ChangDriver
Joined: 15 Sep 2007
Posts: 266
|
 Posted: Thu Oct 22, 2009 6:44 am Post subject: p-lead signal conditioning or tach gen usage |
 |
|
Bob:
My application is a russian radial engine and I am trying to use the tach input of an EFIS system in the aircraft. The EFIS expects a nice square wave from a Hall Effect sensor. However, I cannot mount a Hall effect sensor on the Russian mags as there is no port to do so and even if there were, the threads would be metric pitch.
The tach gen is a three phase AC generator. The connector on the tach gen is three pins so it is likely Y-wound and uses the case as neutral. According to specs on the engine, the tach gen turns at half of the engine rpm. What I see is the following:
1) I can use a single phase of the tach gen as you proposed but I will then only get one-half pulse per revolution of the engine since the gen turns at half the engine rpm. I was thinking of doing full wave rectification of the signal to get back to one pulse per revolution.
2) I could condition the p-lead signal and tell the EFIS that there are 4.5 pulses per revolution. However, I don't know how to condition the signal properly. This method would provide no engine RPM during a mag check but I'd be OK with that.
We are putting a scope on one phase of the tach gen output and the p-leads tomorrow. I'll take a picture of the scope as this will help.
Thanks,
Craig
PS - bought your book and it is excellent. Thanks for that and all your help to us with experimental aircraft!
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
