<html><body>Hi Michael-seems like you are describing overdrive relays (the ones shown in the upper left in this pic) The early cars using two relays w/governor and the later single relay. All use the W and C connections in the schematic.<div><br></div><div>The thing with Lucas is that they kept changing the inventory part number (same item) to a 5, 6, 7 and 8 digit numbers to avoid inventory tax. They eventually got caught and that helped to put them out of business. All those different numbered boxes can do the same job. I have those Lucas numbers if you need them. Regards, Hank<br><br><div class="reply-new-signature"></div><p>-----------------------------------------</p>From: "Michael Salter" <michaelsalter@gmail.com><br>To: healeys@autox.team.net<br>Cc: <br>Sent: Tuesday January 28 2020 2:19:27PM<br>Subject: [Healeys] Lucas 6RA Relays<br><br>
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One for the electrical geniuses.
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As I sort my way through my boxes and boxes of electrical parts I keep coming across Lucas 6RA relays. These are the ones in the little steel box with the bracket on the back with 2 mounting holes.
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Ignoring those with more than 4 terminals I must have at least 15 different Lucas part numbers for what appears to be the same relay.
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All are 12 volt and all have 4 terminals
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W1 & W2 which are the coil (winding) and C1 & C2 which are the contacts ... like what get switched.
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A couple are normally closed contracts (NC) but the vast majority are normally open (NO).
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I have checked the continuity between the various terminals and in all cases the C terminals are isolated from the W terminals and all terminals are isolated from the steel enclosure.
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I've opened a few up and, internally, as far as I can tell, they appear to be virtually identical.
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So ... to my question ... why all the different part numbers, as I understand it these things are essentially an electrically operated switch, what can be so different between them that they need to have so many different part numbers?
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Perhaps I should also mention that Lucas is very particular in requiring a specific part number for each application... what am I missing.
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Please avoid comments referring to the long Canadian winter ... they make my wife angry ... she's a local and they get a bit sensitive when such is mentioned 😊
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M
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