Low Generator AC output

by Detlef Heun in 912 / 914 Technical Questions 11 years ago

Hi!
A friend has problem with the 914 charging system.

Some hours ago he mentioned a lower than normal charging voltage and today the red light was burning.

I checked the regulator output on B+ and got only the battery voltage.

I checked the yellow to yellow wires of the generator and got 0,9 OHM. A little bit outside of the range from the manual that says 0,1 - 0.8 Ohm. It is not a calibrated OHM meter!!!

Yellow to Ground infinitive.

The AC voltage output is at idle low. 11 V instead of 18-20 V
At 2000 RPM the Voltage is 15 V
At 4000 RPM 30 V

The regulator ground to ground is OK.

Do you have an idea why the Generator AC output is so low at idle and 2000 RPM

Thanks in advance
Detlef

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Re: Low Generator AC output

by Rob Seaton » 11 years ago

Rob Seaton

3 1.32k 240

The AC volt varies a lot; at 2000rpm it is approximately 16v but it can be as low as 10v.
It is more likely you have bad regulator.
Rob

Thank you said by: Detlef Heun

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Re: Low Generator AC output

by Przemysław Wiśniewski » 11 years ago

Przemysław Wiśniewski

65 247 3

Hi, can you let me know, what was bad? I have similar problem.

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Re: Low Generator AC output

by Detlef Heun » 11 years ago

Detlef Heun

1 1 0

Hi!

I replaced the regulator and cleaned all the connections and everything was fine.

Hope that works for you.

Greatings from Albuquerque, New Mexico

Detlef

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Re: Low Generator AC output

by Przemysław Wiśniewski » 11 years ago

Przemysław Wiśniewski

65 247 3

Thanks, I'll check :)

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Re: Low Generator AC output

by Ken Berger » 11 years ago

Ken Berger

3 6 0

Read the above post and currently have a similar problem.

I have been charging normally and then went flying today and noticed that my 914 Rotax seemed to only be producing about half the amperage as previous. I determined this by comparing the excess amperage on my Dynon "amps" readout (same load) when was indicating over +5 previously and more at higher revs, but today was 0 to 2 no matter how high the revs were.

According to my 914 install manual there should be about 10 amps being generated at 2,500 rpm and about 20 amps at takeoff full power. My memory was that the unused "extra" amps which were not used showed on the "amps" indicator, which should have been a readout of about 5 amps today, but was at or close to 0.

What goes? Time for a new regulator?

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Low Generator AC output

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