Kitfox Aircraft Stick and Rudder Stein Air Grove Aircraft TCW Technologies Dynon Avionics AeroLED MGL Avionics Leading Edge Airfoils Desser EarthX Batteries Garmin G3X Touch
Page 1 of 2 12 LastLast
Results 1 to 10 of 11

Thread: Regulator?

  1. #1

    Join Date
    Jun 2013
    Location
    Spokane, Wa
    Posts
    120

    Default Regulator?

    Hi guys, Early Rotax 912 UL 80 hp, just installed a MGL Extreme and I keep getting over voltage alarms- voltage varies from 13.5 all the way to 16.7. I changed the regulator with no difference. My question is what is normal? My friends Rotax does not vary any where near this much. My problem is this might be normal for my plane, I just have never had instrumentation to know. Thanks-

  2. #2
    Senior Member PapuaPilot's Avatar
    Join Date
    Nov 2013
    Location
    Nampa, Idaho
    Posts
    1,225

    Default Re: Regulator?

    No that doesn't sound normal. A regulator usually holds the voltage within 0.1 volts.

    I don't know your system, but typically 12 volt systems will regulate around 14.0-14.5 volts.

    Do you have any intermittent loads like flashing lights, strobes or wig-wag that draws high amps? That could be a cause.

    Can you adjust your over voltage alarm threshold on the MGL? If so try increasing it to 16 volts or higher.

    Does your electrical system have a big capacitor in the charging system? It could be a cause if it has gone bad.
    Phil Nelson
    A&P-IA, Maintenance Instructor
    KF 5 Outback, Cont. IO-240
    Flying since 2016

  3. #3

    Join Date
    Jun 2013
    Location
    Spokane, Wa
    Posts
    120

    Default Re: Regulator?

    Quote Originally Posted by PapuaPilot View Post
    No that doesn't sound normal. A regulator usually holds the voltage within 0.1 volts.

    I don't know your system, but typically 12 volt systems will regulate around 14.0-14.5 volts.

    Do you have any intermittent loads like flashing lights, strobes or wig-wag that draws high amps? That could be a cause.

    Can you adjust your over voltage alarm threshold on the MGL? If so try increasing it to 16 volts or higher.

    Does your electrical system have a big capacitor in the charging system? It could be a cause if it has gone bad.
    Thanks for the reply-

    Basic system with no lights, just basic radio,intercom, gps, MGL and transponder. I do not believe it has a capacitor in the system- but I am careful not to kill the master before I shut the engine off. I'm wondering if there is something wrong with my sense wire, anything special I should look at impedance wise on that wire?

    Thanks again,

    Scott

  4. #4
    Senior Member PapuaPilot's Avatar
    Join Date
    Nov 2013
    Location
    Nampa, Idaho
    Posts
    1,225

    Default Re: Regulator?

    Again, I don't know your system. Do you have a schematic?

    The sense or field wire could be possibilities. It could also be a problem with he alternator.
    Phil Nelson
    A&P-IA, Maintenance Instructor
    KF 5 Outback, Cont. IO-240
    Flying since 2016

  5. #5

    Join Date
    Jun 2013
    Location
    Spokane, Wa
    Posts
    120

    Default Re: Regulator?

    Found it. Turned out to be a loose screw on the back of a circuit breaker(the one that is hooked to the sense wire). Amazing how a loose screw can cause such huge deviation! Thank you PapauPilot for your input-

    Scott

  6. #6
    Senior Member efwd's Avatar
    Join Date
    Jun 2015
    Location
    Yorba Linda, CA
    Posts
    2,817

    Default Re: Regulator?

    Sweet! If only all the electrical Gremlins could be resolved this quickly.
    Eddie

  7. #7
    Senior Member jiott's Avatar
    Join Date
    Jun 2010
    Location
    Portland, OR
    Posts
    2,959

    Default Re: Regulator?

    I still think you need to install a large capacitor like all the Rotax installation schematics show.
    Jim Ott
    Portland, OR
    Kitfox SS7 flying
    Rotax 912ULS

  8. #8

    Join Date
    Jun 2013
    Location
    Spokane, Wa
    Posts
    120

    Default Re: Regulator?

    Quote Originally Posted by jiott View Post
    I still think you need to install a large capacitor like all the Rotax installation schematics show.
    Definately a good idea, I agree.

  9. #9
    Senior Member Slyfox's Avatar
    Join Date
    Dec 2008
    Location
    felts field, spokane
    Posts
    1,327

    Default Re: Regulator?

    scott. one thing you need to know about the rotax regulator. they do not like to be shut off when the engine is running. do not, I repeat do not check the alternator like we were taught in flight school. just look at your voltages and say, yup it's working. turning off the field for the alternator will kill the regulator. take care.
    steve
    slyfox
    model IV 1200-flying
    912uls
    IVO medium in-flight
    RV7A-flying
    IO-360
    constant speed prop

  10. #10

    Join Date
    Jun 2013
    Location
    Spokane, Wa
    Posts
    120

    Default Re: Regulator?

    Quote Originally Posted by Slyfox View Post
    scott. one thing you need to know about the rotax regulator. they do not like to be shut off when the engine is running. do not, I repeat do not check the alternator like we were taught in flight school. just look at your voltages and say, yup it's working. turning off the field for the alternator will kill the regulator. take care.
    Thanks Steve- appreciate the input

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •