alternators regulators removed

robbymax

still need advice, i have given up trying to link two alternators in series but now i would like to know what voltage i would get if i removed the regulators from them. they are caterpiller 90 amp 24 volt and if i put a variable exciter voltage to the armiture any body done this ?

niel

Re: alternators regulators removed

maybe you should explain why you are trying to put them in series.

in removing a regulator the voltage will shoot way up and could exceed 100v.

interesting idea on the variable exciter voltage. care to elaborate?

waynefromnscanada

Re: alternators regulators removed

robbymax wrote: »

i would like to know what voltage i would get if i removed the regulators from them. they are caterpiller 90 amp 24 volt and if i put a variable exciter voltage to the armiture any body done this ?

The voltage you get will depend on both the RPM and the field (rotor) magnetic field intensity, which in turn depends on the current through the rotor winding.
I've done similar many years ago with a very small hydro system and a then "normal" GM automotive alternator that in those days had no internal regulator, for my cousin's camp.
Wired in a relay with it's coil powered by alternator output. When the alternator was at standstill and thus had no output, the relay disconnected the alternator output from the camp and redirected it to the rotor coil. As the alternator started to spool up, any and all output was redirected back to the rotor, reinforcing the residual magnetic field and at around 2000 RPM, the alternator would, with no external power, come to life. As the output voltage approached 12, the relay would pull in, letting an external regulator take control, and at the same time connecting the alternator output to his camp. Since the little turbine had limited power to turn the alternator, I installed a resistor (it's value long gone from memory) between the regulator output and the rotor coil to limit the load placed on the turbine by the alternator. There was no battery involved, and the alternator ran things directly, to a max of 200 watts.
This isn't exactly what you're thinking of, but regarding the variable exciter voltage, it was very similar, as I had to experiment to find which resistor value worked best for this installation. It was rather simple with hydro, as unlike wind, the mechanical power was constant.
You are going to find the alternator you have is going to really spin up before you get usable power as such alternators are not designed for low RPM output, and you'll also find it will demand considerable mechanical energy to spin it when the rotor is supplied with full voltage. It's going to be extremely difficult to manually control with varying wind speed, and if the rotor current comes from your battery, it will drain the battery whenever the wind drops off.
Good luck.

robbymax

Re: alternators regulators removed

niel wrote: »

maybe you should explain why you are trying to put them in series.

in removing a regulator the voltage will shoot way up and could exceed 100v.

interesting idea on the variable exciter voltage. care to elaborate?

I have given up with the series idea now I would like to remove the regulators and control the volts and amps by varying the armature voltage and the rpm of the engine all I want to do is charge a 48 volt battery bank

ChrisOlson

Re: alternators regulators removed

Actually, what you'll be controlling is field current with a outboard exciter.

It's hard to say what they'll make for max voltage - you'll have to apply 28 VDC power to the brushes on the slip rings and see what you get at a reasonable rpm. The limiting factor will be how much current the field coil on the rotor can take before it burns out. And I am not to optimistic about getting 60+ volts from them under load without rewinding the stators.

Cat does not make their own alternators - they're more than likely Leece-Neville/Prestolite units. And some of those are brushless too. I'd have to see a photo of one to know what you're working with.
--
Chris