paulf
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| posted on 6/1/07 at 12:10 AM |
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Vb921 coil drivers,
I am need a couple of these for experimentation but cant find anywhere in the uk with them , has anyone got a couple spare?
Paul.
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wilkingj
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| posted on 6/1/07 at 11:45 AM |
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Anglia Components Wisbech CAMBS.
+44 (0)1945 47 47 47 Mon - Fri 8:00am to 6:00pm UK time (5:30pm Fridays).
Anglia Components
VB921
Well established Company in the Radio Communications Field.
1. The point of a journey is not to arrive.
2. Never take life seriously. Nobody gets out alive anyway.
Best Regards
Geoff
http://www.v8viento.co.uk
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paulf
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| posted on 6/1/07 at 06:03 PM |
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Thanks Geoff
I will try them on Monday , cannot tell from the web site if they have them in stock.
Im planning on developing an ignition box that doesnt need the ford Edis parts as they are getting in short supply here, my main decent scrapyard
closed down at Christmas so I am having problems finding parts for megajolts at sensible prices.
Paul.
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wilkingj
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| posted on 6/1/07 at 08:51 PM |
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Megasquirt does not need an EDIS unit. You can drive the coils directly from the MS unit with the coil drivers.
Geoff
1. The point of a journey is not to arrive.
2. Never take life seriously. Nobody gets out alive anyway.
Best Regards
Geoff
http://www.v8viento.co.uk
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paulf
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| posted on 6/1/07 at 10:10 PM |
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Im aware of that , its not for a megasquirt application.
i have built a few Megajolts and have now decided that it would be good to produce a unit that is ignition only for use with carbs and doesnt rely on
Ford ignition modules. My idea is to build a unit running the MSNS software but with no fuel injector outputs and stripped down to the basics
required. It would have the advantage over the edis of higher RPM capability and so could be used on carbed bike engines.
I have enough bits spare to build one but just need the coil drivers.
I hope to be able to produce something for a similiar price to a full megajolt installation with edis etc, but without the Edis requirement.
Paul
quote:
Originally posted by wilkingj
Megasquirt does not need an EDIS unit. You can drive the coils directly from the MS unit with the coil drivers.
Geoff
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djtom
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| posted on 7/1/07 at 12:05 PM |
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Did anyone see a price or a minimum order requirement - I couldn't see it on the site.
I'm after 2 x VB921 at present, so if it turns out that there is a minimum order, would anyone mind ordering a couple extra for me - I can sort
some funds out via Paypal.
Tom
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MikeRJ
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| posted on 7/1/07 at 04:59 PM |
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I'm after a couple as well if more orders needed...
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paulf
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| posted on 7/1/07 at 05:09 PM |
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I will call them tommorow and try and get a price and order requirements.
Paul.
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martyn_16v
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| posted on 7/1/07 at 06:37 PM |
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I'll have a couple too if you're needing to buy them in quantity 
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Syd Bridge
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| posted on 7/1/07 at 08:26 PM |
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Those things are standard To220 mosfets. From the spec sheet, they show as 440volt.
We had to use 600volt on the Mini stuff, because the lower voltage mosfets broke down and shut off the sparks all by themselves!
Something to think about, even though the MS stuff seems to be surviving merrily on the 440volt items.
Just a thought.
Cheers,
Syd.
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MikeRJ
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| posted on 8/1/07 at 12:36 PM |
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quote:
Originally posted by Syd Bridge
Those things are standard To220 mosfets. From the spec sheet, they show as 440volt.
They are not standard MOSFET transistors! The VB921 are specialy designed coil drivers that have built in high voltage clamps and current limiters.
It's pretty much a one component solution to driving an ignition coil.
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Syd Bridge
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| posted on 8/1/07 at 07:09 PM |
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Well, I know my son's mate is using fet's, and they're not those things. He did build the MS himself, and did make a few mods to
suit himself. Now doing a Ph.D in electronics at Southampton, so knows a little bit about the subject. I'll have to ask him when he's here
next.
Syd.
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paulf
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| posted on 8/1/07 at 08:41 PM |
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I spoke to them today .
Got a price of £1.82 each which is great but unfortunately there is a minimum order quantity of 500 so not a good option im afraid.
I will have a further search and if I find some available will post on here.
Paul.
quote:
Originally posted by djtom
Did anyone see a price or a minimum order requirement - I couldn't see it on the site.
I'm after 2 x VB921 at present, so if it turns out that there is a minimum order, would anyone mind ordering a couple extra for me - I can sort
some funds out via Paypal.
Tom
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MikeRJ
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| posted on 8/1/07 at 09:20 PM |
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quote:
Originally posted by Syd Bridge
Well, I know my son's mate is using fet's, and they're not those things. He did build the MS himself, and did make a few mods to
suit himself. Now doing a Ph.D in electronics at Southampton, so knows a little bit about the subject. I'll have to ask him when he's here
next.
Syd.
Syd,
You can use MOSFETs, but you need some external components to provide voltage clamping and current litming etc. You are just paying a bit more for
the convienience of a single component solution with the V921.
Because the Megasquirt wasn't designed to have two coil drivers the second one has to be hacked in with wires etc. so the less components the
better.
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djtom
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| posted on 11/1/07 at 04:58 PM |
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has anyone had any luck finding a UK supplier yet?
I've emailed Phil Ringwood at ExtraEfi.co.uk to see if he'll sell me a couple, but I'd still like to know where to get them from!
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paulf
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| posted on 11/1/07 at 11:43 PM |
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Found these Bu941 devices. Anyone have any thoughts about the suitability of them? .I dont know if i would need external dwell control is this
incorporated in the vb921s?
They are available from Rs components for about £3 each
http://docs-europe.electrocomponents.com/webdocs/010b/0900766b8010b6e1.pdf
Paul.
[Edited on 11/1/07 by paulf]
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MikeRJ
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| posted on 12/1/07 at 01:12 AM |
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Not a suitable direct replacement unfortunately, that's just a high voltage darlington transistor.
Most micro's would struggle to drive the base directly, another transistor driver stage would need to be used. It also includes no current
limiting, which would have to be handled externaly, and no high voltage clamp which would also have to be external.
Last downside is that a bipolar darlington has a high collector-emitter saturation voltage, i.e. when switched fully on it still drops a fair bit of
voltage. This means they tend to run hot and require bigger heatsinks than MOSFET or IGBT's.
Neither the VB921 nor this device have dwell control built in, that's down to the micro to control.
I've not found any other devices with the same functionality as the VB921, but there are quite a few modern devices designed to drive ignition
coils such as Fairchilds IGBT's which include on board voltage clamping (no
current limiting though).
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