, and 20 AWG conductors with super fine stranding for flexibility -- you can see a picture on our website.

CNC Motor Cable | CNCRouterParts

Best regards,

Ahren
CNCRouterParts

[met4life]

Sorry to revive this thread but I came across another site and was wondering if anyone had dealt with them. The product & description are exactly as that on CNCRouterParts.com but $50 cheaper.

3 Axis Electronics Kit : Fine Line Automation

They appear to be having a Black Friday sale too!

"For those thinking about buying a kit, we will be having a Black Friday sale again this year! $200 off any kit and $75 off all electronics kits. Sale will start at Midnight the Friday after Thanksgiving and go through Monday. We have many kits in stock for immediate shipment."

[kinghong1970]

seems there's quite a bit of unhappy customers in service and response when dealing with FLA...
i ordered 2 items and i did eventually receive them... but no info on tracking, no info on when it shipped, no reply to emails...

cncrp, as many stated, can't be beat... ahren is wonderful to deal with.

[ger21]

While FLA has notoriously slow communication and shipping, every person I've ever seen order from them did get their products.
And yes, a lot of what they sell does come from CNC Router Parts.
$50 is $50.

[Lee DeRaud]

What tends to get lost in the noise is that, at the DIY level, this is very much a cottage industry. The quality of the product line doesn't necessarily carry through to the level of service and support because the vendors simply don't have the kind of infrastructure that mainstream commercial sites do. I don't know about FLA in particular, but if you're dealing with a vendor where the the guy answering the 800 number is also the owner, you may need to adjust your expectations.

[Bob La Londe]

Sorry to revive this thread but I came across another site and was wondering if anyone had dealt with them. The product & description are exactly as that on CNCRouterParts.com but $50 cheaper.

3 Axis Electronics Kit : Fine Line Automation

They appear to be having a Black Friday sale too!

"For those thinking about buying a kit, we will be having a Black Friday sale again this year! $200 off any kit and $75 off all electronics kits. Sale will start at Midnight the Friday after Thanksgiving and go through Monday. We have many kits in stock for immediate shipment."

I have purchased from Ahren Johnson (CNCRouterParts.com) atleast 3 times, and never had any issues. I have also reccomended his motor and controller kits to three diffferent people who used them to build their own machines. None have come back to me with any issues.