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VeeTee

Member Since: 06 Mar 2011
Location: Somewhere
Posts: 1512

I wonder if you really need one. They are used to suppress electronic interence what would hear on the car radio as a whining noise. Modern car radios have a built in suppression unit. I would test if you really need one, if you do have an interference on your radio you could fit one, in general a value of 1-3 microF is used. A car radio shop can advise further. Cheers, Vincent
1959 Polynorm 1/4 Ton Trailer, Olive Drab Green (sold)
1970 M416 Military Trailer (Camping Trailer Conversion), Epsom Green (sold)
1975 Series III 88 V6, Light Green (sadly sold)
1996 Defender 110 CSW 300 Tdi, Epsom Green (sold)
2000 Freelander 1 TD4 3-drs, Silver (sold)
2006 Freelander 1 TD4 5-drs Facelift Automatic, Tonga Green (sold)

MySite

26th Dec 2015 10:51pm

schweps

Member Since: 21 Oct 2014
Location: Zonguldak
Posts: 47

2005 Defender 110 300 Tdi HT Alpine White

Now it is clear for me.
VeeTee, thanks for your all kind explanations.
Cheers.

27th Dec 2015 9:03am

schweps

Member Since: 21 Oct 2014
Location: Zonguldak
Posts: 47

With the help of the VDO document that VeeTee referred, rev counter is tested and it is working fine.
Terminal W was the bolt that I've circled and asked in earlier messages.

Click image to enlarge

My crank pulley dia is 175mm, alternator pulley dia is 50mm.
According to the formula "i" is calculated as 175/50=3,5 and impulse, 6x3,5=21
From the table, switch 2 is selected and all cables connected temporarily.
Idling rev was around 750-800rpm and response seems ok to the gas pedal.
Cheers.

27th Dec 2015 5:56pm

VeeTee

Member Since: 06 Mar 2011
Location: Somewhere
Posts: 1512

Seems all OK to me. Cheers

Cheers, Vincent
1959 Polynorm 1/4 Ton Trailer, Olive Drab Green (sold)
1970 M416 Military Trailer (Camping Trailer Conversion), Epsom Green (sold)
1975 Series III 88 V6, Light Green (sadly sold)
1996 Defender 110 CSW 300 Tdi, Epsom Green (sold)
2000 Freelander 1 TD4 3-drs, Silver (sold)
2006 Freelander 1 TD4 5-drs Facelift Automatic, Tonga Green (sold)

MySite

27th Dec 2015 7:08pm

schweps

Member Since: 21 Oct 2014
Location: Zonguldak
Posts: 47

I'm a restless guy, I admit that.
At my calculation and while using the table I might have made wrong assumptions.
Like as; for the rpm column the numbers (4000, 6000 and 8000) I considered them as the dial limit of the rev counter.
But now I understand they are not. The rpm value refers to the max rpm of the alternator. Thanks god, they are both same for dial limit of the rev counter and max rpm of the alternator.

For the number "6" from the formula, I considered that as a constant value. But now I realized that it refers to number of pairs of poles. From the alternator data table above, "Field winding rotor poles" is given as 12. So when we call pairs, shall we divide it by 2 ? Or whilst it is three phase shall we divide it by 3 ?

If it shall be 12/2, then my assumptions are correct by chance.

Cheers.

28th Dec 2015 9:54am

VeeTee

Member Since: 06 Mar 2011
Location: Somewhere
Posts: 1512

Regarding the number of poles, you are correct, 12 poles is 6 pairs.

Why dou you think the 6000 refers to the max. rpm of the alternator? I think it refers to your first assumption, the scale of the rev.counter. Let me put it like this, if you have an alternator with same pulley dimensions and same number of poles, but other max. rpm, the frequency (pulses per second) at a given engine speed does not change. On the other hand, if you put in a tachometer with a different scale you have to adapt to the scale of the meter. Don't know if it sounds logic, but this is how I would think it works.

Edit: if you look at the document in my first link, it says:

Quote:

Ist die Impulszahl (Impulse am Ausgang Klemme W der Drehstromlichtmaschine pro Umdrehung des Motors) bekannt, den Kodierschalter nach der Kodiertabelle einstellen

so they are talking about the number of impulses per revolution of the engine, not per revolution of the alternator... Cheers, Vincent
1959 Polynorm 1/4 Ton Trailer, Olive Drab Green (sold)
1970 M416 Military Trailer (Camping Trailer Conversion), Epsom Green (sold)
1975 Series III 88 V6, Light Green (sadly sold)
1996 Defender 110 CSW 300 Tdi, Epsom Green (sold)
2000 Freelander 1 TD4 3-drs, Silver (sold)
2006 Freelander 1 TD4 5-drs Facelift Automatic, Tonga Green (sold)

MySite

28th Dec 2015 4:01pm

schweps

Member Since: 21 Oct 2014
Location: Zonguldak
Posts: 47

I've googled too much about this and some how I had the impression that it should be the alternator's max rpm.
And when I pass through the vdo document, I noticed 3000rpm and 7000rpm scaled rev counters to support this impression.
But after your message I checked the document again and saw tables including those rpm's aswell (page 3-11)

Since now I was focused on 52mm ones at page 5-11.
So you're right and every thing seems ok.
Cheers.

28th Dec 2015 4:54pm

VeeTee

Member Since: 06 Mar 2011
Location: Somewhere
Posts: 1512

Since it's both 6000 it does not matter for now, but I am always curious to know why it is or works the way it is...

Cheers, happy driving!

28th Dec 2015 5:25pm

schweps

Member Since: 21 Oct 2014
Location: Zonguldak
Posts: 47

As long as there are impulse tables for 3000 & 7000rpm like below,
no doubt VeeTee, you are absolutely correct.

Click image to enlarge

28th Dec 2015 7:46pm

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