• If you like what you see here and your interests are compatible with our 30,000 other users, Welcome. Fill out the registration form with your interests, your real name (seen only by moderators) and your city, state or country. Be certain that you have spelled your email address correctly! Your account is then manually checked and approved.

Mecc Alte Spa Generator

Charlin

Registered
Yeah I know what you mean. I don't know anything about repairing generators, but I've worked on a lot of stuff that didn't work after doing
the obvious.

Do you think changing the VR would be worth a shot? Or is this not the issue of a faulty VR at all? The Mecc Alte SR7 regulators are expensive.
I wouldn't just throw that kinda money at it in hopes it worked. But I have found some knock off SR7 regulators around $60.00. That I would
take a gamble to see if it repaired it, and then replace that one with the brand one if it repaired it.
 
Last edited:

Vanman

Subscriber
Last Subscription Date
06/10/2020
This is a head scratcher for sure. But here are a couple of thoughts.

I wonder if this generator has a small permanent magnet to ensure that the machine builds up when first started? That would explain the relatively high voltage with no exciting current on the exciter field. If so, I would *guess* that the magnet is in the exciter field, and that means that the polarity of the current used to separately excite for testing matters.

Are you sure you applied the 12 volts to the exciter field with the correct polarity?

It may also be worthwhile to try a test with 24 volts on the exciter field, after ensuring that you are using the original polarity as when the machine was working.

I also suspect the AVR- those almost always seem to be the problem- but I would still want to see the generator working well while separately excited first.

Keith
 

Charlin

Registered
I'm pretty sure I had the polarity correct. The negative wire from the exciter that goes to the AVR is blue. When I had the leads
from the battery in my hand, I said to my self black to blue, just so I didn't screw up. Now that doesn't mean I didn't, I've done stranger stuff.

I didn't see anything in the manual about a magnet, the one that came with it or I have looked up online. I will go back through those and look.
My manual stated to put a 30 ohm resistor inline on the positive lead when exciting. I did that even though it didn't seem to drop the voltage
from the battery much at all, so I'm not sure what that was for. I will try exciting again tomorrow just to be sure.

As for using 24 volts to excite, I don't know anything about this stuff. I don't know if that would be too much or not. Have you done it that way?
 

Charlin

Registered
I went out little while ago and put it back together and to excite it again. It is acting different now. When I started it I had 60 volts on the main
terminals. That is up from 44 volts prior to me doing those tests. 48 volts DC on the the AVR at the exciter terminals which is up from I think 33.
0 DC voltage on the exciter terminals with the blue-yellow wires connected.

I disconnected the blue-yellow wires and excited them with 12 volts again, and this time the engine rpms dropped, and the main output went
down to 22 volts. I either caused a new problem or exacerbated the current one.
 

Top