If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
Aaron Coolidge wrote:
: Cory, it sounds like this is the 2 starter contactor situation like I : mentioned. The jumper wire he's referring to goes between the solenoid and : the PM motor itself. I found a link to the graphic on Skytec's web page. One that says, "This is for certified aircraft, this is for experimental." The experimental version is more like an automotive setup... starter switch runs solenoid. The certified version switches the main power. : I liked your idea about a freewheeling diode, but you'd need a series diode : on the input to the PM motor too (to keep the voltage in the PM motor to : freewheeling diode circuit). I wouldn't worry about the current handling : capacity here, 600 A diodes are easy to get, but the Vf of the diode would : probably be like 1.0V. When cranking the voltage at the PM motor is probably : only about 6 or 7 V (piper uses a 6V contactor for the starter) so 1V : lost in the diode is a large fraction of the available power! : -- : Aaron Coolidge I'm going to look into modifying the system. By running the jumper wire from the firewall starter relay's *input* to run the starter solenoid as well, that would accomplish the same thing. A big current diode could then free-wheel the motor by itself (no need to be in series... use the starter solenoid contactor for that). I've contacted Skytec to see if they've every field-approved such a modification. I understand why they don't do that for all the installations. It would have to be tested/certified on every airframe/engine combination. If they rig it just enough to work adequately as the one they replace, they can PMA it and it automatically works on everything. It may not be optimal, but it works. We'll see how it goes. -Cory -- ************************************************** *********************** * Cory Papenfuss * * Electrical Engineering candidate Ph.D. graduate student * * Virginia Polytechnic Institute and State University * ************************************************** *********************** |
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Starter Questions | Aaron Coolidge | Owning | 4 | June 30th 04 02:52 PM |
Stuck starter solenoid? | Paul Lee | Home Built | 4 | April 16th 04 02:58 PM |
LIghtweight starter recommendations for PA24-250? | Chris Kennedy | Owning | 4 | April 8th 04 12:01 AM |
Starter selection -- seeking input | [email protected] | Owning | 3 | April 5th 04 12:43 AM |
Sticking Starter | Wayne | Owning | 5 | September 2nd 03 07:26 PM |