Alternator slow to wake up

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Diamond_Dan
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Re: Alternator slow to wake up

Post by Diamond_Dan »

Had my annual done at a different shop this year to take care of the wing spar A/D, GWI, and some squawks. Mechanic there didn't think anything of it so I'm not going to worry about it. Makes sense to me that the regulator would require a minimum voltage from the alternator to prevent an over-current situation with various components.
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Charles
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Re: Alternator slow to wake up

Post by Charles »

Any chance you could borrow a regulator from a sister plane to test it?

In my plane, the alternator cuts out below 950-1000rpm. I believe this is perfectly normal.
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Diamond_Dan
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Re: Alternator slow to wake up

Post by Diamond_Dan »

There are a few others on the field but we are all private owners. (I would refuse if somebody asked me)
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Davestation
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Re: Alternator slow to wake up

Post by Davestation »

What is your idle RPM? I wonder if the 2 minute "warm-up" is less about actually warming up and more about the idle increasing in conjunction. Have you bumped the RPM to 1000 right at engine start with no change?

A brand new alternator will charge well below 1000 but depending on the battery state may not reach 28V. If the voltage doesn't pick up at all until over 1000 that's generally a sign that it's worn out.
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Diamond_Dan
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Re: Alternator slow to wake up

Post by Diamond_Dan »

Davestation wrote: Mon Oct 31, 2022 3:31 pm What is your idle RPM? I wonder if the 2 minute "warm-up" is less about actually warming up and more about the idle increasing in conjunction. Have you bumped the RPM to 1000 right at engine start with no change?

A brand new alternator will charge well below 1000 but depending on the battery state may not reach 28V. If the voltage doesn't pick up at all until over 1000 that's generally a sign that it's worn out.
I'll check next time to see when it comes to life and at what RPM.
What is the "2 minute warm-up"?

I do have a freshly rebuilt alternator (2X) and both times behaved the same way.
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Re: Alternator slow to wake up

Post by Davestation »

You said it takes 2 minutes to wake up but I didn’t know if that was as idle or what
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