Signs of Generator Failure

[RJS]

Hi

Just curious, when a generator starts to fail, does the output gradually start to decline over time or does it just up-and-quit all at once?

Reason I ask is that although output is understandably low at idle, I have noticed lately there isn't even enough output to keep the temp and fuel gauges reading accurately (both dip lower). But, once I bring the revs up, the gauges read correctly. I don't recall the gauges behaving like this before. Any one seen this before?

Thanks

Bob

 

[TR3driver]

More likely IMO your voltage stabilizer isn't doing it's job. It should keep the gauge reading constant down to a system voltage of 10 volts or so. And even with the generator totally failed, the battery voltage shouldn't go that low until it's too run down to start the car.

Another possibility might be a bad connection or high resistance that is reducing the voltage supplied to the VS.

While there are problems that can reduce the generator's output, they usually lead to the generator failing totally in fairly short order. At anything above a fast idle, the generator's output current is limited only by the control box, so if one or two windings are not working, it tends to overload the other windings and cause them to quit as well.

 

[AltaKnight]

I agree, voltage regulator or poor grounding

 

[RJS]

Thanks Randall, thanks Graham,

I hadn't considered that and I'll definitely start investigating those items first. A generator is a very simple component so it makes sense it is the least likely to be the culprit here.

Bob

 

[trrdster2000]

Bob, your stabilizer is located in the passenger footwell, top right, just above the carpet. They moved it with the start of the TR6 or maybe the tr250, not real sure..

Wayne

PS Save you tearing the dash out.

 

[RJS]

Cheers Wayne,

I found it on p.363 of my Workshop manual. It states VS is located under the right side fascia. The accompanying photo show it next to the accelerator pedal so, obviously a RHD car. Definitely beats going up behind the dash though.

Also, my "How to Repair Brit Cars" manual as well as the online Tech Sheet for the new solid state VS made by Moss confirms wacky gauge behavior is nearly always due to a faulty VS or connections thereto. So, I am cautiously optimistic (?) this is a simple fix. Thanks guys for pointing me in the right direction.

Bob

 

[TR3driver]

Bob, your stabilizer is located in the passenger footwell, top right, just above the carpet. They moved it with the start of the TR6 or maybe the tr250, not real sure..

Oops! My mistake, sorry for the bad info!

Somehow, I had it in my head that it moved to the speedo when they converted to negative ground (ie start of TR4A) ... I plead senior moment.

 

[KVH]

I looked up in the passenger footwell and there it is in my 4A. I'd thought the Voltage Stabilizer had been moved, but I was wrong.

In my '62 TR4, which was a negative ground, I went through two stabilizers in 5 years.

Was there a problem with the early TR4 electrical system?

Also, if my car was a '63, did someone convert it to negative ground?

I always had hot wires, melted wires, shorts and issues. Not so on my 4A.

[OT: SOMEONE PLEASE BUY THAT EBAY TR4 IN CALIFORNIA AND KEEP IT IN THE GOOD OLD USA!!!]

 

[MDCanaday]

When in the rare case a generator lasts a long time,you may find that it acts funny in its old age due to worn brushes.The springs dont hole the worn brushes as tightly to the comutator,and it makes less of the smoke needed to keep the darkness at bay.If you put in new bits be sure to clean lube and tighten as you go back with a fresh new fan belt to make it all sweeet!!
MD(mad dog)