traction current bleed resistors

neilw

now that's what I call a garden railway

Posts: 284

traction current bleed resistors May 5, 2018 11:53:45 GMT

Post by neilw on May 5, 2018 11:53:45 GMT

Hi there

Has anyone got any information and/or photos about the traction current bleed resistors at the end of the traction current sections, please? We're in need of something for the Tramway Museum so any information would be helpful, thanks. Info such as current rating, resistance value, and potential suppliers (sorry for the pun....)

many thanks

goldenarrow Global Moderator Posts: 1,887	traction current bleed resistors May 5, 2018 19:37:32 GMT Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by goldenarrow on May 5, 2018 19:37:32 GMT I think resistance stood at 220 ohms on the negative rail and 110 ohms for the positive rail. This was in the early 2000's, I'm unsure if the 750V upgrade on the SSR has changed this though.
	Last Edit: May 5, 2018 19:41:43 GMT by goldenarrow Child of Middlesex, student of the City, resident of the Metropolitan

roythebus Pleased to say the restoration of BEA coach MLL738 is as complete as it can be, now restoring MLL721 Posts: 1,275	traction current bleed resistors May 7, 2018 8:18:36 GMT Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by roythebus on May 7, 2018 8:18:36 GMT As a matter of interest, what do they do?
	Keeping Europe's Routemasters on the road.

bananaman

Posts: 39

traction current bleed resistors May 7, 2018 8:32:41 GMT via Tapatalk Chris M likes this

Post by bananaman on May 7, 2018 8:32:41 GMT

May 7, 2018 8:18:36 GMT roythebus said:

As a matter of interest, what do they do?

They provide an Earth reference, which is how we end up with a +420v rail (the posi) and a -210v rail (the negi). This known earth reference makes it easier to detect unwanted earths, i.e. a short between a con rail and a running rail.

bananaman Posts: 39	traction current bleed resistors May 7, 2018 8:38:40 GMT via Tapatalk Dstock7080 and piccboy like this Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by bananaman on May 7, 2018 8:38:40 GMT Or +500v and -250v to my SSR colleagues....

neilw now that's what I call a garden railway Posts: 284	traction current bleed resistors May 14, 2018 9:38:05 GMT Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by neilw on May 14, 2018 9:38:05 GMT many thanks goldenarrow

Post by neilw on May 5, 2018 11:53:45 GMT

Post by goldenarrow on May 5, 2018 19:37:32 GMT

Post by roythebus on May 7, 2018 8:18:36 GMT

Post by bananaman on May 7, 2018 8:32:41 GMT

Post by bananaman on May 7, 2018 8:38:40 GMT

Post by neilw on May 14, 2018 9:38:05 GMT