Strange Alternator behaviour

Here's a little bit of useless information for younger OP. Until 1960 all motor vehicles had generators (dynamos). Then in 1960 Chrysler brought out the Valiant with an alternator. Their claim to fame was that alternators produced more current at lower RPM. Within a few years all automobile manufacturers had followed suit.

Now I'm waiting for some smart-aleck to tell me it wasn't Chrysler at all as the 1921 Willys Knight (or something) had an alternator!!:)
 
Last edited:
Alternator (automotive) - Wikipedia, the free encyclopedia
en.wikipedia.org/wiki/Alternator_(automotive)‎
The first car to use an alternator was an unusual system fitted to early Model T Fords. This entirely AC system was first used solely to power the trembler coil ...


Geez....... I can't win:rolleyes:
 
VicS said:
good point about the pulley sizes and tacho calibration although I'd expect some adjustment to be possible.
Click to expand...

The only adjustment I have seen Vic is digital rather than analogue. In other words number of pulses per rev or such like. This usually covers the requirement of the engine manufacturer who normally fits a pulley size to ensure a set number of pulses per crankshaft rev. I have never seen one that can change by small increments. I haven't seen everything however and you may know better....
 
If we are having a pedantic competition here I would point out that I had a 1906 Ivory Calthorpe motorbike once with a brushless alternator rotor with stationary coil mounted on the end of the crankshaft (motorbikes are motor vehicles too) but I see you live in Western Australia and I don't think convicts had motorbikes so you wouldn't be expected to know that....... :-)
 
My VDO tachometer works off the alternator. I will ensure the alternator pulley is the same size as the crankshaft pulley. There are 5 switches on the back of the gauge which would give a broad range adjustment but then (according to the instructions) the instrument can be finely adjusted.
 
MJ24 said:
Mine was the same...

Brushes needed changing.

Took it to automotive electrician. Done in a flash and now back to normal..

Mj
Click to expand...

The OP says. "I have just fitted a prestolite 90A alternator......"

If he means he has just fitted a new Prestolite alternator worn brushes are not the reason. Possibly they are if he has fitted a well used secondhand unit without having it overhauled first.
 
boatmike said:
If we are having a pedantic competition here I would point out that I had a 1906 Ivory Calthorpe motorbike once with a brushless alternator rotor with stationary coil mounted on the end of the crankshaft (motorbikes are motor vehicles too) but I see you live in Western Australia and I don't think convicts had motorbikes so you wouldn't be expected to know that....... :-)
Click to expand...

Of course every generator of current from rotation is an alternator. It is all a question of how if at all DC is produced from the ac naturally produced. So here we get lost in the various meanings of "alternator". This should perhaps be restricted to a generator designed to deliver AC. ie 240v 50 hertz. However the name is commonly used to describe the generator on modern engines. The original style was an alternator with syncronous brush pick up of Dc from the produced AC. generally known as a generator or even dynamo. As Coopec says in oz the first car to appear with what we now often call an alternator wasa Chrysler in 1966. This was possible because of the invention and availability of high current silicon diodes.
The design of the rotor is such that it can operate at very high RPM without flying apart. The field coil is axial on the shaft and it is iron pole p[ieces that direct the magnetic field to the circumference. Compared to the windings on a generator (dynamo) which are larger and mounted radially to the shaft so much more susceptible to centripetal forces.
So because the alternator could be run at higher speed it was driven faster by having a smaller drive pulley. This is what enabled the alternator to charge at idle engine speed.

And just to confuse things people on this forum seem to want to use the term "generator" for a 240v AC 50 herts alternator. I try to keeep up with the language barrier.

Now regarding convicts in West Australia. The colony was originally set up without convicts by free settlers. It was only when the settlement languished before the discvovery of gold that convicts were specifically requested to help build infrastructure and help the economy. Actually very few convicts came to Perth. Motor cycles did however come from early on. and now economically we are doing OK now thanks. olewill
 
You must log in or register to reply here.

Other threads that may be of interest

Jon magowan
White Smoke from my Engine
Replies
11
Views
440
Ian_Rob
I

Share this page

Top