Bridgeport Series 1 steppers - replacement

[Mr. Technical]

I'm doing a retrofit too. Finally got tired of one of the original (Superior I think) motors randomly deciding to quit for a minute, while the other axes keep doing their thing, resulting in ruined parts and crashes.

I'm looking at the Keling Nema 34 motors, that have 1200 oz/in of torque, namely the KL34H2120-42-8B (Dual shaft with flat) Rated Current: 6A, Rated Voltage: 3.5V (in Bipolar Parallel). If the original steppers were only 800 oz/in's of torque, they should be a nice upgrade.

I'm looking for info on the original steppers though. Anyone know the dimensions on them (shaft diameter, hole spacing, mount plate size? I won't be able to pull them off the mill for a while, but would like to get going ordering parts. Thanks, and I'll be interested in hearing how things go for everyone else doing something similar.

[Mr. Technical]

Hey Jking, would you mind sharing what model of steppers you got from Keling? Also, what you had to do to get the smaller motors to fit? Feel free to contact me directly if you're worried about derailing this thread. Thanks!

Ian

[dynamotive]

I've had a Bridgeport Series I for many years, and gotten a lot of good use out of it. But the Boss 5 controller just started getting flaky, and I think it must be retrofit time. The stock motors seem ok. If I use Gecko drives, which ones should I use? Any reason not to use the Boss 5 power supply? Does anybody have an actual wiring diagram?

I've noticed several mentions of Keling, and I had a very good experience with him, getting a drive for a rotary table - he was the only one to actually give me a list of parts to get, and he answered my questions about wiring. Any reason not to use his drivers? I suppose if I sell the machine it sounds better to say it has Gecko drivers.

[Mr. Technical]

Hi dynamotive,

There may be another option that I don't know if you've considered. You say that the controller is getting flaky on your mill. I had the same problem with my Series I. I got a great breakout board from Hillbilly, who's a member on these forums. ( http://home.icx.net/~ashburn/index.html ) That allowed me to remove all of the original edge connector control boards in the the control cabinet, as well as the DC power supply, and replace them with a computer running his breakout board. It has worked well for a couple of years now.

If you are having problems with the drivers blowing transistors regularly, the Geckos would definitely be a good idea. He's got some great products, and is very involved in technical support. I built a driver board using Gecko 203Vs, which are the latest stepper drivers from Mariss, and are said to be virtually unkillable. I've still got the stock motors on there. (Sigmas, not Superior, but both work with Geckos) If you go that route, use a current limit resistor on the Geckos to 6Amps.

As far as the power supply, many have used the existing transformers, which I think are rated at 56VAC. The Geckos can handle up to 80VDC and 7A. You might think that you could use a transformer rated to a higher AC voltage, but 56VAC is converted to approximately 77.68 VDC after rectification, filtering etc.

( DC Output Voltage =[ (AC Input Voltage) * 1.414]-1.5 )

I highly recommend a power conditioning board from the guys over at PMDX. (http://www.pmdx.com/PowerModules) I'm using the PMDX-135-8020 which handles plenty of current, and has some nice extra features built in. All you do is connect the transformer to one side, and the Geckos to the other. Couldn't be easier, and there's a schematic for connecting the power conditioning board in the PDF user's manual on the PMDX site.

If you do go with Geckos, you'll need a breakout board (Hillbilly or other), transformer (salvaged original), power conditioning board (PMDX), and not much else. Hope this helps!

Ian

[rogerfries]

I use the Hillbilly Breakout board and retained the stock BOSS 5 stepper motor driver boards. Works great! I use a Windows Box with Mach 3.

If you are blowing transistors, make sure that if you are using a phase converter that the artificial leg is on L3! Very important that L1 & L2 have clean voltage.

[dynamotive]

Ian:

Thanks for the great reply. You say that you got a breakout board that allowed you to remove all of the original edge connector control boards in the control cabinet, as well as the DC power supply, and replace them with a computer running his breakout board? Does that mean you were still using the existing drivers? That’s interesting. I hadn’t thought of that possibility. I used to have the problem of blowing power transistors, particularly when I started the spindle. As a matter fact I changed the transistor heat sink boards so that the transistors are plugged into sockets, and facing outwards, so they could be changed easily. But, somebody on cnczone said that I probably had my rotary phase converter hooked up wrong, with the manufactured phase on one side of the spindle drive, which is driven by L1 and L2. Since I changed it, so the 3rd phase was on L3, I haven’t had any transistor problems.

Why did you use a different power supply?

My problem right now is the dreaded 70007 error code. I just checked the logic voltages, and there is a serious problem there. Here’s what I got from the test points, top to bottom, with the digital voltmeter black lead in the GND jack:

-12 UR 17.27 (positive, not negative)
-12 R -12.02
+12 UR 27.2
+12 R 12.03
GND +12 -.037
+5 UR 14.54
+5 R 4.98
GND +5 -.078

So, obviously, the UR part is screwed up. Anybody have any quick fixes, or things I should look at? I checked all the fuses in the logic cabinet, but they all seem ok.

[mactec54]

Hi Dynamotive

If your power supply is bad I may have one if it is the same as yours Post a photo of it & I will be able to see is your machine a Boss 5

[dynamotive]

Yes, it's a Boss 5.