Reply with Quote120 AC gets rectified to ~ 170DC minus losses, so effective 160 volts available at the DC bus. This is what you need, choose the KL-11080, forget all the other stuff. Use the half-current function to let the motor cool when idle.
BP Boss Stepper Driver - Gecko or Keling?
I just got my BP Boss 5 and want to use the original steppers for now to save some coin. I had originally decided to use Gecko 203v's like most have but I came across some of the offerings from Keling...specifically the KL-9082 and the KL-11080. I'm wondering can they give me anymore speed/torque while staying with the original BP steppers versus the Gecko drives?
Here's a link to the Kelings:
KL-9082 Bipolar Stepper Motor Driver 24-80VDC 8.2A | Automation Technology Inc
KL-11080 8 Amp Bipolar Stepper Motor Driver | Automation Technology Inc
Looks like they put out a little more power. Any disadvantages to using these over the Geckos? I see the KL-11080 also doesn't need a power supply as they have on built in.
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120 AC gets rectified to ~ 170DC minus losses, so effective 160 volts available at the DC bus. This is what you need, choose the KL-11080, forget all the other stuff. Use the half-current function to let the motor cool when idle.
Was reading the other thread. You mentioned the DM2282. Would that be an even better choice? Those look sweet. I like being able to run 220 to everything.
Or a Slo-Syn S2000D6? I guess neither are programmable. Does that really make much of a difference?
Right now I'm running the SS-D6, they are fine, older tech, but bulletproof. The compumotor S6 & S8 are more advanced, with extra tuneable damping features. I just ordered a DM2280 to play with. I suspect it will be better in terms of smoothness. Playing with the tuning software will be a new experience. The 2280's bus voltage can be higher if you power it with 220V, so you should be able to get lots of speed. Where I live the line voltage is about 240V, so I'm worried the drive will fault on overvoltage. But you can also run it on 120V. Going line to line from a 3 phase 208V service should be fine however, but I don't have that at home. With the 3 stack motors I've installed on my bridgeport I can run well past 200 IPM, but typically I don't, it just gets a bit too nerve wracking to watch. 180 IPM rapids are where I keep it mostly, but at times I set it back to 120 IPM or 90 IPM, especially when trying out a new program in an attempt to avoid crashes.
That's with stock steppers? Wow. I'm glad I found these. This is going to save me a lot of time. I see the Leadshines do have the software tuning which is cool. Not sure if I will ever need it but good to know it's there. I'm just happy I found a drive that can actually power the steppers right and actually has all kinds of new technology.
I don't have three phase either. Will probably feed 220 into the machine and run everything off there.
Let me know how you make out when you get to trying them. I'm just starting my conversion tomorrow so it will be about a week until I get to the drives. Thanks for the input.
I have a few different Bridgeport BOSS mills. Stock motors are Sigma 20-4270D (double stack) with about 1300 oz-in holding torque , around 1000 running. I bolted some 21-4288D (3 stack) rated for 1850 oz-in holding, 1450 oz-in running torque onto my series 1 machine, so it is the quicker one. The series 2 Bridgeport runs 140 IPM on the stock motors. All machines run SS-D6 drives at the moment. The pulley ratio is 1:1 on the series 1 (Boss5), and 2:1 on the series 2 (Boss6), so the results will vary a little. The series 2 machine does 140 IPM.
Nice. Any idea how much power those Leadshines draw? I will be running them at 8.2 amps but is that actually 8.2 amps at 110v or 220v (depending on how I wire them)? I can't find anywhere in their documentation where it states that. If that's the case and I run 3, or 4 drives, that's a lot of power. Would also have my spindle running too so I would need to plan for the feed for all that if that's the case. Would be 24.6A at 220 for 3 axis....seems like a lot assuming all three are moving at the same time.
Boss 5
Was just looking on ebay at the SS2000D6's and there are some deals to be had. Might just got that route and save a few bucks. Doesn't look like they come with the wiring harnesses though and they are stupid expensive. Any way around using the original harness? Maybe a common plug that fits in there?
The SS-D6 is rated at 7 amps, and it contains an 8 amp fuse. There is alot of reactive power (poor power factor) in these drives. I have my 3 units all tied together on a 15 amp circuit and have never seen a problem. I suspect the Leadshines draw the same, perhaps a bit less. The 8.2 amps means nothing, the RMS value of 5.9 amps divided by the efficiency of the power electronics would indicate something likely under 7 amps.
What wiring harness? It has screw terminals for the motor, and they usually they come with a plug-in screw terminal adaptor for the controls side. If this last item was removed, it is a $15 dollar item to replace via digikey.
Gotcha thanks. Trying to figure what size power wire to run. My VFD already puts me at 10 awhile so another 15 amps is gonna be pricey.
Ya figured it was something common. The manufacturer replacement cable was like $240.
Debating whether to spend the extra $150-200 on the Leadshines. I will probably do it just for the fact its newer technology and less heat on the motors. Plus the software tuning is a bonus.
Thanks again.
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Boss 5 -- If I go with the Leadshines and run it 220 isn't that going to yield about 300 volts DC? I know the amps will be limited by the drive and speed is a function of voltage where as torque is a function of amperage. Is that too much juice and will it make the drives overheat or is that just available power and whatever IPM I decide to run them at will determine the actual voltage the drive sees?
Confused here a little...don't want to blow up my motors. Guess my questions is does voltage make drives overheat or amps or a combination of both and can I run those older motors at 220 or should I wire them 110?
If you do not set the driver for more amps than the motor is intended for, the only way to overheat the motor is to turn it too fast. Motor heat is a function of POWER. Power is torque times PRM times a constant (depending on units). Current determines the motor torque and Voltage determines how fast you can turn the motor.Originally Posted by jonesturf
So keep the current to the motor spec and moderate your rapid speed, you should be fine.
"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." Antoine de Saint-Exupery (1900 - 1944)
Ok makes sense. I read over again the stepper basics from Gecko and other sites explaining that max voltage is 32 * sq rt L and all that stuff. Hard to find real numbers for the original steppers but I did find something I think may be valid. It's well below 110AC/154DC either way which makes me a little apprehensive to pull the trigger on a bigger driver.
According to what you said just so I understand right lets say I a power supply that uses 110AC/154DC and maybe that maxed out would get my 250IPM but overheat at that rate. If I keep it down to 100IPM in rapids then it's really not reaching the POWER that it would be like at said 154DC thus it wouldn't overheat? Is it still seeing the 154v or is it getting less with the rapid turned down?
I'm assuming the drive is a constant current power supply so the voltage varies with speed?? That's my big question which I really haven't seen the answer to. If that's the case then it just has extra power but it doesn't have to use it and I shouldn't fry my motors, right? I'm really not looking for ridiculous speeds...I know the limitations of these motors. I want to take advantage of better technology (digital tuning) and get a drive that has a built in heatsink and power supply. In the future if I want to update my motors I also have a good drive to build off of.
Yes, you got the jist of it.
It's not that simple... The inductance of the motor limits how rapidly the current can go from zero to max. The higher the voltage, the faster the current can rise.
To rotate the motor, you energize one phase and then the other, etc.,etc. At a given RPM, each phase is on for a finite amount of time. If that time is too short for the current to rise to maximum, the torque will drop off. Increasing the voltage increases the RPM that this occurs.
The motor driver is a current source until the above condition is reached, and after that, it is a voltage source.
This is a rule of thumb that is intended to keep the motor from overheating. If you use more voltage than is allowed by the formula, you are in danger of overheating the motor. However, if you monitor the heat, or provide other methods of removing the heat, you can exceed the voltage given.
There are very good reasons for the rule, so violate it at your own risk....
Last edited by HawkJET; 02-08-2014 at 09:45 PM.
"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." Antoine de Saint-Exupery (1900 - 1944)
So it seems BP originally wired the stock motor unipolar with 56v to each winding at 8.2A. If I ran it with 120v AC/168v DC in series then the motors would see 84v in each winding and the current would be at 6A. That seems correct, right?
The 84v should stay within the equation for determining overheating from the specs I've come across. If I did that right then running a Slo-Syn or Leadshine 120v AC drive shouldn't be an issue, right?
You are over-thinking this. My suggestion is to wire it as shown here:
http://www.cnczone.com/forums/bridge...tml#post803301
And go make chips. The BOSS machines have gargantuan heat sinks that are terminal overkill. Mine have never been remotely warm. You will be just fine. Above I mentioned that one could exceed the "rule-of-thumb" if one removed the heat.... The Bridgeport heat sinks do just that.
"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." Antoine de Saint-Exupery (1900 - 1944)
I tend to do that when making important decisions. Thanks for the input. I figured the heatsinks were what you were talking about. Just not a lot of info of people using anything other than Geckos.
I hope you didn't take it as an insult. It wasn't. I merely wanted you to know it isn't real complicated.
I understand, and agree. I am very happy I went with higher voltage drivers. It simplifies the installation and saves the expense of the power supply. I also found drivers that were cheaper than Geckos on eBay.
FYI - I use Compumotor drivers set at 6 Amps. I experimented with higher current but the 6 Amps gave me the best performance. I surmised that the higher current levels affected resonance and reduced the maximum velocity.
"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." Antoine de Saint-Exupery (1900 - 1944)
