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Forum Index : Electronics : Possibly cheap parts in Oz - Q. to Gill

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domwild
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Joined: 16/12/2005
Location: Australia
Posts: 873

Posted: 05:32am 23 Mar 2007

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Silicon Chip, current issue, page 43 lists surplus electronic components from Rockby Electronics.

200V 2x30A super fast diodes $1.50 part SF3004PT
60V 70A 35W N-Ch MOSFET $1.00 part 2SK3061 NEC

This MOSFET is powerful; perhaps experts like Gill with their "black belt in electrickery" may be able to tell me
if it can be used in place of the SDB85N03L to use back-EMF braking or are we talking about apples and pears?

Thanks.

Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.

Winston Churchill

Gill

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Joined: 11/11/2006
Location: Australia
Posts: 669

Posted: 01:19pm 23 Mar 2007

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Gee Dom, you sure know how to put a bloke on the spot.

I'm guessing your going to retro fit just the breaking part of that controller circuit to your existing charging circuit.

So, looking to diodes, seems OK, though I would use more. Say 4, as parallelling 2 diodes does not give double the amp capacity as you might expect.

Now the mosfet seems OK too. Once again I would use more. Try 2, to be sure to be sure. Make sure to get the pin-out arrangement when you order so you can connect correctly.

I am surprised to see no heat sink on these mosfets on the assembled kit. I couldn't help myself... I would.

Best of luck with the mod.

was working fine... til the smoke got out.
Cheers Gill _Cairns, FNQ

domwild
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Joined: 16/12/2005
Location: Australia
Posts: 873

Posted: 04:39am 24 Mar 2007

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Gill,

Thanks for that. Am using three of the 35A metal-case rectifiers, so I do not intend to use those diodes for the rectification. The diode info is for members of the forum, who may find those prices to be reasonable.

Am tempted to add the back-emf braking despite the fact that my PVC props seem to stall rather than overspeed anyway, this seems to be a problem with the profile. Besides, using the Picaxe, this could be progammed easily based on RPM should it be necessary.

From memory,when I searched the web for the SDB85N03L I did not get a hit, which is strange. Oatley's web site seems to be out of order at the moment.

Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.

Winston Churchill

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