Dynamo/Generator Problem

[MikeMarjot@aol.com]

Dear all, I have an electrical 'problem' (challenge?) on my TB. I am a novice regarding things electrical. I am having problems with the small dynamo (generator) brush on my 3 brush dynamo. The spring clip is causing a short because the brush is so worn it is allowing the spring clip to ground on the metal surround. I have a temporary fix to keep me going but need some advice. The dynamo is a C45NV3 3 brush. Clausager says the ref should be C45NV2, 1. Is there any difference? 2. Where can I get a replacement set of 3 brushes? (preferably UK) The ignition switch on my TB is a TC switch NOT a TA/TB switch. The TA/TB switch would allow the choice of high/low charge. So presumably I am not getting the 'benefits' of the three brush dynamo. 3. Is that right? 4. Can I simply disconnect the 3rd (small) brush, which is causing the problem and make it a 2 brush dynamo? I also have another dynamo C45PVS which I am told is for a TC although Clausager says it should be a C45YV! 5. Will this 2 brush dynamo work with my TB and what do I need to do to install it successfully in place of the current dynamo? I would like to transfer the pulley/fan over from the 3 brush (C45NV3) to the 2 brush (C45PVS). 6. Will it fit? 7. How do I get it off the old dynamo? I have undone the nut and washer but it seems 'firmly fixed in place' and I don't want to damage the fan etc. Mike Marjot TB 0450

[Dean Jensen]

Mike to answer a couple of your questions (2) any one that repairs motors or generators should be able to supply the brush that you need, they can make the brush out of stock, the only thing important is to get a brush that is the right hardness. Do you have a voltage regulator/cut out box, that you are using with the generator to make it work? To remove the pulley/fan you may end up wasting it, if you have a bearing puller, if you can get it behind or even in the pulley groove you may be able to get it off, using a gear puller, when you get it tight, if it does not come off, easily, and you are afraid that you are going to break the pulley, strike the end with a hammer, this helps sometimes. Would have to do some checking on the rest of your questions, I no one else responses, will get back to you. Cheers Dean

----- Original Message ----- [b]From:[/b] MikeMarjot@aol.com [b]To:[/b] mg-tabc@yahoogroups.com [b]Sent:[/b] Monday, April 09, 2001 5:27 AM [b]Subject:[/b] [mg-tabc] Dynamo/Generator Problem Dear all, I have an electrical 'problem' (challenge?) on my TB. I am a novice regarding things electrical. I am having problems with the small dynamo (generator) brush on my 3 brush dynamo. The spring clip is causing a short because the brush is so worn it is allowing the spring clip to ground on the metal surround. I have a temporary fix to keep me going but need some advice. The dynamo is a C45NV3 3 brush. Clausager says the ref should be C45NV2, 1. Is there any difference? 2. Where can I get a replacement set of 3 brushes? (preferably UK) The ignition switch on my TB is a TC switch NOT a TA/TB switch. The TA/TB switch would allow the choice of high/low charge. So presumably I am not getting the 'benefits' of the three brush dynamo. 3. Is that right? 4. Can I simply disconnect the 3rd (small) brush, which is causing the problem and make it a 2 brush dynamo? I also have another dynamo C45PVS which I am told is for a TC although Clausager says it should be a C45YV! 5. Will this 2 brush dynamo work with my TB and what do I need to do to install it successfully in place of the current dynamo? I would like to transfer the pulley/fan over from the 3 brush (C45NV3) to the 2 brush (C45PVS). 6. Will it fit? 7. How do I get it off the old dynamo? I have undone the nut and washer but it seems 'firmly fixed in place' and I don't want to damage the fan etc. Mike Marjot TB 0450 Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.

[C. Knight]

MikeMarjot@aol.com wrote: Re: TB

> The dynamo is a C45NV3 3 brush. Clausager says the ref should be > C45NV2, > 1. Is there any difference?

I don't think so. MG listed 2 dynamos for TBs with the change over at engine XPAG XPAG883. There were no changes to the control box.

> The ignition switch on my TB is a TC switch NOT a TA/TB switch. The > TA/TB switch would allow the choice of high/low charge. So > presumably I am not getting the 'benefits' of the three brush dynamo. > 3. Is that right?

No. What you will get is the "full" charge of about 10 amps vat all times. The 3rd brush will still be doing its job controlling the dynamo. The batteries will gas off a bit and may need replenishing more regularly. I would suggest changing the switch only when you find one at a "fair" price.

> 4. Can I simply disconnect the 3rd (small) brush, which is causing the > problem and make it a 2 brush dynamo?

Not unless you rewire with a TC type regulator. A new brush will be a lot cheaper.

> I also have another dynamo C45PVS which I am told is for a TC although > Clausager says it should be a C45YV! > 5. Will this 2 brush dynamo work with my TB and what do I need to do > to install it successfully in place of the current dynamo?

You need to install a TC regulator if you want to use this dynamo.

> I would like to transfer the pulley/fan over from the 3 brush (C45NV3) > to the 2 brush (C45PVS). > 6. Will it fit?

The TB pulley should be the same as TC (MG862/75 - could someone with a TC parts list check that this is also a TC pulley please?). The TA is a different one (MG706/205). I can confirm that the TC pulley fits the TA/early TB dynamo.

> 7. How do I get it off the old dynamo?

Try a 3 jaw gear puller - not expensive and a useful tool. First soak the shaft with WD40 or similar. Tap the side of the pulley with a hammer as you tighten up the puller bolt. If nothing moves leave overnight with more WD40 and repeat tapping next day. If you do break the pulley replacements are available at reasonable prices. Best of luck Cliff

[Dave Norris]

2. Where can I get a replacement set of 3 brushes? (preferably UK) Try your local branch of Lucas Service - they provided mine. Failing that the Green Spark Plug Company should be able to help. Cheers, Dave Aberdeen TC9964

[MikeMarjot@aol.com]

Many thanks to all who replied on this issue. I have learned a little more and will act on the advice given. Cheers. Mike Marjot TB 0450

[Dwyer]

Mike The ignition/charging switch is not your main problem if you want to use a 2-brush dynamo on your TB. Cars with a 2-brush (CVC) charging system have a regulator which continuously turns the field windings (and hence the dynamo charge) on and off, so as to maintain an average charge rate suited to the dynamo speed and battery state. This unit also contains a cutout which disconnects the dynamo when its voltage falls too low, ie when idling or stopped. This stops the battery discharging through the dynamo and trying to drive it as a motor. On the other hand, 3-brush cars have only the cutout and no means of regulating the charge rate on a continuous basis. The charge rate has to be preset under stated conditions (perhaps 3000 rpm with headlights on, or something) using the third brush adjustment. So if you wish to fit a TC dynamo you must also fit the TC type regulator. You will need to make one or two wiring changes but it's quite possible. On the other hand, for the sort of driving that most of us do (on roads rather than night rallies) there's no big advantage in CVC systems. If you can get new brushes that will be a whole lot less trouble. Regards Dave Dwyer J2, TA, TC