Topdog Posted September 30, 2017 Share Posted September 30, 2017 (edited) I have bought a small gas turbine apu just to run up for giggles but in place of the starter there is a generator. I want to know if I feed this electricity will it turn? I cant remember how to post a photo but there are 4 terminals which are two obvious pairs and the data plate shows Rating-----Ground----------Flight KW---------2.2--------------4.4 volts rms----83--------------115 Phase------single----------single HZ----------192----------220/400 RPM-----min 5760-----6600/12000 Any help much appreciated as the fitting and drive pinion is correct for the turbine. On another point, is the ignitor box critical on polarity? The feed is 24v but I have no way of telling which is pos and which is neg apart from one runs to ground - but I don't know if an aeroplane (HS125) is pos or neg earth and I don't want to blow the box by getting it wrong. Many thanks Dave Edited September 30, 2017 by Topdog Spacing of columns Quote Link to comment Share on other sites More sharing options...
andym Posted September 30, 2017 Share Posted September 30, 2017 Silly question perhaps, but how do you know it's a generator rather than a starter? Some more info on the APU would help, too! Andy Quote Link to comment Share on other sites More sharing options...
Topdog Posted September 30, 2017 Author Share Posted September 30, 2017 I would post pics if I could remember how to do it Andy. Its a Garrett GTCP-30-92C. Kind of looks like an overgrown turbo from a car ie round snail type engine rather than long straight through flow. The generator is marked Lucas Aerospace Air Cooled A.C.Generator but the fitting and splined shaft is an exact fit for the engine and I was given it by the engineer who I got the engine from as a generator that I might get to work as a starter as he did not have a proper starter for it. Quote Link to comment Share on other sites More sharing options...
Topdog Posted September 30, 2017 Author Share Posted September 30, 2017 (edited) I have no way to spin the genny at speed to see if it produces current. Each pair of contact shows continuity and does not carry across to other pair. There is no reading on an analog meter for anything (volts, amps, DC, AC) if I spin by hand. The next thing to try is some sort of bodge to spin higher speed which might involve an electric drill or lathe - probably not a good idea....... or just to shoot some current into it starting with 24v and then 240v and have gloves on and fire extinguisher nearby. Edited September 30, 2017 by Topdog spelling Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted September 30, 2017 Share Posted September 30, 2017 It sounds like this generator maybe a Dynastart type which has the ability to be used as a starter then once running be a generator. I believe some small gas turbines use this system. Quote Link to comment Share on other sites More sharing options...
lowfat Posted September 30, 2017 Share Posted September 30, 2017 (edited) That generator is a 3 phase 115/200 vac 400hz generator. I doubt it will be what you want. does it have 6 large output terminals and 3 or 4 smaller terminals? Typically a gas turbine engine with a starter/generator sytem is DC 28 volts and uses brushes. The generator has a control box that allows it start the engine then when a specific speed is reached it becomes a generator. http://www.gasturbineworld.co.uk/garrettgasturbines.html Does it look like the silver cylinder in the picture? that is what a stater genny looks like for this engine. Edited September 30, 2017 by lowfat Quote Link to comment Share on other sites More sharing options...
Topdog Posted September 30, 2017 Author Share Posted September 30, 2017 That generator is a 3 phase 120 vac 400hz generator.I doubt it will be what you want. Typically a gas turbine engine with a starter/generator sytem is DC 28 volts. The generator has a controll box that allows it start the engine then when a specific speed is reached it becomes a generator. Thanks lowfat. It states single phase on the plate. Will it run if I stick mains current into it? Quote Link to comment Share on other sites More sharing options...
Topdog Posted September 30, 2017 Author Share Posted September 30, 2017 It sounds like this generator maybe a Dynastart type which has the ability to be used as a starter then once running be a generator. I believe some small gas turbines use this system. Thanks Richard. It should be fitted with a starter generator but I suspect that my item is not the proper one for it. Quote Link to comment Share on other sites More sharing options...
lowfat Posted September 30, 2017 Share Posted September 30, 2017 No it wont run if you put mains in it. If its single phase its rated to 115 volts and 400Htz. Mains is 240 volts and 50 htz. I added a picture to my first post is it the same The starter part of it will be using 28vdc. Aircraft battery power. Quote Link to comment Share on other sites More sharing options...
lowfat Posted September 30, 2017 Share Posted September 30, 2017 Aircraft are negative earth. please be careful with the ignition system it will kill you if you make a mistake. always leave it 30 minutes after you remove power before you touch any part of the ignition system especially the igniter lead. The box should have a internally resistors which bleed the 40,00 volts to earth . Its not like a car coil pack this is designed to work at altitude so the spark is very meaty. Quote Link to comment Share on other sites More sharing options...
andym Posted October 1, 2017 Share Posted October 1, 2017 If the generator has two sets of two terminals then I'd suspect one set to be the field windings and the other the output. The field windings produce the magnetic field, without a dc voltage supplied to them nothing will happen. To run as a motor (assuming it's capable of doing so) you'll need to supply dc volts across one set of terminals and ac across the other set. You really need to find some more info or you're in danger of damaging something, including yourself! Andy Quote Link to comment Share on other sites More sharing options...
Chris Hall Posted October 1, 2017 Share Posted October 1, 2017 Some info which maybe of use- http://www.gasturbineworld.co.uk/garrettgasturbines.html https://aerospace.honeywell.com/en/product-listing/auxiliary-power-units Quote Link to comment Share on other sites More sharing options...
Topdog Posted October 1, 2017 Author Share Posted October 1, 2017 Aircraft are negative earth. please be careful with the ignition system it will kill you if you make a mistake. always leave it 30 minutes after you remove power before you touch any part of the ignition system especially the igniter lead. The box should have a internally resistors which bleed the 40,00 volts to earth . Its not like a car coil pack this is designed to work at altitude so the spark is very meaty. Thanks mate - GOT IT - I will be very careful. Should I ground spike it when running? Quote Link to comment Share on other sites More sharing options...
Topdog Posted October 1, 2017 Author Share Posted October 1, 2017 Some info which maybe of use- http://www.gasturbineworld.co.uk/garrettgasturbines.html Cheers Chris - That's mine, the top one. Quote Link to comment Share on other sites More sharing options...
Topdog Posted October 11, 2017 Author Share Posted October 11, 2017 Fuel solenoid and ignite box both work well Quote Link to comment Share on other sites More sharing options...
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