[simpits-tech] N1 & N2 Gauges

[Matt Bailey]

It's pretty straightforward. You can do this with just an Arduino and one of the cheapo L298N H-bridge boards on ebay. I did it very crudely and easily, and ended up with poor control below about 30% RPM (on my particular indicator), but totally smooth response above that. Another fellow I know adapted a sine wave approach that used the Arduino's PWM channels, which gave good control all the way down to 0.
Check out the overhaul manual for your indicators. You're basically building a brushless speed controller.
Matt


Sent from my Sprint Samsung Galaxy S® 6.-------- Original message --------From: "David C. Allen" <dca911t at gmail.com> Date: 8/7/2017  1:04 PM  (GMT-06:00) To: Simulator Cockpit Builder's List <simpits-tech at simpits.org> Subject: [simpits-tech] N1 & N2 Gauges 
Hello
I was wondering if anyone has used a Arduino to get the N1 & N2 gauges operational?

From the information I have found there is a 3 phase generator for the N1 & N2 mounted on the engine. The gauges have a 3 phase motor connected to a flux coupling (like is used in a mechanical speedometer) to drive the pointer. Once the engine is operating the N1 & N2 are self powered.

I found a chart that lists the generator RPM vs Indicator % RPM

0 gen = 0 %RPM
840 gen = 20 %RPM
2520 gen = 60 %RPM
4200 gen = 100 %RPM

So a question on frequency of the generator, would vary with generator RPM 

Looking at one leg of the generator 

0 gen = 0 Hz = 0 %RPM
840 gen = 14 Hz = 20 %RPM
2520 gen = 42 Hz = 60 %RPM
4200 gen = 70 Hz = 100 %RPM

Just looking for ideas

David
N9070U 737-222

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.simpits.org/pipermail/simpits-tech/attachments/20170807/30ea9694/attachment.html>