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| Mini Lathe Electrikery....... |
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| doubletop:
To add my tupence to this I'd say the filter board arching is a symptom and not the cause of the problem. It certainly isn't going to make the motor go backwards at full speed. If a track is burnt through nothing will run, if C1 or C2 (the one on the live side) is shorted the mains fuse will go and then nothing will run. If C1 or C2 have failed open you'll only get noise on your TV. If its the brushes then maybe its a back EMF that caused the spark on the filter board and has also progressively trashed the speed controller eventually leading to a catastrophic failure causing the motor to run backwards for a while and then it got totaled. Look for similar arching on the speed controller, evidence of arching on the brushes and commutator. If you find problems fix them all otherwise you'll be back here. Apologies if I've repeated what has been said before but my money is on the filter being a red herring. Pete |
| John Rudd:
--- Quote from: andyf on May 17, 2011, 07:07:56 PM --- I have the circuit schematics and parts list which KB have now unsportingly removed from the manual, so if you need them, give me a shout. Andy --- End quote --- I have the parts list and circuit archived if anyone else needs them, give me a shout......... Dont by pass the board, connecting the motor direct to the mains!!! it is a dc motor with a permanent magnet field....Quite different to a drill motor... |
| lordedmond:
John its not the controller board is just a mains filter to filter out the odd order harmonics generated by the switching pulse width controller , the controller board is bigger and has mosfets on it the board in question ha only passive parts on it a couple od c's and a choke note the colour of the cables and number of them,, live ,neutral and earth no othe connections for speed pot emergency stop etc Stuart |
| Stilldrillin:
Well.... I fitted 3a fuse in plug. (I've got plenty)! Couldn't find me 60watt test lamp. So, I just wired it together with junction block, and no blackened gubbins...... I switched on. Released emergency switch lock. Selected forward (probably). The motor spun up for 1 second. POP! :zap: Plug fuse blown...... Hadn't seen a flash. So, I repeated with lights out. POP! :zap: Flashed inside the motor. So, I went out for a walk........ :thumbup: David D |
| Bluechip:
Dave SD If you can get it to me tomorrow, I'll have a look. I have a Variac + Bridge rectifier so we can verify the motor itself. Got dozens of fuses, so that's no problem. Can you give a pic of the controller board, I have some S8020L SCR's from when mine did the 'phttts' on me. I think :scratch: If it's the one with SCR's .. EDIT ................. YES, I HAVE 4 of the little blighters :thumbup: Anyone know what MOSFETS are in t'other sort. Got loads of them too, just no idea what they are. It may be I have a suitable substitute. Dave BC |
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