Voltage Regulator

[arceye]

Right, so I'm on with a multitude of little jobs with the Riley RM in an effort to put enough of it back together before turning it around and starting on the back end.

So I have been cleaning electrical connectors and tidying wiring in the engine bay area and knowing that the car wasn't charging (ignition light always on) I cleaned up all the contacts on the Regulator and voila, light now goes out on tickover.

The problem is that on increasing revs the light comes back on and glows brighter as revs increase, If I manually trip the contact over the light goes off and stays off but then the contact doesn't let go when the revs drop back to tickover.

So, any fixes? or throw it and get another. I have not altered either of the two contact adjusters so it is set up as it was when it was put away in 67.

Thanks for advice / opinions

[suffolkpete]

Dynamos need a certain amount of residual magnetism in order to start charging. I wonder if this has disappeared over the years. Try flashing the D terminal on the dynamo with battery voltage. Can't remember whether the Riley is negative or positive earth.

[arceye]

Hi Pete, the dynamos putting power out, and if I manually trip the lower contact on the voltage regulator (this is the one at the D end of the regulator) when I go to fast idle I get plenty going to the battery (14 volts upwards) and the bulb goes out but the contacts dont seem to want to trip in on their own if that makes sense.

So at idle I'm getting a low charge, but on raising the revs the extra power appears to be going through the ignition bulb unless I press the contact down physically. Once pressed down it stays there.

[arceye]

A slight update,

If I alter the adjuster for what I now believe is the "cut out" so as to lessen the springs tension on the contact, then it works and flicks over when revs are increased. It also opens up again as it should when revs drop to idle speed.

BUT... when I turn off the ignition it closes again and tries to power the dynamo.

Any thoughts? It is probably easier just to replace the unit but I'd quite like to repair it and gain a better understanding of it.

[suffolkpete]

I'm assuming you've got the standard Lucas five terminal regulator. If you have,then the one at the D end is the cut-out and the other one is the regulator. The cut out should come in at about 12.7 volts and the regulator at 15.6 to 16.2 volts, open-circuit (with A and A1 removed and connected together). It sounds as if the cut out points aren't opening. Also, check that you've got a good earth connection at the E terminal. People think these boxes are a black art, but they're easy to set up with a set of feeler gauges and a voltmeter. I'll try and scan a copy of the manual, it's for an Austin A50 but should be similar.

[arceye]

Cheers Pete, it is a 5 screw terminal Lucas, and I would think an A50 set up is the same so a scan would be great.

AND...... surely anything with LUCAS on it is the devils own work?

I'm going to try and get another look later but the inconsiderate other half decided to be admitted to hospital last night for the second time this month with bloody gallstones.....so I'm back on domestic duties Now, where did she leave the apron.......

[suffolkpete]

I've scanned two pages of the manual, couldn't attach them so here is a SkyDrive link https://skydrive.live.com/redir.aspx?ci ... parid=root
Basically the control box consists of two voltage sensitive relays. The cut-out is normally open and the regulator closed when the engine is idling. As the revs increase, the cut-out points (Fig.15) close and connect the dynamo output (D) to the battery (A & A1). At the same time the contacts by-pass the ignition warning light, causing it to go out. Field current is supplied by the closed regulator contacts 7 (Fig. 13) and F. As revs continue to rise, the voltage increases and the regulator operates, opening contacts (7) and disconnecting the field current. The resulting drop in output voltage causes the regulator to release and re-connect the field current until the regulator operates again. This process repeats at high speed, maintaining the output at the regulated voltage. When the revs drop, the cut-out points open and the dynamo output is disconnected.
The settings are, cut-in voltage 12.7 - 13.3 volts, drop out voltage 8.5 - 11 volts, regulator open-circut voltage 15.6 - 16.2 volts

[tractorman]

There's a Lucas manual in pdf that may help:

http://www.atcc.org.nz/tcc/LucasFault.pdf

Although the (RB340?) regulator has spade terminals, the principle is the same!! I've seen other similar guides that may help - it's worth a search to find one that's written in simple and clear English!

[arceye]

Thanks Pete and Tractorman,

Both duly downloaded for further perusal and I will have a go at setting it up correctly the next chance I get.

[arceye]

O.k, gave up with the original unit and took a chance on a new old stock lucas "exchange" unit.

Now, I THINK that I got the wires back at the appropriate terminals (I have no way of knowing if they were correct to start with) but all I get is a steady ignition light with nothing showing on the ammeter. However, if I bridge accross terminals D and F of the regulator the cut out works and the car seems to charge as it should with a healthy amperage shown on the Ammeter and a good voltage to the battery.

Any thoughts before I play. The only thing I can think to check is that the D and F wires from the dynamo are going to the correct terminals, does it sound possible that they are currently the wrong way round?

I'll disconnect and check them tomorrow to make sure they are going to the respective terminals, any other ideas before I start?

Thanks chaps.