Aircraft Systems: What is an Aircraft Tachometer Generator? 

Your aircraft’s electrical system is comprised of several parts, including a battery, generator or alternator, and an electrical bus to distribute electrical power. In this blog article, we’re going to explore your aircraft’s tachometer system, namely the tach generator. We’ll cover its different components, as well as repair tips and specific brands we work on. 

What is a Tachometer System? 

Your aircraft’s tachometer system is found on most general aviation aircraft and, according to industrial electronics, is a small three phase AC generator connected via a mechanical link to engine accessory gearbox.  

So, how does it work? The AC generator tachometer consists of a permanent magnet that is rotated inside stator windings wound in a three-phase star configuration. Three stator outputs are connected to the stator windings of the motor. As the engine turns, the permanent magnet induces currents in the stator windings. The three-phase output induces a rotating field in the motor stator windings. 

Check out this image for a visual on how the tachometer system works⤵️ 

Tach Generator Repair, Maintenance, and Overhaul 

At AAI, we supply tach generators but don’t work on them. However, we can still offer advice and tips on tach generator replacement or repair.  

Insider Tip: 

If you have RPM fluctuations or no RPM indication, chances are you have a faulty tach generator. This could be a simple electrical connection fix or a major problem requiring repair or replacement of the tach generator. 

What Components is a Tach Generator Made Of? 

A tach generator consists of several different components: 

➡️ Permanent magnet 

➡️ Windings 

➡️ Rotor Shaft 

➡️ Housing 

➡️ Cannon Plug 

Where Can You Find Aircraft Tach Generator Repair Shops? 

AAI supplies and manages repairs on brands like Electro Mech, General Electric, Kollsman, Lear Siegler, and TRW Globe. We understand that when you can’t find the parts you need, the problems multiply. You send in your plane for routine maintenance and expect to have it back in a week. But inspections turn up several parts that need to be replaced, which could take weeks or even months. What now? 

The entire process of locating, ordering, and receiving certified aircraft accessories is a huge headache. 

Uncertified, untested parts are all over the internet, but do you really want to risk your safety for convenience? Certified replacement parts can take a ridiculously long time to ship – sometimes months – and the cost can be absurdly high. 

Unless you shop with AAI. 

We’ll help you avoid the delays and headaches, and instead get certified, safe, and tested aircraft accessories so that you can fix your aircraft and get back to flying. 

1. Call AAI  

2. Get a quote  

3. Fix your plane and fly  

Find the parts you need and get back in the air, fast. 

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