26 replies to this topic

[Spider]

Sounds like the commutators have been coming to bits. They don't like 'high' RPMs (hence why they are fitted with a bigger pulley than alternators) but even so, with a more or less stock engine, you'd be hard pressed getting enough RPMs from it to do this.

 

Another cause for them coming apart is high current flow through the commutator for a continuous period.

 

I doubt this would be the issue, but just to mention it. The Bearing in the front end is electrically insulated from the frame and this insulation must be maintained. Usually though, if it does short across this, the Bearing fails rather then the issues you are seeing, but, if it doesn't fail, then it will cause the armature to get VERY hot and fail in short time.

[MikeJE]

Sorry for resurrecting this thread, but the alternator that looks like a dynamo (Dynamator? not sure what make) has failed on my 998 mini (it's a '62 traveller but with a replacement 998 engine and negative earth). I took it to a local auto electrician who tested it and confirmed its demise. He said the internal regulators come from China, are poorly made and difficult if not impossible to replace.

 

Has anyone any experience with these and can recommend or suggest something likely to last, please? It's only used for ordinary road travel so no high revving!

 

Many thanks once again.

 

Best wishes

 

Mike

[Spider]

Often a Alternator Regulator from a similar Output and Rotor Resistance can fitted. There are (or were, been a while since I needs to look !) Universal Regulators. Either of these will likely end up being external to the Alternator, but if you look around, you might find one that will fit internally.

 

< Edit: By chance, while looking for something else, I stumbled over a Spare Regulator I used to have in the Rally Car

 

   >

Edited by Moke Spider, 19 October 2019 - 02:04 AM.

[MikeJE]

Thanks Mokespider - My auto electrician has doubts about finding a regulator to fit the expired unit as they come from China, but notice the one in your pic is made by Bosch (or at least is stamped as such!). I may open the unit and see what's inside before I buy a replacement. If it is something I can find a replacement for, I will give it a go as replacements are expensive.

 

If I need to buy a replacement there seems to be three alternatives: Dynamator available from most places at about £150; Minispares and others sell a Dynalite at about £500 (!) and I have seen online a further alternative called a Dynator (see https://www.autoelec...roduct_list/197) for £300 but which seems to have the advantage of a 3 year warranty.

 

Has anyone any experience of using any of these, please?

 

Kind regards

 

Mike 

[alpder]

This is a thread resurrection, but I thought it worthwhile just to keep reports of Dynamator failure in the same place.

 

My Dynamator just failed. Bought new 2023, sat on the shelf a year, then it's done six months in the car, 2,500 miles. It just ceased generating - and it did so silently without even illuminating the "IGN" lamp. There's volts supplied to the energiser pin but the pin isn't drawing any current (which in turn means the IGN lamp doesn't illuminate to tell you there's a fault) and the Dynamator generates nothing at its output.

 

These things are - by far - the cheapest of the dynamo lookalikes out there. (Edit: Even so, £189.95 seems like plenty enough money to build a decent alternator - being roughly three times the typical price of a Lucas-type ACR.) I guess a TudorCarParts Dynamator is a Good Buy only if you like creating opportunities to meet AA personnel.

 

I'll tear it apart later and see if I can find what's failed. Maybe it can be repaired/uprated to make it reliable.

Edited by alpder, 02 September 2024 - 08:22 AM.

[Spider]

This is a thread resurrection, but I thought it worthwhile just to keep reports of Dynamator failure in the same place.

 

My Dynamator just failed. Bought new 2023, sat on the shelf a year, then it's done six months in the car, 2,500 miles. It just ceased generating - and it did so silently without even illuminating the "IGN" lamp. There's volts supplied to the energiser pin but the pin isn't drawing any current (which in turn means the IGN lamp doesn't illuminate to tell you there's a fault) and the Dynamator generates nothing at its output.

 

These things are - by far - the cheapest of the dynamo lookalikes out there. I guess they're a Good Buy if you like creating opportunities to meet AA personnel.

 

I'll tear it apart later and see if I can find what's failed. Maybe it can be repaired/uprated to make it reliable.

 

By the sounds of what's happened to yours it too sounds like the regulator has gone karput.

 

That Bosch Regulator I posted above, I forgot to mention in that post, it's an external Regulator. These are small enough that they could easily be fitted inside say a dummy Dynamo Regulator, that you might use with a Dynamator.

 

[alpder]

If only it was just the reg. But what's actually happened is the result of a pretty bizarre mechanical design that's almost guaranteed to rapidly fail. Here are some pictures, and I'll try to explain what I'm seeing.

 

Edit: These notes relate to a TudorCarParts brand "Dynamator" C39/C40 like this: https://tudorcarpart...ynamator-c39-40

 

Firstly, on the back of the Dynamator, there's a threaded collar and, inside the collar, is a slotted round shaft which rotates with the armature. I.e. it's some kind of PTO. But there's a plastic cover over it which I've never looked under before. Presumably, on the original C39/C40 there is something driven by this output? Otherwise, this little PTO shaft is absolutely pointless. And, if it wasn't present, my Dynamator would still be working.

 

Here's a picture of the shaft, which runs in a plain bearing in the backplate. It's already badly worn on the bearing faces. The small slotted end is the "output". The big slotted end fits onto the end of the armature, after the slip-rings, where there is a flat-sided end which fits into the big slot.

 IMG_20240831_201938.jpg   56.65K   0 downloads

 

This PTO's bearing sleeve is separate from the main armature bearings. The sleeve is very short, so the PTO shaft is not properly held in place true to the axis of the main armature. And there's nothing to centre the shaft onto the end of the armature shaft / slip-ring axle. You can see the PTO hasn't engaged centrally on the flatted end on the armature: the wear marks (which are huge) are waaay off-centre.

 IMG_20240831_202019.jpg   34.34K   1 downloads

 

Which means that the armature, and the end of the slip-rings, have been rotating about different centres. End result is the armature fatigues and snaps at the bottom of the slip-rings.

 IMG_20240831_201342.jpg   37.09K   1 downloads

 

Game over. TudorCarParts-Dynamator has scored 2,500 points/miles and survived just six months of gameplay. TudorCarParts-Dynamator has not made it onto the leaderboard. Would you like to spend £189.95 to play again?

Edited by alpder, 01 September 2024 - 10:38 AM.

[Spider]

The 'PTO' is used as a Tacho Drive on cars.

Yes, it's a really bad design !

 

It's a crude coupling to allow for minor misalignment, but as you've come to the conclusion, in this arrangement, without a second support of the rotor, it's hardly going to last, especially as it's driven off a vee belt,,,,

[alpder]

Looking at pics of "Dynamator-"badged units on UK ebay now, some do have this take-off, and some don't. The ones with a black plastic cap on the back look exactly like mine and so they probably do have the shaft inside. Some have a blanked-off ally casting instead, so I guess no little shaft inside. I won't buy another Dynamator. But, anyone who does buy one would be well advised to take off the backplate and bin this little shaft, if they find it inside. Backplate removal is easy, and it doesn't disturb the main alternator bearing or the brush/reg pack.

 

But it's a GXE2211 for me. Getting to Minis-In-The-Mountains with a wrong-looking genny beats sitting for three hours at the Cofiwch Dryweryn layby while the AA deal with more urgent cases. (Tip: if you're gonna break down, don't do it in a safe location: because the yellow van with the flashy orange lights knows it doesn't need to rush.)

 

Never mind. I got to watch the Rali Ceredigion cars thundering past. And also got the pic I stopped for in the first place:

 IMG_20240831_132612_HDR.jpg   78.37K   0 downloads

[alpder]

When this Dynamator failed, I wrote to BB Classics (who supplied it retail via ebay 18 months ago). Also wrote to Tudor Car Parts themselves via their "contact us" form. Tudor Car Parts didn't reply. But BB Classics unexpectedly told me that they give a 2-year warranty and that I should return it to them for assessment.

 

So posted it back to BB Classics and, a week later, a new one turned up...

 IMG_20240912_140443.jpg   43.1K   0 downloads

 

[Spider]

Let's hope they have re-visited the design.

[alpder]

Well, I've got a regular alternator now in my Mk2. And my Mk1 is getting the full back-to-1963-spec treatment. So this Dynamator is going spare.

 

I'll have a look inside, but I expect the tacho drive is unchanged. Possibly they'll do a mod after examining my old one. More likely it is already in a skip.