It's looking like a matter of choice - as mentioned I have done keys first for over a year now and so far no problems
Stopping engine
- Thread starter Paulam
- Start date
That's not so, Don. When the regulator is shut off, and there's no field current, there will be no alternator output, except a tiny amount due to residual magnetism. But the alternator rotating does not mean it's producing power, you need field current to do that.
Makes sense and it would explain why I accidentally never damaged the alternator. I guess the old timer I learned the procedure from decades ago was not an electrical engineer but he sure knew it was OK.
It's not so hard to learn if you want to, you can learn it like building blocks. One way of looking at "zapping" things is to know you can't change the current in a circuit instantaneously, and Ohm's Law must always. be followed. So, if you have an alternator pumping current into a load and you suddenly disconnect it, the current is cut, and to satisfy Ohm's Law, (V-IR) the Voltage must suddenly increase - very high! This will exceed the withstanding.voltage of the diodes and burn them out.
That's why in older "points and condenser" ignition systems the condenser (capacitor) was there - to be charged up by the current when the points opened. Otherwise the Voltage would increase enough to arc, and burn the points.
None of us was born an electrician.
Like jviss said, we learned.These links could help you:
Electrical Systems 101 Electrical Systems 101
I'm an accountant (retired) I can build 20 year life of mine models but when it comes to electricity I leave it to the sparkies
Actually Don is correct. if this is the factory alt(leece-Neville) with key /on excite.. Once the alt is excited you can kill power to the excite wire and it will continue to work. the excite wire is only needed to boot it up..
Wouldn't that only be so if the key didn't also shut of the regulator? I'm referring to external regulators. I concede that I'm not familiar with all the internal regulator setups. (I thought Leece-Neville were somewhat archaic.).
That said, how will turning off the key with the engine spinning hurt a self-exciting alternator?
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 23,335
Really no more difficult than remembering which side of the line a debit or a credit are placed. It is all about perspective.
You just need to understand the rules. If it is not for you call an marine electrician, and chalk it up to 3 more billable hours.
You just need to understand the rules. If it is not for you call an marine electrician, and chalk it up to 3 more billable hours.
Okay, back to the ops question. Key or engine fuel shutdown first,. This morning I was out sailing and on the way back in while running the engine, I switched the key off. The alternator output immediately went to zero. I have a Balmar alternator with a 614 external regulator. The key controls power to the regulator and I assume that without a regulator the Balmar alternator cannot continue to produce power,. So, at least on my boat, it doesn't matter if you choose to turn the key off first.
when you say alternator output went to zero - are you seeing that from the volt gauge on the panel?