TB charging

[jeffrey townsend]

Hi,

My TB charging has been a problem for several years although it runs fine even on longish trips of 500 miles. The problem is as follows:

If I select low, high or sidelights on the plc2 switch then the ammeter shows a small (around 2 amps, 4 amps on sidelights) discharge at all engine speeds. The ignition light shows red but slightly dimmer than when engine is not running. If I switch the plc to headlight position the ammeter shows a good charge as should be expected. 

I have visually checked all connections to the plc2 switch and cjr3 fuse/control box  and they seem OK. All fuses are OK. I have checked the 2 resistance wires in the back of the control box and they look OK. I have the 3rd brush dynamo fitted.

I am not an automotive electrical engineer and am struggling to work out what is wrong. Is there anyone who has had a similar experience on a TA/B or who can suggest what may be wrong? Could it be the plc2  switch itself maybe not making an internal connection? Does anyone rebuild and test these?

It seems odd that all is fine when headlights are selected but not when the selector switch is in the other 3 positions.

Regards to all,

Jeff   Cambridgeshire UK   TB0489

[eworpe]

Hi Jeff, Your problem would seem to be a lack of connectivity between the dynamo output D and the field coil F, except when Headlamps are selected. The third brush seems to be set up to give a "good charge" on Headlamps, so increasing the charge rate set up by adjusting the third brush may exceed the dynamo rating when using Headlamps. There should be two permanently connected resistors in series between D (dynamo output ) and F (field connection) in the control box. This sets up the "low" charge rate. When High or Sidelights are selected, the dynamo output is connected to F1 on the switch and this in turn is connected to the mid point of the two resistances (F1 in the control box) thus shorting out one of the resistances and increasing the current supplied to the field coil. When Headlamps are selected, the dynamo output is connected to F2 on the switch and this goes directly to F2 on the control box and then on to the field terminal of the dynamo. The current output of the dynamo in this situation is set up solely by the third brush as there are no resistances in series with the field coil. Your problem seems to be that there's no connection between D and F2, either through the switch, the fuse, the resistances or the wiring, other than when the switch is in the Headlamp position. Given that the two resistances should be permanently connected between D and F2 in the control box, this seems worth investigating. Hope this helps, Eric. ________________________________________ From: jeffrey townsend jeff.townsend@hotmail.co.uk If I select low, high or sidelights on the plc2 switch then the ammeter shows a small (around 2 amps, 4 amps on sidelights) discharge at all engine speeds. The ignition light shows red but slightly dimmer than when engine is not running. If I switch the plc to headlight position the ammeter shows a good charge as should be expected. I have visually checked all connections to the plc2 switch and cjr3 fuse/control box and they seem OK. All fuses are OK. I have checked the 2 resistance wires in the back of the control box and they look OK. I have the 3rd brush dynamo fitted. I am not an automotive electrical engineer and am struggling to work out what is wrong. Is there anyone who has had a similar experience on a TA/B or who can suggest what may be wrong? Could it be the plc2 switch itself maybe not making an internal connection? Does anyone rebuild and test these? It seems odd that all is fine when headlights are selected but not when the selector switch is in the other 3 positions.

[Andrea VILLA]

Attachments :

[*][url=file:///C:\Users\Steve\AppData\Local\PG Offline 4\Attachments\\IMG_0527.JPG]IMG_0527.JPG[/url]

Switch to LED -Headlamps  and Tail lights- dramatically lowering the Ampere absorbed Led 1Amp x LED H lamp versus 10 Amp x Trad. H Lamp-your dynamo are right but technology are oldest 100 years -no more power can be asked from it- night trips are problematic on al MMMcars and TC TD  without switch to LED lights (easy lamps substitution)  or switch to Alternator (more intrusive modifications) Turn lights are  sporadically used, my opinion is that the modification aren't  favourable - consider also that conversion can be problematic on flasher unit-due the different  Amp absorbent   http://www.dynamoregulatorconversions.com/led-headlamp-bulbs-shop.php Any commercial Interest on this Company- [b]Only [/b]my TC Electrical abs. Problems solved 

[Michael Leckstein]

Eric, since your reply to this topic indicates that you have some real knowledge of the mysteries of 3 brush generators, I was wondering if you can speculate on my cars strange behavior. I refer to a J2 and a PA, but both have three brush generators so the topic might be relevant to TA's. TBs. Both have the third brush connected and acting as the regulators. Both cars are connected to battery maintainers so the batteries are fully charged after storage periods. Both cars have diodes instead of cut outs as I don't trust cutouts on these very old cars. The diodes do not have any regulator circuits (which are available ) but are simple one way highways for the current. Now the mystery. When the J2 is started the red light stays on for about a minute or two (regardless of engine speed) then goes out and a good charge registers, up to 8 amps (the safe limit of the generator) Why the delay? The Pa is much worse, (I took out the red light bulb as it would stay on for as long as 10 minutes before a charge would suddenly come on, and everything then would be normal with 8 amps of charge. This has been discussed on the MMM Register Forum with no real explanation. Lack of" residual magnetism" was suggested by some but never endorsed by those who understand the dynamics of the generator. I certainly do not understand. It is a mystery that seems to do no harm, as eventually the charge begins. I note this all happens no matter what setting on the ignition switch or light selection is chosen. For headlights, you get a strong discharge until the system wakes up! Mike Leckstein -----Original Message----- From: mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com] On Behalf Of E.Worpe@surrey.ac.uk [mg-tabc] Sent: Tuesday, January 30, 2018 5:31 AM To: jeff.townsend@hotmail.co.uk Cc: mg-tabc@yahoogroups.com Subject: [mg-tabc] RE: TB charging Hi Jeff, Your problem would seem to be a lack of connectivity between the dynamo output D and the field coil F, except when Headlamps are selected. The third brush seems to be set up to give a "good charge" on Headlamps, so increasing the charge rate set up by adjusting the third brush may exceed the dynamo rating when using Headlamps. There should be two permanently connected resistors in series between D (dynamo output ) and F (field connection) in the control box. This sets up the "low" charge rate. When High or Sidelights are selected, the dynamo output is connected to F1 on the switch and this in turn is connected to the mid point of the two resistances (F1 in the control box) thus shorting out one of the resistances and increasing the current supplied to the field coil. When Headlamps are selected, the dynamo output is connected to F2 on the switch and this goes directly to F2 on the control box and then on to the field terminal of the dynamo. The current output of the dynamo in this situation is set up solely by the third brush as there are no resistances in series with the field coil. Your problem seems to be that there's no connection between D and F2, either through the switch, the fuse, the resistances or the wiring, other than when the switch is in the Headlamp position. Given that the two resistances should be permanently connected between D and F2 in the control box, this seems worth investigating. Hope this helps, Eric. ________________________________________ From: jeffrey townsend jeff.townsend@hotmail.co.uk If I select low, high or sidelights on the plc2 switch then the ammeter shows a small (around 2 amps, 4 amps on sidelights) discharge at all engine speeds. The ignition light shows red but slightly dimmer than when engine is not running. If I switch the plc to headlight position the ammeter shows a good charge as should be expected. I have visually checked all connections to the plc2 switch and cjr3 fuse/control box and they seem OK. All fuses are OK. I have checked the 2 resistance wires in the back of the control box and they look OK. I have the 3rd brush dynamo fitted. I am not an automotive electrical engineer and am struggling to work out what is wrong. Is there anyone who has had a similar experience on a TA/B or who can suggest what may be wrong? Could it be the plc2 switch itself maybe not making an internal connection? Does anyone rebuild and test these? It seems odd that all is fine when headlights are selected but not when the selector switch is in the other 3 positions. ------------------------------------ Posted by: e.worpe@surrey.ac.uk> ------------------------------------ ------------------------------------ Yahoo Groups Links

[Michael Leckstein]

Sorry if this went out twice -----Original Message----- From: Michael Leckstein [mailto:MGLeckstein@monmouth.com] Sent: Wednesday, January 31, 2018 7:24 AM To: 'E.Worpe@surrey.ac.uk'; 'jeff.townsend@hotmail.co.uk' Cc: 'mg-tabc@yahoogroups.com' Subject: RE: [mg-tabc] RE: TB charging Eric, since your reply to this topic indicates that you have some real knowledge of the mysteries of 3 brush generators, I was wondering if you can speculate on my cars strange behavior. I refer to a J2 and a PA, but both have three brush generators so the topic might be relevant to TA's. TBs. Both have the third brush connected and acting as the regulators. Both cars are connected to battery maintainers so the batteries are fully charged after storage periods. Both cars have diodes instead of cut outs as I don't trust cutouts on these very old cars. The diodes do not have any regulator circuits (which are available ) but are simple one way highways for the current. Now the mystery. When the J2 is started the red light stays on for about a minute or two (regardless of engine speed) then goes out and a good charge registers, up to 8 amps (the safe limit of the generator) Why the delay? The Pa is much worse, (I took out the red light bulb as it would stay on for as long as 10 minutes before a charge would suddenly come on, and everything then would be normal with 8 amps of charge. This has been discussed on the MMM Register Forum with no real explanation. Lack of" residual magnetism" was suggested by some but never endorsed by those who understand the dynamics of the generator. I certainly do not understand. It is a mystery that seems to do no harm, as eventually the charge begins. I note this all happens no matter what setting on the ignition switch or light selection is chosen. For headlights, you get a strong discharge until the system wakes up! Mike Leckstein -----Original Message----- From: mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com] On Behalf Of E.Worpe@surrey.ac.uk [mg-tabc] Sent: Tuesday, January 30, 2018 5:31 AM To: jeff.townsend@hotmail.co.uk Cc: mg-tabc@yahoogroups.com Subject: [mg-tabc] RE: TB charging Hi Jeff, Your problem would seem to be a lack of connectivity between the dynamo output D and the field coil F, except when Headlamps are selected. The third brush seems to be set up to give a "good charge" on Headlamps, so increasing the charge rate set up by adjusting the third brush may exceed the dynamo rating when using Headlamps. There should be two permanently connected resistors in series between D (dynamo output ) and F (field connection) in the control box. This sets up the "low" charge rate. When High or Sidelights are selected, the dynamo output is connected to F1 on the switch and this in turn is connected to the mid point of the two resistances (F1 in the control box) thus shorting out one of the resistances and increasing the current supplied to the field coil. When Headlamps are selected, the dynamo output is connected to F2 on the switch and this goes directly to F2 on the control box and then on to the field terminal of the dynamo. The current output of the dynamo in this situation is set up solely by the third brush as there are no resistances in series with the field coil. Your problem seems to be that there's no connection between D and F2, either through the switch, the fuse, the resistances or the wiring, other than when the switch is in the Headlamp position. Given that the two resistances should be permanently connected between D and F2 in the control box, this seems worth investigating. Hope this helps, Eric. ________________________________________ From: jeffrey townsend jeff.townsend@hotmail.co.uk If I select low, high or sidelights on the plc2 switch then the ammeter shows a small (around 2 amps, 4 amps on sidelights) discharge at all engine speeds. The ignition light shows red but slightly dimmer than when engine is not running. If I switch the plc to headlight position the ammeter shows a good charge as should be expected. I have visually checked all connections to the plc2 switch and cjr3 fuse/control box and they seem OK. All fuses are OK. I have checked the 2 resistance wires in the back of the control box and they look OK. I have the 3rd brush dynamo fitted. I am not an automotive electrical engineer and am struggling to work out what is wrong. Is there anyone who has had a similar experience on a TA/B or who can suggest what may be wrong? Could it be the plc2 switch itself maybe not making an internal connection? Does anyone rebuild and test these? It seems odd that all is fine when headlights are selected but not when the selector switch is in the other 3 positions. ------------------------------------ Posted by: e.worpe@surrey.ac.uk> ------------------------------------ ------------------------------------ Yahoo Groups Links

[Madhu Paroor]

Hi Mike let me put it in a rough simple way. If you force a child to eat who is not hungry, he/She will never eat !!! Now your battery is fully charged by external charger. So the why should the dynamo charge your battery after starting the engine ? If the battery voltage level goes down after few minutes. So then it will start charging !!! Sorry this is a simple way of thinking with out high technical knowledge. madhu 2018-01-31 13:24 GMT+01:00 'Michael Leckstein' mgleckstein@monmouth.com [mg-tabc] mg-tabc-noreply@yahoogroups.com>:

[u][/u] Eric, since your reply to this topic indicates that you have some real knowledge of the mysteries of 3 brush generators, I was wondering if you can speculate on my cars strange behavior. I refer to a J2 and a PA, but both have three brush generators so the topic might be relevant to TA's. TBs. Both have the third brush connected and acting as the regulators. Both cars are connected to battery maintainers so the batteries are fully charged after storage periods. Both cars have diodes instead of cut outs as I don't trust cutouts on these very old cars. The diodes do not have any regulator circuits (which are available ) but are simple one way highways for the current. Now the mystery. When the J2 is started the red light stays on for about a minute or two (regardless of engine speed) then goes out and a good charge registers, up to 8 amps (the safe limit of the generator) Why the delay? The Pa is much worse, (I took out the red light bulb as it would stay on for as long as 10 minutes before a charge would suddenly come on, and everything then would be normal with 8 amps of charge. This has been discussed on the MMM Register Forum with no real explanation. Lack of" residual magnetism" was suggested by some but never endorsed by those who understand the dynamics of the generator. I certainly do not understand. It is a mystery that seems to do no harm, as eventually the charge begins. I note this all happens no matter what setting on the ignition switch or light selection is chosen. For headlights, you get a strong discharge until the system wakes up! Mike Leckstein -----Original Message----- From: mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com] On Behalf Of E.Worpe@surrey.ac.uk [mg-tabc] Sent: Tuesday, January 30, 2018 5:31 AM To: jeff.townsend@hotmail.co.uk Cc: mg-tabc@yahoogroups.com Subject: [mg-tabc] RE: TB charging Hi Jeff, Your problem would seem to be a lack of connectivity between the dynamo output D and the field coil F, except when Headlamps are selected. The third brush seems to be set up to give a "good charge" on Headlamps, so increasing the charge rate set up by adjusting the third brush may exceed the dynamo rating when using Headlamps. There should be two permanently connected resistors in series between D (dynamo output ) and F (field connection) in the control box. This sets up the "low" charge rate. When High or Sidelights are selected, the dynamo output is connected to F1 on the switch and this in turn is connected to the mid point of the two resistances (F1 in the control box) thus shorting out one of the resistances and increasing the current supplied to the field coil. When Headlamps are selected, the dynamo output is connected to F2 on the switch and this goes directly to F2 on the control box and then on to the field terminal of the dynamo. The current output of the dynamo in this situation is set up solely by the third brush as there are no resistances in series with the field coil. Your problem seems to be that there's no connection between D and F2, either through the switch, the fuse, the resistances or the wiring, other than when the switch is in the Headlamp position. Given that the two resistances should be permanently connected between D and F2 in the control box, this seems worth investigating. Hope this helps, Eric. ______________________________ __________ From: jeffrey townsend jeff.townsend@hotmail.co.uk If I select low, high or sidelights on the plc2 switch then the ammeter shows a small (around 2 amps, 4 amps on sidelights) discharge at all engine speeds. The ignition light shows red but slightly dimmer than when engine is not running. If I switch the plc to headlight position the ammeter shows a good charge as should be expected. I have visually checked all connections to the plc2 switch and cjr3 fuse/control box and they seem OK. All fuses are OK. I have checked the 2 resistance wires in the back of the control box and they look OK. I have the 3rd brush dynamo fitted. I am not an automotive electrical engineer and am struggling to work out what is wrong. Is there anyone who has had a similar experience on a TA/B or who can suggest what may be wrong? Could it be the plc2 switch itself maybe not making an internal connection? Does anyone rebuild and test these? It seems odd that all is fine when headlights are selected but not when the selector switch is in the other 3 positions. ------------------------------ ------ Posted by: e.worpe@surrey.ac.uk> ------------------------------ ------ ------------------------------ ------ Yahoo Groups Links

[Ron Benson]

Hi Jeff,

I had various problems with my TB, but mainly overcharging, tried all sorts including external resistances. Ended up throwing the towel in and getting it converted to solid state, never looked back, turned out that the field windings were shot on the dynamo as well. It was all done by Classic Dynamo and Regulator Conversions, I think they are in Norfolk, can highly recommend them.

 

Regards,

Ron Benson  TB.

[Tim Bloomfield]

I confess converting mine to solid state.  The late Bob Jeffers did the conversion.  I have the interior points and resistors should following owner wishes to go back.  Tim BloomfieldTB0613Rainy Louisiana Sent from Yahoo Mail on Android

[James Btass]

Attachments :

[*][url=file:///C:\Users\Steve\AppData\Local\PG Offline 4\Attachments\\Modifying a Three Brush Dynamo System to Solid State Regulation.pdf]Modifying a Three Brush Dynamo System to Solid State Regulation.pdf[/url]

Hi

 

I agree with Ron. The three brush system can only give a fixed charge based on the field current that is set by the position of the third brush relative to the earthed pickoff brush in the dynamo and the resistors that are switched into the field circuit. It can work reasonably but usually either over charges or under charges  the battery. I have converted my side lights to LED for visibility driving and at the same time converted the regulator and dynamo to solid state. This is an easy DIY job and what a difference it makes! I attach a short paper I wrote for the OCC explaining the modifications needed.

 

Regards

 

James Thomas

 

[b]From:[/b] mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com] [b]On Behalf Of [/b]'Ron Benson' ronb9131@virginmedia.com [mg-tabc] [b]Sent:[/b] 01 February 2018 16:11 [b]To:[/b] jeff.townsend@hotmail.co.uk [b]Cc:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] [mg-tabc] Re: TB charging

 

 

Hi Jeff,

I had various problems with my TB, but mainly overcharging, tried all sorts including external resistances. Ended up throwing the towel in and getting it converted to solid state, never looked back, turned out that the field windings were shot on the dynamo as well. It was all done by Classic Dynamo and Regulator Conversions, I think they are in Norfolk, can highly recommend them.

 

Regards,

Ron Benson  TB.

[Ron Benson]

Attachments :Hi James,

Good article, sadly don’t remember it in the OCC Magazine! I had the cut-out unit modified by CDRC when I sent them the dynamo. Well worth it.

 

Ron Benson

 

[b]From:[/b] James Btass [mailto:james.thomas@btass.com] [b]Sent:[/b] 02 February 2018 10:06 [b]To:[/b] 'Ron Benson'; jeff.townsend@hotmail.co.uk [b]Cc:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] RE: [mg-tabc] Re: TB charging

 

Hi

 

I agree with Ron. The three brush system can only give a fixed charge based on the field current that is set by the position of the third brush relative to the earthed pickoff brush in the dynamo and the resistors that are switched into the field circuit. It can work reasonably but usually either over charges or under charges  the battery. I have converted my side lights to LED for visibility driving and at the same time converted the regulator and dynamo to solid state. This is an easy DIY job and what a difference it makes! I attach a short paper I wrote for the OCC explaining the modifications needed.

 

Regards

 

James Thomas

 

[b]From:[/b] mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com] [b]On Behalf Of [/b]'Ron Benson' ronb9131@virginmedia.com [mg-tabc] [b]Sent:[/b] 01 February 2018 16:11 [b]To:[/b] jeff.townsend@hotmail.co.uk [b]Cc:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] [mg-tabc] Re: TB charging

 

 

Hi Jeff,

I had various problems with my TB, but mainly overcharging, tried all sorts including external resistances. Ended up throwing the towel in and getting it converted to solid state, never looked back, turned out that the field windings were shot on the dynamo as well. It was all done by Classic Dynamo and Regulator Conversions, I think they are in Norfolk, can highly recommend them.

 

Regards,

Ron Benson  TB.