Andrew T Posted January 21, 2005 Report Posted January 21, 2005 Panic phone call from MrsT yesterday afternoon to say that the Galaxy had died while she was on her way to the school. Luckily it did it on the only straight bit of road for miles around and someone from the village stopped within moments to give her a lift. Splendid fellow that she is, she had already diagnosed electrical failure, so I went to retrieve it armed with a charged up Battery. Battery on the Gal was at 11.4V so no wonder it was dead. Fitted another battery, showed 12.6V static, 11.8 with the engine running. Drove it home, NO alternator warning light on, although it came on and went off at start up as normal. Started to check the wiring and noticed the dash display now said "ALTERNATOR WORKSHOP". Traced the main wire from the alt' to a junction box type thing mounted up in front of the battery adjacent to the washer bottle neck. The top of this was melted slightly, inside there was a lot of charring and white oxide dust suggesting a long standing problem. Anyway the Alt' terminal was broken off so there was the problem. Made a new connection and it and measured 14.5V. Drove the 20 odd miles to work this morning and it was fine. I've ordered a new unit from Fraud Quote
Masked Marauder Posted January 21, 2005 Report Posted January 21, 2005 The most common cause of this type of damage is an insecure connection, that arcing out will burn away the terminals. 14.5v output is about right, your battery is 12.6v and it needs about 2v over maximum standing voltage to fully charge it. And my first reaction to the flat battery, no warning light, was that the bulb was blown. It is part of the charging circut, if it blows, the battery will not charge. Quote
GSMGuy Posted January 21, 2005 Report Posted January 21, 2005 Sorry m8, if the bulb blows it will have no effect on the charging of the battery. it is not in "the circuit" so to speak, as the power to illuminate the bulb comes from a seperate connection on the alternator. The bulb is purely to give an indication of a problem. Mike Quote
Andrew T Posted January 21, 2005 Author Report Posted January 21, 2005 Thanks Guys.The bulb comes on at start OK. I think the reason it didn't come on with the fault is that the Alternator was completely disconnected.A colleague who has a garage full of crusty old MGs and is therefore an expert on electrical failures (his words) has looked at it and come up with the same theory of a longstanding bad connection. Quote
johnb80 Posted January 21, 2005 Report Posted January 21, 2005 Sorry m8, if the bulb blows it will have no effect on the charging of the battery. it is not in "the circuit" so to speak, as the power to illuminate the bulb comes from a seperate connection on the alternator. The bulb is purely to give an indication of a problem. Mike Sorry, you're WRONG. The bulb is in the circuit to the alternator and provides the current to excite the windings to start the charging process, take the bulb out and try it, you'll find that the alternator won't charge. If anyone gets stuck with this situation, you can normally start the charging process by revving the engine to 4-5000 rpm, the residual magnetism is sufficient to start the charging process, once started it will continue until the next time the engine is stopped. Regards - John Quote
GSMGuy Posted January 21, 2005 Report Posted January 21, 2005 We'll agree to differ John, but a Dad who spent 20 years reconditioning at a Lucas main agent think you are wrong.... <_< Mike Quote
johnb80 Posted January 21, 2005 Report Posted January 21, 2005 Funny that because in the 70's I too used to spen my idle time reconning lucas alternators namely 17ACR, usually brushes but sometimes rectifiers and yes we can agree to differ but I do know this subject.The evidence from Andrew T also support what I KNOW to be true ! Within the alternator there is the STATOR and the ROTOR. The STATOR if fixed around the outside and carries the windings that generate the 3 phase power that is rectified into DC to charge the battery. The rotor also has windings, these are powered via slip rings from the control unit. The greater the voltage applied here, the greater the magnetic field and the higher the output voltage and hence current. The problem starts when you first start the engine, theoutput from the recitfier diodes goes straight to the battery, power is needed to kick start the charging process, the feed via the ignition light id fed to the control unit and then onto the slip rings of the rotor. This small current creates the small magnetic field to kick start the power generation. Once this has started the control unit feeds itself from the alternator and varies the voltage on the rotor as vehicle load and battery state require. The TIS CD also says "With the ignition on and the engine not running, voltage is supplied through the charging system warning indicator " However, when your bulb does blow, remember what I said and then help yourself to a slice of humble pie <_< TTFN - John Quote
Ivor_E_Tower Posted January 21, 2005 Report Posted January 21, 2005 Steady on, guys! No fighting now..... I hope that Ford aren't fitting Lucas alternators to the Galaxy. <_> Quote
Guest vr6galaxy Posted January 21, 2005 Report Posted January 21, 2005 Steady on, guys! No fighting now..... You'll know when it gets nasty Ivor, they start throwing MPG figures around <_< Quote
GSMGuy Posted January 21, 2005 Report Posted January 21, 2005 Ah the old 17 ACR brings back (rusty) memories of my old M2 RS2000 Escort <_< Mike Quote
johnb80 Posted January 21, 2005 Report Posted January 21, 2005 I bought my first ever sports car from repairing those things, a trusty old 'proper' Lotus 7 complete with twin webers and Ford BDA engine. That really was a fun car, no heater, no hood, no creature comforts but immense fun. Regards - JB (45-50 mpg <_< ) Quote
GSMGuy Posted January 21, 2005 Report Posted January 21, 2005 Ford BDA, now that was an engine - MUCH better than the lotus twin cam from the Cortina, and I believe, a distant forebearer of the Cosworth an RS200 lumps!! Mike <_< Quote
johnb80 Posted January 22, 2005 Report Posted January 22, 2005 It certainly was the start of the real engine developments, it's sound and power output unique in it's day. I do wish I'd mothballed that car, it would have been worth an absolute fortune today. Regards - John Quote
Andrew T Posted February 22, 2005 Author Report Posted February 22, 2005 I thought I'd solved this problem but I'm not sure now. I fitted the new distribution box (the invoice called it a fuse feed) with no problem and the car has run fine for the last month. Sunday night after a brief stop in the middle of a North Wales Forest it refused to restart, the dash lights went dim but the starter wouldn't turn. A quick push from Mrs T and it bump started straight away. Lucky because it was a very isolated spot and I wouldn't like to break down somewhere I couldn't even pronounce. Anyway it ran fine for the rest of the 2 hours home. Did a check and the Battery was at 12.6 V static 14.6 V running. I opened the new distribution box and found that the top was slightly stuck to the alternator cable again, suggesting things were getting warm again. I 've taken it to a trusted local garage who is going to replace the main alternator feed cable tommorow. Whist I can see this needs doing I can't see how it would prevent the engine from starting ? He's also suggested that the Alt' may have some sort of cut out to prevent overcharging which may have failed (and contributed to the failure of the original battery last Autumn?).Your thoughts ?. Quote
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