Camilla Posted November 20, 2012 Share Posted November 20, 2012 HelloIt turns out our dynamo had bitten the dust and the Herald is not charging so we have purchased a recon dynamo unit.I wanted to polerize it for our 1962 positive earth 1200 before firing it up.We’ve not done this before so just wanted to check if you all think the below instructions for polarising for POSITIVE earth are correct?http://www.dynamoregulatorconversions.com/polarising-a-dynamo.php if so, all sounds straight forward but what kind of wire should we use? Is 14 gauge insulated wire suitable?Thanks for your help.Cheers Camilla Quote Link to comment Share on other sites More sharing options...
herald948 Posted November 20, 2012 Share Posted November 20, 2012 Those instructions are fine, and I think 14 gauge wire will be fine as well. Quote Link to comment Share on other sites More sharing options...
Camilla Posted November 20, 2012 Author Share Posted November 20, 2012 just to check. you connect the positve earth to the frame, what about the negative? is this connected to the battery or disconnected?Also, where is a good highstreet place to get some suitable wire? sorry for the newbie questions.thanks Camilla Quote Link to comment Share on other sites More sharing options...
piman Posted November 21, 2012 Share Posted November 21, 2012 Hello Camilla, just to confirm your car is positive earth and you want to retain that polarity? Normally it is not necessary to polarise a replacement dynamo, it's a fit and go situation. However, with a positive earth system, the dynamo body is connected to the positive battery terminal via the engine block and earth strap to the body. You need to connect a wire to the negative battery terminal and touch the 'F' dynamo terminal (Smaller of the two dynamo terminals) with that wire. As I say, it should not be necessary to do that with a replacement dynamo.Alec Quote Link to comment Share on other sites More sharing options...
Camilla Posted November 21, 2012 Author Share Posted November 21, 2012 Yes our car is positive earth and we've just bought a reconditioned dynamo. I was told that its good practice to polerize it before installation? Is this not necessary then? Isn't there a chance the dynamo is negative and will then frazzle the voltage controller? Quote Link to comment Share on other sites More sharing options...
Keith Posted November 21, 2012 Share Posted November 21, 2012 Camilla,The dynamo relies on residual magnetism to first generate enough voltage to activate the field coils and get it going. If it's polarised the wrong way it will generate positive instead of negative volts could cause damage when the cutout contact closes nad connects it to the battery.One simple way of doing it if you don't have any bits of wire handy is to connect up the field contact (smaller one) to the dynmo but leave the armature (big one) off, then take the lid of the control box and manually close the cutout contact for a few seconds, The cutout contact is the one with the steel loop over it, as opposed to the regulatin contact which is the one with the adjusting screw.Keith Quote Link to comment Share on other sites More sharing options...
Camilla Posted November 21, 2012 Author Share Posted November 21, 2012 Hi Keith, that's great. Thanks for the advice. Just to make certain, do I connect both battery terminals when I do this? Everything else is crystal clear and I know which contact you mean in the regulator. Thanks again Camilla Quote Link to comment Share on other sites More sharing options...
Keith Posted November 21, 2012 Share Posted November 21, 2012 Yep, connect up the battery as normal.Keith Quote Link to comment Share on other sites More sharing options...
Camilla Posted November 21, 2012 Author Share Posted November 21, 2012 Amazing. I'm going to get stuck in now. Thanks for your help. Camilla Quote Link to comment Share on other sites More sharing options...
Camilla Posted November 21, 2012 Author Share Posted November 21, 2012 Ah! Nothing's ever simple. I've just spent 45minutes trying to remove the pully from the old dynamo! Is there an obviously clever method that I am oblivious to? Please help!😳Thanks Camilla Quote Link to comment Share on other sites More sharing options...
Keith Posted November 21, 2012 Share Posted November 21, 2012 Is the problem getting the nut undone?Wrapping an old fan belt around the pulley and clamping it in a vice is a good way of securing it while you undo it.Then undo the nut until it is flush with the end of the shaft to protect the threads and give it tap while holding the dynamo by the pulley.K Quote Link to comment Share on other sites More sharing options...
Camilla Posted November 21, 2012 Author Share Posted November 21, 2012 The nut came off with a little encouragement but the pully is completely stuck. Is it simply brute force that's needed? I'll lather it with wd40 over night and try again tomorrow in a vice if that's the case. I just wasn't sure if there was a technique or tool that was required. Quote Link to comment Share on other sites More sharing options...
herald948 Posted November 21, 2012 Share Posted November 21, 2012 Hopefully the WD-40 (or perhaps a more "dedicated" penetrating oil) will help. Thing is, you don't want to get too physical with the pulley, as it can be a bit fragile. Quote Link to comment Share on other sites More sharing options...
Camilla Posted November 21, 2012 Author Share Posted November 21, 2012 What's your suggestion of a more dedicated oil? I don't fancy spending another £50 on another pulley and fan! Quote Link to comment Share on other sites More sharing options...
Mark Hammond Posted November 21, 2012 Share Posted November 21, 2012 Loosen the nut and welt the end of the shaft with a hammer (using a drift). Works for me, anyway.M. Quote Link to comment Share on other sites More sharing options...
herald948 Posted November 22, 2012 Share Posted November 22, 2012 3648 wrote:What's your suggestion of a more dedicated oil? I don't fancy spending another £50 on another pulley and fan!Sorry, I should have elaborated! WD-40 isn't all that great as a penetrating oil. Here in the US we have Kroil, PB Blaster, Liquid Wrench and others, all of which claim (and most of which succeed fairly well) to loosen rusted parts! Quote Link to comment Share on other sites More sharing options...
SRF Posted November 22, 2012 Share Posted November 22, 2012 I don't want to go too far off topic, but for penetrating fluid a brand called Plus Gas is very good. Also I find Automatic transmission fluid or power steering fluid are excellent as well. Quote Link to comment Share on other sites More sharing options...
Camilla Posted November 24, 2012 Author Share Posted November 24, 2012 amazing! i only went and bloody did it! got the pulley and fan off in one piece and fitted the new dynamo. running like the proverbial dream. Is there a way to tell if it has been correctly polarised? i did as Keith instructed and its all working. just wondering if i've done it correctly as i'd rather it didnt melt our voltage regulator. Thanks Camilla Quote Link to comment Share on other sites More sharing options...
junkuser Posted November 24, 2012 Share Posted November 24, 2012 Good for you Camilla.You will not have done any damage and if the "ignition warning " lamp is off, it is charging.If the lamp stays off with the lights turned on it is probably charging enough.If the ammeter is is the positive side with lights on, the level of charge is adequate. Quote Link to comment Share on other sites More sharing options...
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