voltage stabilizer connections

[JeffP]

Still sorting out the wiring on my early Elan Plus2 (50/1510).

I will try to add a photo to help clarify my question . My stabilizer has E, I and B terminal with the following connections. E has a black wire to ground. I has a green wire to ignition switch.

A wire from I is connected I assume through a diode (47000pF +/- 10% ) to a spade terminal on B. That spade terminal appears to be connected via a capacitor to ground.

Red/Green wires from B connect to the Tach and also ping on continuity testing to the fuel gauge and temperature gauge.

From what I have read (I'm a auto electric newbie) the connections although they may not be standard and are not clearly shown on the wiring diagram appear to be correct.

Is this right? Please see attached photo.

Many thanks for any insights.

[john.p.clegg]

E.... Earth
I..... Instruments
B.... Battery

J John

Edit

12 - 14V in , 10V out , case earthed and mounted vertically .

[Andy8421]

Smiths Instruments gauges of the period needed a stable 10V supply to work. Battery voltage is all over the place, so Smiths incorporated a 'voltage stabiliser' in the supply to the instruments.

'Stabiliser' is a strong word for what is a bimetallic strip, a set of contacts and a heater. The heater heats the strip, the strip bends and opens the contacts, the strip cools down, closes the contacts and it all starts over again. The output of the heater is proportional to battery voltage, so the 'on / off' ratio of the contacts changes as battery voltage goes up and down to give a stable average voltage. The output of the contacts isn't actually 10V, its a series of pulses that have the same heating effect as a 10V supply would have. For those who care, it is similar to the way a modern switch mode power supply works.

The contacts arc and spark as they open and close, and can cause interference on an AM radio. Those two capacitors you have (the component you list as a diode is also a capacitor) have been fitted by a PO and are there to supress the radio interference.

Were it me, I would show the 'stabilser' the door and buy a modern electronic equivalent. The usual suspects sell them - I am not sure that it is even possible these days to buy a stabilser that is bimetallic, I think they are all electronic inside. The modern unit won't need the capacitors, so bin those as well. If you aren't using AM radio and decide to keep the original stabiliser, then you can still bin the capacitors.

The connections are:

B - connects to the Battery supply (switched through the ignition)
I - connects to the Instruments
E - connects to Earth (most units don't have this terminal, but rely on the case of the stabiliser being bolted to a an earthed bolt)

Of mild interest is that the bimetallic units need to be mounted the right way up, and have TOP marked on them. Modern electronic versions don't care, but still have TOP marked on them. It is also interesting (to me at least) that the electronic versions are based on the LM7810, which is the integrated circuit that has been in continuous production the longest. Designed in 1967, it is period correct for the Elan.

Edit: Didn't see John's post until I had posted this. His post is quite correct, and much shorter....

[john.p.clegg]

Not a problem Andy , I think Jeff has all he needs now.

John

[geni]

merci de partager ces infos ,
J'ais besoin de connaitre le(s) adresse (s ) exact pour me procurer se stabilisateur électronique puisque nos revendeurs Lotus n'en savent rien
Si vous vous pouvez renseigner en infos .Merci
geni

[john.p.clegg]

ici

https://www.ebay.co.uk/itm/282480406434 ... 7qEALw_wcB

John

[geni]

Thank you, I contacted them that way.
So, by giving their e-mail addresses, we avoid having to ask again!
Thanks to you
geni