Oatley K25 PWM kit - feedback and questions

Mine worked OK, and is still working. What are you driving with it?

Colin

Will be driving a 350W scooter motor - tried with just a multimeter across the output - volts ranged from 0.6VDC at the low end, then up to

23.5 - 24.0 VDC at the "fast" end. ("End" is relative to the step at the 10degree travel mark.)

With the motor connected, the motor is stationary at the low end, and flat out at the higher end.

I did have a 6800uF electro cap across the output for smoothing, but it made no difference (connected or not)

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"Des Bromilow"

** It's never a good idea to connect a large value cap across the output of a PWM motor drive circuit. Such circuits need to see a resistive or inductive load - in the latter case the current can then approximate smooth DC.

A large value cap spoils the whole operation of the circuit and likely cause excess peak current to flow in the switching mosfet.

The fact your 6800uF electro made no difference tells me that the PWM oscillator is simply not running.

..... Phil

On Sat, 05 Mar 2011 22:16:21 +0800, Des Bromilow put finger to keyboard and composed:

I'd start by measuring the voltage at the wiper of the pot, at both ends of travel, and at the centre. Is it linear or log?

The LM358 op-amp supply (pin #8) should measure 8.0V.

Pin #6 should be ...

8.0 x 47K / (47K + 39K) = 4.4V

BTW, here are the notes for the kit:

To view the redacted circuit diagram, drag a border around the image (Tools -> Basic -> Select Image), copy it to the clipboard (Ctrl-C or Edit -> Copy), and then paste it into your favourite image viewer.

- Franc Zabkar

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On Wed, 09 Mar 2011 16:18:25 +1100, Franc Zabkar put finger to keyboard and composed:

Actually, dragging a border is not necessary. Just single-click on the image to highlight it. You can see the circuit in the Clipboard Viewer (Window -> Clipboard Viewer), but it is mirrored and rotated.

- Franc Zabkar

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Is that using Adobe Acrobat? I'm using Foxit Reader and it doesn't work, obviously the complete image is still present in the pdf file. Tom

Hi, one thing to look for would be - are you using a linear potentiometer for your external control?

Greg

"gcd"

** The OP's symptoms are far worse than that would explain.

He's make some kind of stuff-up with the construction - like failing to solder a few leads to their pads or bridging pads.

.... Phil

On Wed, 09 Mar 2011 15:56:57 +1000, Tom put finger to keyboard and composed:

Yes, my instructions were for Acrobat Reader. BTW, you can also r-click the highlighted image and select Copy Image to Clipboard.

- Franc Zabkar

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"Franc Zabkar"

** None of them work at all using XP.

PDF files are not internally compatible with Windows.

.... Phil

Ive found free image from PDF extractor, it worked. Gave up Acrobat quite a while ago as its a huge to download, slow and sluggish.

Tom

Seems ok for me with XP Home SP3 + Adobe Reader 9. Copies image from adobe & pastes into MS Paint. Image aspect is screwy but easily stretched back.

I guess Oately will change their "protection" now Francs exposed the loophole.

On Wed, 09 Mar 2011 21:08:20 +1000, Tom put finger to keyboard and composed:

while ago as its a huge to download, slow and sluggish.

I use both Foxit and Acrobat Reader. Some PDFs are handled better by Acrobat, while some have "dictionary" errors and need to be handled by Foxit. Therefore I have modified Windows Explorer's r-click menu to give me a choice of "Open with Foxit" or "Open with Acrobat Reader".

I also speed up the launching of AR by disabling its unnecessary plugins:

- Franc Zabkar

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On Wed, 9 Mar 2011 20:29:21 +0800, "Dennis" put finger to keyboard and composed:

I first became aware of this security flaw when Mohammed Haneef's barrister uploaded the transcripts of his AFP interview to the world. I have a slow machine and on this particular day it was running even slower than usual. I could see the original transcript contents being rendered, then followed by the blacked out redactions. The stupid barrister had exposed Haneef's private phone numbers, email addresses, and home addresses, both in Australia and in India.

Worse still, an Italian schoolboy likewise exposed the redacted information in publicly released US military documents.

- Franc Zabkar

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I pulled a border around the image - hit CTRL C

opened corel draw, and pasted it. It was stretched, but could be pulled back into shape and saved

k

e &

I thought that Oatley were above these methods of doing things.

All this does is hurt their business and particularly support reputation. Their kits are normally so reasonably priced that the majority wouldn't go to the trouble of trying to "roll their own".

"kreed"

I pulled a border around the image - hit CTRL C

** Seems to all depend on the version of Acrobat being used.

PDF files are impervious to any such coaxing on my PC.

.... Phil

Get PDF image extractor from:

Seems to work ok, they also have some utilities like text extractor and more.

Tom

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