Danfoss s1000 DC Motor speed controller - help needed!

[HankMcSpank]

I posted the following on a UK CNC forum, but what with the board being a Danfoss, I guess I'm likely to have more luck here...


My mini lathe had a bright flash from the control box - now not workee! The board is a Danfoss s100 -often rebadged...varispeed seems to be a constant when rebadged)


For an output stage, the circuit has S6060L SCRs & 3 D6020L Diodes.
I'm ideally after the schematic for the Danfoss S1000 (I have the user manual but it doesn't go into schematic detail)

Failing that, would anyone have a suitable similar circuit so I can establish how this implementation works? I'm told by someone well versed that this board is likely to be a "full-wave half controlled bridge (2 diodes, 2 SCR arranged as a bridge rectifier) the third diode is a snubber across the motor"





(those thee ICs are 2 x LM324 & 1 X LM339)

[HankMcSpank]

I've scoured the web, but no luck - does anyone have a 'standard issue' DC speed controller schematic that may be similar (just to give me a 'vibe' of how they're likely using the LM339 comparator and LM324 opamp)

Once again, this is a DC Speed controller using a couple of SCRs (I presume to get a variable rough & ready DC level for the motor from a mains AC input)

[Al_The_Man]

This is the same set up used in KB and Baldor small DC SCR drives, if you are 'lucky' it is just the bridge components that are blown.
As you guessed, these are a bridge with 2 SCR's and 2 power diodes with one as a snubber.
If it does not appear that anything else is blown, you could just change out the power devices.
In one case, I fitted higher power devices on a separate heatsink.
Al.

[HankMcSpank]

Alas, I don't think it's the output silicon that has gone here....I whipped out the SCRs & they checked out fine. there are two low voltage regulators (a 78L08 & A 79L08), both blown (I think some swarf might have got into the control box, as there was a flash while I was using the lathe!)...they might have taken out the opamps/compartor, so I'm reluctant to just replace the regulators until I've had a look at a similar setup. You mention KB And Baldor - is that one company? (as in "KB & Baldor") or are they two different companies - if so, what is the KB short for?!

Have you any of KB &/or Baldor's board model names/numbers that spring to mind to help me on a hunt for a schematic?

Many thanks!

Edit: Actually a Baldor DC3N motor drive on page 28 of their catalogue looks fairly similar to my Danfoss S1000...

http://www.baldor.com/pdf/501_Catalog/Section19_DC.pdf

that sorts the Baldor - but who are KB?!!!

[Al_The_Man]

I believe KB are the principal manuf. and the Baldor are re-labelled version,
http://www.kbelectronics.com/
Side by side they appear identical.
Al.

[techrat]

If you are still having problems with your board, I have 2 Danfoss S1000 boards that I would be willing to part with. Send me a PM if you are interested and we can work out a price/shipping.