BP Boss Stepper Driver - Gecko or Keling?

[HawkJET]

I would likely have some interest in the motors.

Okay, I'll let you know when they are available. I don't know when I will have the new motors installed though... my machine is working as is and I have a lot of other stuff to do (I'll bet you can relate).

I removed the motor and it is seized.

Got it.

The actual motors might be identical, but the housings (fins) are different

The BOSS 3 has fins that are parallel with the motor face and subsequent BOSS versions have radial fins (perpendicular to the motor face). The motors should be the same.

[bottleworks]

I know this is a little late, but I finished a Bridgeport Series 1 CNC conversion a bit ago.... I used the Gecko 203v drivers with great success. Set to 7 amp output. 72VDC @ 20amp power supply. The motors do get somewhat warm despite the heatsinks. I have reliable 120 IPM rapids. (and to clarify, I've never tried any faster. I'm happy with 120 IPM, and I don't have the free time to play around). The machine is in a production environment...Used 7 days a week, all day. For the heatsinks for the drives, I cut down some of the original control's heatsink and machined it flat for the drives to mount on. I really believe that calling the Gecko drives "hobbyist" is far off base with reality.

[hdokes]

HawkJET, can you divulge what model compumotor drivers you are using? I am now a proud owner of a Bridgeport Series II CNC with BOSS 6 controls. The mill was owned by the Navy and has been sitting in moth balls for years. After re-wiring it from 460 3 phase to 230 3 phase and identifying shortcomings in control wiring and correcting (I was fortunate enough to get a complete set of electrical schematics with it but no BOSS control schematics), and figuring out how to wire a 9 pin D Type connector and attaching my notebook to it I have successfully been able to exercise all aspects of the mill with no issues. Pretty tickled bout that.... in fact... nearly cried like a little girl with joy. I have a couple of break out boards on the way and do intend to eventually swap the legacy drivers with new ones but am happy to run with the old ones for now. I would like to know which model of compumotor drivers you went with for the legacy steppers. Can the break out board be wired in to the existing BOSS control drivers? All outputs are opto isolated on the break out boards. Not having a set of BOSS 6 schematics I am unsure if it can be done or not.

I go way back to the 80's with compumotor. Actually didn't know they were still in business. In fact, I still have one of the original programmable linear stepper slides and controllers from that era.

[HawkJET]

HawkJET, can you divulge what model compumotor drivers you are using?

I have a dozen ZETA 4 drives on the shelf and so I used them. Since they are 4 amp drivers, I modified them with new (modern) MOSFETs and changed the current feedback resistors to get more current. The new MOSFETs are lower resistance and can handle the higher current and still run cooler than the originals. If you are handy with a soldering iron, I can walk you through it if you want....

Compumotor ZETA4 drivers can be found on eBay for $100 - $150 from time to time. Check periodically, some sellers want $400 or more.

in fact... nearly cried like a little girl with joy.

I am familiar with that kind of joy!

Can the break out board be wired in to the existing BOSS control drivers?

Several have done just that. I haven't, but one of them may chime in. Hillbilly makes a BOB that works (I understand).

I go way back to the 80's with compumotor. Actually didn't know they were still in business. In fact, I still have one of the original programmable linear stepper slides and controllers from that era.

I too go way back... I was the entire mechanical engineering department for their first two years of existence.

[hdokes]

Thanks for the prompt reply HawkJET. Given it had been a couple months since the last dialogue on this thread I wasn't sure I would get a response for a while... then I seen you were browsing the thread which immediately had my hopes up.

I have a very diverse back ground. A jack of all trades..... pretty darn good at some as I put it. Quite mechanically, electrically, electronically, and programming savy. Been at it in many capacities for more time than I care to admit. Fabricated HVAC fittings and the like at 14, installed Heating and Air Cond. at 16, license electrician at 18, Electronic tech in the Army (with full component level training) at 23 to 27, and cut my teeth on the original Apple ][ plus computers both in programming and the hardware. Spent many years in industrial controls and automation... and now... I am blessed to have a 16,500 sq. ft. facility where I have converted the front office space (2500 sq ft) to living space and the back end (14,000) out my back door has been set up to be a full blown prototyping shop and I couldn't be happier.... well... ok... there's always something that can make a guy happier... another machine... pre-nup agreement... but hey... I have my own urinal in my shop!... so I can't complain!

I will keep a look out for those drives. I am quite handy with a soldering iron. Have the ability to make my own circuit boards and have. I actually have an email into Derek who makes the Hillbilly BOB board but think he has been out of commission for a couple years. No response from him. I did find a schematic for his board and have considered making my own in the event I do not get a response from him. It was important to me to find a BOB that had socketed chips and was fully opto-isolated. I could only find one from china that fit that bill so I ordered two. 5 Axis Breakout Board for Stepper Motor Driver CNC E | eBay . In fact... believe they just came in today. Have to go check. They also have output and input LED indicators on them as well. If I could find a set of BOSS 6 schematics I am quite comfortable in persuing a direct connection of the BOB to the BOSS 6 controls.

I have been a 'voyer' to cnczone for a number of years but only now am getting 'involved'. I hope to continue to be from here forward.

Thanks again HawkJET and look forward to many more conversations with you and the rest of the 'gang'.

[hdokes]

HawkJET, is there a particular model for the Zeta 4 I should be looking for? I have seen them on ebay and some refer to them being a 'servo' drive. Were there servo and stepper variations of this drive?

[HawkJET]

HawkJET, is there a particular model for the Zeta 4 I should be looking for? I have seen them on ebay and some refer to them being a 'servo' drive. Were there servo and stepper variations of this drive?

ZETA drives are stepper drives. There is an auction on eBay right now that incorrectly lists them as 'servo' drives. There are two available from ds_machine for $120 ea.


You can tell by the label on the back of the drive that shows how to set the dip switches....

[hdokes]

Thanks HawkJET. I'll check them out.

[SchortBus]

Been three years, seems time to bump.

Folks having good results with the IM2882 with Sigma Steppers? Own a BOSS, the OEM controls have given up. Been keeping running swapping transistors / diodes and such - not again. Time to finish the upgrade but need something up and going fairly quick.

[BOSS5]

I'm still running my D6's on the BOSS 5, set to 10 microsteps per full step. Rebuilt the controls cabinet last year and now it contains 5 of the Slo-Syn 2000-D6s (rotary axis and knee axis were added). I also switched over to the ESS from warp 9. Much better, the old twin parallel port setup feeding the PDMX 126 board saw glitches every 64 seconds due to the computer's low level background process interfering & being unfixable (an IBM desktop, Pentium 4, windows XP running mach3). I swapped out my three 1850 oz-in rated 3-stack sigma 4288Ds for Pacific Scientific Hybrid motors, E series SIGMAX, 2 stack variety. These were their successors, and are a bolt-in replacement for the original Bridgeport installed hardware, so the shaft and keyway fits perfect to the pulleys. They are rated around 2800 oz-in. I chose these for their microstepping ability. Now I can see actual movement when I command a 1/10th step, before you really could not, or it was so non-linear in response that approximately half a step was all that could be obtained with consistency. The smoothness improved, especially at low speed. The windings are series connected, and I run at the full 6 amps, ~160 volts. I have the X-Y-Z rapids set to 180 IPM, 3 ips squared acceleration, Even tried 220 IPM, it worked fine, but got me too scared ! Was afraid of damaging the belts, which I tensioned more than before in order to get the full microstepping resolution into the table. The powered knee is a nice to have feature. I set that around 60 IPM, though it can go much faster. Both it and the quill axis have 3 stack steppers, and the knee unit is a 4000 oz-in beast in the square bodied K series motors, while the quill is a round bodied sigmax unit like on the X-Y axis. I never need to worry about skipping steps because I'm too close to the limit. In fact I never checked the real limit, mainly out of respect for the mechanicals.
Anyway, with good hardware, speed & smoothness is certainly not an issue anymore. In retrospect, had I simply changed to the smoothstepper from day 1, I'd probably not have gone down the road of twice upgrading the motors on this mill in search for greater speed and smoothness, it alone makes a significant impact on both. The series 2 mill still has its original sigma motors, and may one day see an upgrade too. It normally runs 100 IPM rapids using the D6's and a Planet CNC usb board. No issues there.
I know none of this answers the question of how good is the Leadshine 2282, or any of its many private labeled variants. I only have one unit, tested it and saw no marked difference with the D6's & Compumotor drives (of which I have a dozen or more on the shelf), so expect the same result or better. Reliability of these Asian drives, can't say, nothing to base it on. My D6's, I have never seen a hiccup from them. Bought them all used from various vendors on ebay, cheap. A few of them arrived dead, where-upon I ordered new MOSFETS and fixed them for a few dollars, as it cost less time, money and effort than to ship them back!

Would I use Gecko drives on the Bridgeport? In short, no. Why bother building a separate power supply & filter for these, then a heatsink, when for the same money you can plug & play with a Leadshine that has twice the bus voltage. I keep 3 Gecko's on the shelf, for a space critical application that I planned a long time ago but never got around to building yet, so for that probably OK.

Hope this helps anybody who keeps wondering what to do, the why's and how's. A stepper driven Bridgeport BOSS that performs like a servo machine, yup, its possible.

[Eric]

Hey Boss5,
Can you post the part numbers for the motors? I could not cross the motors with your specs. I didn't see a 2-stack E42 motor with 2800oz in and 6A series rating. I like the fact that they have Nema 42 flanges, 0.625" dia x 2.19" long shafts which match the OEM Boss 5 motors. It looks like the key ways are wider than my original taper-lock bushings, but that is not difficult to change. These sure beats adapter plates and shaft adapters/extensions. Got any pics of them installed?

Thanks.

[BOSS5]

I just checked the catalogs & machine in question.The X&Y use Sigma E42HXLC, rated at 2698 oz-in +/- 10% holding torque @ 7.4 amps phase current. The label on the motor indicates the winding are designed for 160 volts. If you check the generic torque graphs in the catalog you will see that the running torque rises slightly from the initial value, maximizing at about 500 full steps per second, then declining. The initial value is lower than the holding value. For example on the previously installed Sigma 21-4288D200-F03, 1850 oz-in holding, 1480 oz-in running is given for 13.2 Amps Bipolar. (Each phase gets 6.6 amps). The stock Bridgeport motors are Sigma 20-4270D200-F03, 1310 holding, 1090 oz in running at 50 full steps per second. They are rated at 10.6 amps bipolar, 7.5 unipolar. The catalog shows these with a performance curve under bipolar conditions using a 65 volt chopper drive, which was the state of the art for the late 70's early 80's. The machine was designed in 1978 according to the blueprints.The unipolar performance was not given, but a footnotes indicates to expect a 20% reduction on torque. The Bridgeport drives are ~ 56 volts Unipolar, running at 8.2 amps when the drives are holding, and dropping to between 4.6 to 6.0 amps when the machine is in rapid @ 100 IPS. The Superior motors are M112FJ, 1125 oz-in holding torque rated 6.1 Amps per phase unipolar. I believe these were used in the early model BOSS machines, moving to the Sigma motors for later versions, possibly when the cooling fins went from the square design to round.

About fitment, the original taper lock hubs in my machine came with with both 3/32 and 3/16 keyways. So the 3/32 woodruff key (original) and the 3/16 square key (most newer sigma motors) both fit without alterations. On my Z quill axis I have a 3 stack H43HXLB, 2256 oz-on holding, 6.2 amps rated current per phase. It came with the 3/32 woodruff key, so a perfect fit on the aluminum z-axis pulley. The Z knee axis uses a Sigma Powerpac hybrid N43HXLN, rated at 4365 oz-in holding @ 7.7 amps phase current. Like all the other motors, the phases are wired in series to see as close to full rated current as possible [the drives I use put out 6 amps]. The phase resistance and inductances on all these motors are low, but still above the lower threshold recommended by the drive manufacturer, so basically they are well matched to the motors and close to their maximum power is being extracted. Some of the motors have power ratings on the label. Typically these lay between 265 - 320 watts.

As an aside, my knee Z-axis got stuck in the far down position (motor stalled when trying to raise) because the jib was set slightly too tight, and it never sees any real use in this position. When I was trying to figure out what the issue was, I inadvertently discovered that the 50% current reduction feature on my drives was turning on during movements (not off as it should be) due to a software setting mistake. So I'd done all the previous axis tuning on half current ! I was OK with the way the machine felt at 180 IPS rapids, and even had it well above 200 (gets scary). This was all done at half current (3 amps) as I now realized. Wow! Enough said.

[Eric]

BOSS5...thanks for the great posts. This will help other's in the future. I just checked my keyways on the motors that I have (both square and round heatsinks) and they are 3/32. These were from a Boss 4. I did not check my Boss 5 pulleys so they may be different than the Boss 4 that I have apart right now.

Where did you find the part numbers and specs on the original Bridgeport motors? That is great. However, I can't really find any info on the net about them while searching for the OEM catalogs and specs. Is there any chance you have the OEM catalogs for these and if so, can you PM it to me?

[BOSS5]

Bridgeport did not publish motor specs to my knowledge, but the service manuals and build commissioning sheet lists electrical tuning parameters when the machine shipped out. I have all the old stepper motor catalogues from various manufacturers spanning 70's to 90's, so it was easy enough to match up the motors from physical dimensions and phase resistance and impedance measurements. I have the test equipment to do that, so pretty straight forward. There is but one "fit" for each of Sigma, and Slosyn brands in the catalogs. They were produced over many years. I have a few of these original units now as spares sitting on my shelves. They are just off the shelf items from that era. You can find them all on ebay these days. The various catalogues have hundreds of pages combined, so I'll not be scanning any of that (for anybody). I just put the basic info out there for people who want to do something similar, and wonder about the performance levels to expect. Many have adapted metric shaft steppers from Asia, along with the drives. Scan the build threads in this forum. You can always bore an existing taper-lock bushing, make a new key slot, etc. Just its a bit easier and cheaper when you find exactly what you are looking for. On the new steppers, I did helicoil the mounting holes on the flange (5/16-UNC) to accept the original cap screws that hold the motors in place. Easy enough.
From the electrical standpoint, be sure you understand the motor specs well. Rated current per phase is tricky. In bipolar parallel it will be double the series rating, and root 2 times the series rating for unipolar. Each produces the same heat level. For example: The Sigma E42HXLC has 8 terminals. In Bipolar parallel you need 14.7 amps to drive it, Series requires 7.4 amps, and Unipolar 10.4 amps. The corresponding phase inductances are 2.7, 10.6 and 2.7 mH respectively when you hook them up these 3 different ways. As you know, finding a modern driver that outputs more than 7 amps is difficult, so the way to go is series wiring generally speaking - along with high voltage. In series each winding sees about 80 volts (160 DC bus voltage is spread across the two windings). If you wire parallel, then the same 7 amp driver puts only 3.5 Amps into each winding, hence low end torque is cut in half, although you may still get adequate speed if the driver is outputting 80 volts, as each winding sees the 80 volts in this case. You have to watch the impedance, for example the SS2000-D6 is designed for 10 mH or more, the Compumotor S-6 units can drive as low as 2 mH, but they recommend going higher, around 5 - 50. Basically the lower the value, the more current the motor draws at high speed. Big motors with low resistance windings draw huge currents already, and also have low impedance to boot, so they can overheat your driver. Of course these motors are desirable because they produce greater torque at low speed, whereas a low current drawing motor will not, however the later have somewhat better characteristics at high speed. So the combo of driver and motor is important to achieve a good result. For each motor frame size and stack number, there are various winding options to choose from, and as explained above, different ways to hook them up. Also, you can get Sigmax, and Standard magnetics in the rotors. Then there are the Power Pack (square) and conventional, low cogging torque, encoder mount options, special shafts, mill std connections, different keyways, the list of options is long. Buying used, you take something that is close enough and make it work. That's what I did. Hope it clears the remaining mysteries. If not, re-read some old threads.