TUL: 5746 E Apache St. Tulsa, OK 74115
FXE: 1072 NW 53rd St. Fort Lauderdale, FL 33309
07 Sep

Overheated Aircraft Starters

Hartzell Engine Technologies has started an informational series regarding their products. The first entry in the series is a video entitled “Understanding Your Aircraft Starter’s Duty Cycle”. The video is a little over three minutes long and provides information of the duty cycle of different starters. The information provided is great and should be used by all pilots. However, if you are like me you would like to know what is happening in the starter when these guidelines are not followed. The results of overheating your starter will definitely lead to frustration and the purchase of a new starter.

The first thing to know about aircraft starters or starters in general is that they are very powerful components of your ignition system. The electric motors are able to turn at turn at such a rate that they can get much larger piston engines to fire. That is impressive to think when considering how much smaller the starter is to your typical aircraft engine. In fact, if you were to run a starter with no engagement to an engine the part will literally tear itself apart because it is meant to only be used with resistance put on it. Now when the starter is on an aircraft engine and is run too long this will cause the unit to be overheated and the armature to burn. The starter operates by spinning 180 degree opposed brushes on a circular series of commutator bars which completes a circuit and induces a magnetic field in the armature windings. The armature windings are joined at each end to the commutator bar byway of a soldered connection. The powerful nature of the starter generates heat in the armature windings. If the starter is over operated or not allowed to cool the armature heat is transferred through the windings into the soldered points which will melt. The melting of the soldered points causes the armature to short circuit and in some cases the armature windings will also melt and fuse together.

If you are ever having issues starting, try to remember your duty cycle as you continue to try to get the engine to fire. If necessary, contact us or the company you purchased the part from to troubleshoot your system. It is better to spend some extra time to have the issue corrected properly than to be hasty and compound the problem.