South Downs Railway

Modern Image, Computer Controlled

Author login

Phoca Gallery Tree Module

Warning: "continue" targeting switch is equivalent to "break". Did you mean to use "continue 2"? in /homepages/45/d549400858/htdocs/nicklebyhousewebsite/templates/sdr_template_nov17/functions.php on line 199

Power Generation & Control

Balancing PM42 zones

All the PM42 zones were programmed to trip at 3A current load. So why were some zones tripping when any train ran, while others did not?

That kind of problem demanded a scientific investigation. What I did was to purchase a set of 47Ω power resistors (rated at I think 3W each). Each of these added across the rails would add a 0.25A load, approximately; with some accurate voltage measurements and a spreadsheet I would know the truth. As it turns out, my multimeter when set to "AC Volts" gave a near exact voltage reading: I calibrated it against true peak-peak rail voltage using an oscilloscope.

The results, when I got them, were surprising: two of my PM42 modules had current trips close to the "brochure" figures; the other two - at the fiddle yard end- had trip points significantly lower than the others. I'd bought them at different times; I don't know if there has been a design change. However armed with these measurements I was able to balance the current limits by reprogramming the over-sensitive PM42 modules. 

VCNT - Visitorcounter

Today 8

Yesterday 44

Week 209

Month 260

All 48904

Currently are 12 guests and no members online

Kubik-Rubik Joomla! Extensions

Using this Site


The web site can be searched: type a search term (e.g. "DAC10") into the search box on the right hand side of the header, and hit enter. the search engine will find words matching the search string in the main body of the site, but it won't search attached documents (e.g. the product manuals).

"Read More"

Many articles are displayed one after the other. some are quite short, and say "read more" at the bottom. Click that to read the remainder of the article.

Gaugemaster News

Feed not found.