TR6 Alternator cold?

[barkerwilliams]

Started TR6 up when really cold and ran for 5 minutes. Ignition light stayed on and voltage gauge showed no more that 10 -11 volts.

 

Went out today for a better look at the problems and all is well, car starts easily and immediately charges.

 

Are alternator diodes that sensitive to the cold, I have never had one that was? Or is it more likely that a brush was not making good contact with a slip ring due to stiff grease on the brushes?

 

A real fault I can fix is reassuring, one that goes away leaves me concerned for the next time it appears.

 

 

 

 

Alan

[RogerH]

Hi Alan,

most semiconductors (diodes, transistors etc) like the cold. They don;t like it too hot.

 

Thick grease, or moisture in the grease, becoming stiff.

 

Roger

[Mike C]

Check the charging voltage with a multimeter and the engine speed above high idle. Should be above 13.5 volts.

Edited December 29, 2017 by Mike C

[Steves_TR6]

Check the ignition feed wire, i had similar symptoms with a loose connector.

 

( the acr alternator is ‘excited’ by an ignition feed on the thin brown wire, without it you get no charge and ignition light stays on)

 

Steve

[BlueTR3A-5EKT]

Disconnect battery first!

Unplug and re plug all connectors - That may be the source of the problem - a poor connection joint.

 

Next - If it is a Lucas alternator, simply unscrew the back cover and check the brushes, for protrusion and ease of movement in their brush holder. Renew if required.

Clean out any dust or dirt and wipe slip rings with meths coated cloth. This can be done without removing the alternator.

 

Peter W

 

PS What new brushes look like http://www.autoelectricalspares.co.uk/15-16-17-18-acr-alternator-brush-set-replacing-lucas-ulb108-54218706-1413-p.asp

Here is video from University Motors the MG fanatics on Lucas alternators. Brush box at about 4 minutes.

[Graham J]

As simple as the Fan belt not gripping in the cold?