ABB ACS301 repair - progress report

Well, despite the lack of schematic / service manual / help from ABB, I now have a nice new blue-lit LCD (tarty eh?) and access to the programming :)

After unsoldering the jack to the programmer from the top board, buzzing tracks out and remaking all the solder joints nearby, I looked closely at the jack itself and discovered one of the spring contact pins had bent flat (presumably when the programmer panel tried to occupy the same space during the "drop test") and lodged in a notch in the moulding (notch for what? Pass!), a tweak with a spring hook and I had power to the programmer, an added 100-Ohm SMD resistor and a couple of jumpers to the DC + and 0v lines on the replacement LCD module (£2 inc. shipping, Chinese MC1601a equivalent) and it lit up a pretty pale blue colour. Looks much more modern than the original slime green LCD :) I may have to paint it up, now...

I am chuffed, but it rubs in "Check the physical layer first!"

Now to find out where SWMBO has tidied (or hoovered) all the tiny screws to hold the programmer together, and work out how to hide it in the lathe base along with a braking resistor[1]... After I celebrate with a nice warm English beer.

Thanks to all for their input,

Dave H.

I'll certainly look into that some more - after a thorough read of the user manual I was none the wiser, but judging by the ABB braking resistor quick-start guide I found on t'web, I will need a 32 Ohm, 2KW continuous /

12KW peak rated resistor if I want "heavy-duty" braking on a 3HP motor - this suggests to me that it'll be expensive as an ABB item, so I may build it myself with a rackful of 1KW halogen elements - they're about 60 Ohms each, so a bunch of pairs in series/parallel (3x3?) should handle the peak power dissipation and would have the advantage that the applied voltage will be divided across 'em and stay below their 240V rating - should warm the shed up nicely, too :)

I did some back-of-a-spreadsheet calculations, it looks like 12KW peak would give me a brake-to-stop of under 1/2 second at 1500 RPM - that would be pretty hard on the lathe, though! More appropriate would be a dead stop (1/10 sec, under a quarter-turn) at 120 RPM at the end of a threading pass, much less stressful but still pretty quick considering a big chuck and workpiece?

I am, of course, aware this may be wrong, so any advice will be very welcome!

Dave H.

And calculate based on the cold resistance -- it will take a while for the halogen heater elements to get hot enough to reach operating temperature and resistance.

Good Luck, DoN.

Congrats.. persistence and attention to detail have their rewards.

Some folks use a combination of heating elements for power loads. The LERs (light emitting resistors) you comment on will likely work just as well as the dark ones.

Kitchen cooking oven elements have been reported to be good loads, so there are many varieties of cooking-type elements that may be suitable. It may sound a bit over the top, but some power load resistors are submerged in mineral oil.

Cautious on the light bulb replacements - the cold current is about 10x that of the hot current. They get so hot as compared to resistors - the thermo-resistance curve isn't linear.

Mart> "BobH" wrote...