Starting with the alternator off?

[PeterNSteinmetz]

What do people think of the pros and cons of this practice?

Discussion about this in this article about electrical systems - http://www.aeroelectric.com/articles/Alternators/Know_Your_Charging_System.pdf

 

[Ron Wanttaja]

My alternator won't work if it's on when I start the engine. I can cycle the switch and then it works, but now eliminate the middle-man and start with it off. B&C alternator and regulator on a C-85.

Ron Wanttaja

 

[PeterNSteinmetz]

My alternator won't work if it's on when I start the engine. I can cycle the switch and then it works, but now eliminate the middle-man and start with it off. B&C alternator and regulator on a C-85.

Any idea wha tis causing that?

 

[Ron Wanttaja]

Any idea wha tis causing that?

Nope. Probably some glitch in the B&C solid-state regulator. Wouldn't know how to trouble-shoot that, and the workaround is so simple there's no reason to try to figure it out.

After I installed the system, I was mighty peeved when the system failed to charge on the first start. Flipped the alternator switch off, then on, and it started working.

The first few flights repeated this process, until I decided to just roll with it and leave it off for start.


Ron Wanttaja

 

[rotorwrench]

What do people think of the pros and cons of this practice?

IMO, it really depends on your aircraft electrical system design whether there is any benefit. While in general is always best to reduce any loads during engine start, sometimes its not possible to reduce all loads. I think a review of the OEM start procedure, followed by a review of the aircraft electrical system, may reveal some benefit.

But based on my experience and knowledge, most alternator failures and wear and tear are not related to engine starting with the alternator switch on.