Voltage Stabiliser

Date: Mon, 24 Aug 1998 18:25:04 +0100 (WET DST)
From: Dave Edge
Subject: Voltage Stabiliser

Hi All,

Can anyone help me with my voltage stabiliser, I have a number of a company that can supply me with a voltage stabiliser unit but they don't know what one. Could anyone with a Sunbeam Stiletto of the 68-69 vintage have a quick peak under the dash and tell me what the Smiths serial number is on the tin case, apparently it is not the one on the sticker but the actual number stamped on the casing, but in case it isn't could anyone make a check on both numbers.

My other option is to dismantle the unit I have and shorten the windings, as far as I know this will result in a lower output, I think!
- less winding means more heat therefore it will cut out sooner.

A silly question that I should have asked earlier but - does anyone have a spare (OK not free) imp crankshaft that could be machined for the 930 engine or indeed one that has already been machined because I am reluctant to dismantle my engine and remain impless for a whole week, what would I do for fun?


PS what were your ideas for basic circuits for remote throttle control, if large piccys are involved please send them to my account -

Date: Mon, 24 Aug 1998 23:00:47 +0100 (WET DST)
From: Nickcleak@aol.com
Subject: Re: Voltage Stabiliser

I gave up with the thermal type lucas regulators a long time ago , just get a solid state 10V regulator from an electronic component supplier , only cost a couple of pounds , have three terminals , input from car electrical systen , earth , and constant 10v Output to the gauges , i mounted mine inside the original regulator casing.

Nick ..

Date: Mon, 24 Aug 1998 20:22:24 -0400 (EDT)
From: Gary Henderson
Subject: Re: Voltage Stabiliser

Hi Dave

Is it the winding or just the contacts gone to grot? Sometimes you can ressurrect them just by twiddling the adjustment screw (count the turns!) and then resetting a little one side or other of original. J-U-S-T possible in situ. Otherwise take the can off & clean the contacts, then readjust using about 1000uF capacitor across your analogue multimeter (DMM no good - you'll go crazy because it won't be seeing a steady voltage.)

Now this IS a job that a modified CD-supply should be able to cope with... or else use a SMPS IC - I think you could dream up an inductorless version because the thermal instruments are pure-resistive and provide their own 'energy storage' as heat.

Good luck


Date: Tue, 25 Aug 1998 06:02:06 +0100 (WET DST)
From: rienk steenhuis
Subject: Re: Voltage Stabiliser

>I gave up with the thermal type lucas regulators a long time ago , just get a
>solid state 10V regulator from an electronic component supplier , only cost a
>couple of pounds , have three terminals , input from car electrical systen ,

these voltage regulators need 3V difference between input and output voltage. some will work with lower differnce but this is not guaranteed.
depending on the exact type and make you get chances are the regulator gets very hot because it starts to oscillate. this is why you should use a number of capacitors between input and ground and output and ground. on the output 10uF and 100nf parallel and on the input something like 100uf and 100nF parallel.

regarding the electronic throtle. i would be extremely cautious about making my own system or using a system from a shop like maplins. it is very hard to design a system that is guaranteed to be failsafe if you don't know the exact source and specification of the parts you're using. a 7810 voltage regulator as ordered by a company making medical equipment and a 7810 for a company making cheap hifi may carry the same name but they will be very different. and we as ordinary public have no way of finding out what exactly it is where buying. what we can get is basically surplus stock from unknown sources.


Date: Tue, 25 Aug 1998 02:43:30 -0400 (EDT)
From: Gary Henderson
Subject: Re: Voltage Stabiliser

This does sound like a minor project that needs to happen...

A couple of 555s and a PNP power transistor plus some R & C needed as a minimum - I'll think about it. Besides the 3 V drop, a linear 3-terminal regulator might have to dissipate about 2.5 W in this job - not dead easy inside a car in summer (even a nice cool Imp). The challenge is to make it reliable, and make it fit the old can! Then the challenge to others would be to re-engineer it for negative-earth...mine's a Mk 1 and old enough to resent change.



Date: Tue, 25 Aug 1998 13:05:06 +0100 (WET DST)
From: Dave Edge
Subject: Re: Voltage Stabiliser


I have already made a unit with two zener diodes and a couple of resistors but the resistors (necessary to protect the diodes) provided too high a resistance for the guages to move at all. The unit even had a pot which enabled me to vary the voltage from 9 to 11 volts, the circuit works with a DVM but does not even make the guage twitch and was stable to within a hundreth of a volt, needless to say I wasn't too happy after a few hours making the thing!

On my way home today I will be calling in at maplins, I have just realised that I have the perfect oppourtunity to fiddle with my carbs since they are going to be off the car whilst the engine is out for conversion.

I would disagree that Maplins components are inferior, I would suggest that it is just the case that we HOPE the circuitry that the health industry is more accurate, the fact is that stuff like this either works or it doesn't.

I have found a simple method of altering the voltage stabiliser to calibrate the guage, simply bend the prong where the live feed goes to the resistor mat, less contact = less volts and VV.

And for those sissys out there concerned with the safety aspects of a remote throttle, well I still have the ignition key to hand and as said earlier I will just leave the cable in for emergencys (Remove the clevis pin and split pin at the throttle end.

I think the major concern for reliability is going to be the heat from the exhaust whcih will be overcome with a housing covered in bacofoil!


Date: Tue, 25 Aug 1998 23:15:13 +0100 (WET DST)
From: Nickcleak@aol.com
Subject: Re: Voltage Stabiliser

Hi Rienk ,

> these voltage regulators need 3V difference between input and output voltage.

It was a 9v regulator with a resistor in series with the earth pin to get 10v.
my system voltage is 14.8 v .. it has been working a treat in the Clan for 100000km ..
The gauges are so much more stable ...

nick ...

Date: Wed, 26 Aug 1998 03:43:38 +0100 (WET DST)
From: tcjspencer@zetnet.co.uk (Trevor Spencer)
Subject: Re: Voltage Stabiliser

Mine is LUCAS and the label on the box for Current Voltage Regulator (it says on the plastic case) that I got I got for my '67 Sport, she's on her third, is:

NCB130 CONTROL BOX 1293 354

Hope this helps


Date: Wed, 26 Aug 1998 16:27:46 +0100 (WET DST)
From: Gary and Carol Henderson
Subject: RE: Voltage Stabiliser

Hi Dave

As a kid, when those things first appeared, I opened one in my Dad's workshop, expecting/hoping to find a nice big Zener diode - talk about disappointment!

A 7810 regulator will do it, but needs to be able to dissipate up to 2.5 W-odd when the temperature might be up to 65 degC (that's the normal design temp for car-radios etc.) OK they have a thermal protect of sorts so should usually survive the odd roasting...(I think the gauges need up to about 330 mA each for fsd) And some examples might not deliver a whole 10 V until the gene is charging, because the drop is up to 3 V. (Usually more like 2.4 V).

Taking a leaf out of Joe Lucas' book, a switching regulator has to be the way to go, but not using a heater + bimetal. Certainly feasible with 2 555s plus a PNP & a few bits; maybe one of the 555s can get the heave-ho as well.



Date: Thu, 27 Aug 1998 11:22:43 +0100 (WET DST)
From: Gary Harding
Subject: RE: Voltage Stabiliser

A single 7810 type device has been in use for a few years in my Californian in place of the original voltage regulator. It fits in the original can, it has not failed and it regulates to very close tolerances. I soldered the 7810 legs to the existing rivets and pop riveted the 7810 to the to the can. No stability capacitors have been used.