MCI 9 6V92 generator issue

[RickB]

Thanks for the help/info,

We're figuring a PO did a repower w/o the air tensioner or a belt driven alternator/generator with an air tensioner.

Still doesn't explain the intermittent gen light turning on and off after it has sufficient air in the system.

Rick

[bevans6]

Mine will flash the no-gen light if the rpms drop for a second, and the air switch and/or relay could certainly be failing. 

Brian

[Hartley]

No-Gen - Issues..

Although there wasn't enough info about what kind of electrical loads are present there have been issues with the No-Gen light cycling on a number of coaches(conversions)
Where the OTR heat and air have been removed.

Most OTR systems have a large electrical load when the blowers are running which can be around 140 amps or so depending on the original systems.

On coaches that still have the 300 amp Alternator systems with the older style voltage regulators but no longer have that large electrical demand, The charging system could sense a full charge on the batteries and shut down the alternator output enough to make the no-gen light come on. ( Or flicker!! ).

The regulator will cut off the power to the field on over-voltage conditions or under current conditions. The only real solve is to find a newer style voltage regulator that can handle charge management better. Or add a huge electrical load.

Or change out the 300 amp alternator for a smaller belt drive version more capable
of handling the reduced demand where only the running gear and coach primary power is required.

I have seen the no-gen issue on several conversions and a couple of my own buses that had the OTR systems removed. I did change a circuit board in one regulator and reset the charge voltage a little lower and the problem went away. I also had a bad battery on another bus that created havoc with the system voltage but changing the battery seemed to solve that problem.

My MC9 has the stock electrical system. I have had the no-gen light issue but discovered that it was an air pressure switch problem. Not really an alternator issue but after tracing the way the no-gen light is hooked up there are a couple of different things that may cause the light to come on. One is air pressure and the others are switched inputs from other safety systems built into the wiring.

I also changed from 8D batteries to 4-group 31 batteries which helped stabilize the electrical system and made starting much better.

Just a continued thought....

[Slow Rider]

My not gen light will come on when my batts are topped off.  I just flip on my running lights and the problem goes away....

Frank