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Post by ikar on Oct 27, 2005 10:50:07 GMT
What does Series and Parallel mean on the handle.
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Post by piccadillypilot on Oct 27, 2005 12:43:03 GMT
What does Series and Parallel mean on the handle. To put it simply:- When the Master Controller is at Series the Traction Current is passing through each motor therefore the 630 volts is divided amongst them. In Parallel each motor is getting the full 630 volts and so will go faster. |
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Post by Christopher J on Oct 27, 2005 12:58:14 GMT
Ikar - go 3/4 of the way down the webpage below to 'Series-Parallel Control' www.railway-technical.com/tract-01.htmlI hope it may be of some help. Edit - just noticed PP's post... PP's answer is a simple as it can get! |
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Post by Deleted on Oct 27, 2005 18:14:25 GMT
Ha! Love the sound of the 'changeover' when Op's start away from stations in Series, and then go into Parallel. Also, when I'm about on the Met, for some bizarre reason, I like sitting near the PCM. Pull away from station with that tik-tik-tik-tik-tik noise as the PCM notches up, TACK! when power is shut off, and tik-tik-tik-tik-tik again as power is re-applied. Call me strange why don't you!!!
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Post by Deleted on Oct 27, 2005 18:20:45 GMT
Call me strange why don't you!!! Strange! ;D (Sorry, do I win the award for the most predictable reply of the week?!) |
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Post by Deleted on Oct 27, 2005 18:34:42 GMT
Call me strange why don't you!!! Strange! ;D (Sorry, do I win the award for the most predictable reply of the week?!) ;D ;D ;D ;D ;D |
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Post by Deleted on Oct 27, 2005 20:28:13 GMT
Ha! Love the sound of the 'changeover' when Op's start away from stations in Series, and then go into Parallel. Also, when I'm about on the Met, for some bizarre reason, I like sitting near the PCM. Pull away from station with that tik-tik-tik-tik-tik noise as the PCM notches up, TACK! when power is shut off, and tik-tik-tik-tik-tik again as power is re-applied. Call me strange why don't you!!! Hey, I like the sound of the PCM on the older stock. Oh, and the MA whine and do even get me started on compressors ;D |
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Post by Christopher J on Oct 27, 2005 20:33:12 GMT
'cuss ones lack of knowledge but what is a PCM? I believe that 'notching' sound comes from the RPA (Rotary Pneumatic Accelerator) which allows the 600V into the motors progressively by 9 notches using Main Line air, never heard of a PCM before.  |
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Post by Deleted on Oct 27, 2005 20:37:09 GMT
[quote author=david5032 board=Trains thread=1130410207 post=1130444893 Hey, I like the sound of the PCM on the older stock. Oh, and the MA whine and do even get me started on compressors ;D[/quote] ------------------------------------------------------------------------ You got me going now!!! I will never forget the noises 59's and 62's used to make. Only memories now, but at least the A60's make similar sounds. A good friend has some recordings of all things LUL and has been meaning to do a copy for me for some, err, TWO years. I'm still waiting...paitently...  Pm on its way David5032...  |
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Post by Deleted on Oct 27, 2005 20:40:03 GMT
'cuss ones lack of knowledge but what is a PCM? I believe that 'notching' sound comes from the RPA (Rotator Pneumatic Accelerator) which allows the 600V into the motors progressively by 9 notches using Main Line air, never heard of a PCM before. PCM - Pneumatic Camshaft Mechanism - used on the 38ts - I guess PCM is similar to the RPA |
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towerman
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Post by towerman on Oct 27, 2005 22:22:41 GMT
RPA/PCM same thing just some folks call it one thing and some the other.
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Post by zman on Oct 28, 2005 1:53:58 GMT
In layman's terms:
Series will make the train, on level ground, go about 18-20 mph.
Parallel will make the train go as fast as it can.
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Post by Deleted on Oct 28, 2005 7:55:39 GMT
also it seems that in BVE (i dunno how accurate this is) that series can hold a train's speed quite well providing your doing 30 - 40mph
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Post by q8 on Oct 28, 2005 10:46:56 GMT
Oh memories of WCTC agian. They used to teach us the contacts making in first point. 'M1' JR' & '10' for RPA (which is Rapid pneumatic accelerator by the way) and PCM. For older stock it was 'S1' and '7'
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Post by Deleted on Oct 28, 2005 14:31:26 GMT
RPA (which is Rapid pneumatic accelerator by the way) Sorry Bob, it's definitely ROTARY Pneumatic Accelerator. At least it is these days! |
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Post by q8 on Oct 28, 2005 15:47:34 GMT
RPA (which is Rapid pneumatic accelerator by the way) Sorry Bob, it's definitely ROTARY Pneumatic Accelerator. At least it is these days! ----------------------------------------------------------------------- Well I still have stock notes for 'R' stock when introduced. and in print it is 'Rapid'. So 'these days' has it wrong!!  Strange thing though is that whilst it was 'RPA' on 'R' stock it was 'PCM' on 'COP' an '38's yet it's the same thing.  |
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towerman
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Post by towerman on Oct 28, 2005 19:36:18 GMT
When I started in '66 it was rotary.
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Post by Deleted on Oct 29, 2005 20:46:58 GMT
With regards to PCM camshafts, can anyone explain why drivers have always been taught to notch up into shunt when starting from rest and then whack around into parallel?
Some drivers say they do it when near rail gaps to avoid the crash as the line breakers open and the camshaft 'winds back', whereas others say that some stock doesn't like to notch up to parallel from rest and will sometimes throw a wobbly. What do the learned individuals of the forum have to say?
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towerman
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Post by towerman on Oct 29, 2005 21:05:45 GMT
It's generally to stop wheelspin,also 72Mk1's had a tendency to lose the pilot light if you accelerated to quickly.
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Post by Colin on Oct 31, 2005 2:19:24 GMT
also it seems that in BVE (i dunno how accurate this is) that series can hold a train's speed quite well providing your doing 30 - 40mph BVE is only a simulator - don't forget that!! On the real thing, with gradient, speed, etc taken into account - series will generally hold the speed in the 20 - 30 mph bracket. With regards to PCM camshafts, can anyone explain why drivers have always been taught to notch up into shunt when starting from rest and then whack around into parallel? Some drivers say they do it when near rail gaps to avoid the crash as the line breakers open and the camshaft 'winds back', whereas others say that some stock doesn't like to notch up to parallel from rest and will sometimes throw a wobbly. What do the learned individuals of the forum have to say? Shunt? I was taught to start in series for a few seconds, then onto parallel. To be honest, I can't remember the exact reason - except that i'm sure the line breakers had something to with it. Note to self: check up before Solidbond does my stock refresher. |
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Post by Deleted on Nov 1, 2005 1:17:37 GMT
RPA (which is Rapid pneumatic accelerator by the way) Sorry Bob, it's definitely ROTARY Pneumatic Accelerator. At least it is these days! Well sorry Alan, because Bob is dead right!! RAPID Pneumatic Accelerator is what we were taught at the White City Training Centre. And we're both older than you, so 'ner'!! ;D |
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Post by Deleted on Nov 1, 2005 1:50:45 GMT
Here's another bit of uninteresting information for you. 'PCM' originally stood for 'Pneumatic Camshaft Modified', refering to the addition of oil to damp the operation of the switchgear in the early days. But, to quote from one of J. Graeme Bruce's excellent books on LT rolling stock "PCM has since been taken to mean Pneumatic Camshaft Motor".
So there you go, with RPA and PCM meaning basically the same thing. I have a feeling that 'RPA' referred to the original traction control equipment fitted to 'Q' stock and 'standard' tube stock, with 'PCM' being fitted to everything built from 1938 onwards (well until 1983 anyway), but ready to be shot down in flames if I'm wrong on that! ;D
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Post by Deleted on Nov 1, 2005 4:12:42 GMT
Well sorry Alan, because Bob is dead right!! RAPID Pneumatic Accelerator is what we were taught at the White City Training Centre. fair enough! It's obviously another of these names which has changed over the years! I'll certainly not argue with that statement! ;D |
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Post by q8 on Nov 1, 2005 5:54:20 GMT
Nah. The notch controll on standard and 'Q' stock was called the 'accelerating relay' and was in the cabs. Common name was 'Dancing Dollies'.. RPA was first used for the 'R' stock.
To answer TOK's querie. You were told 'First point and hold' This was to ensure that reversers were properly thrown and that the breakers had latched fully.
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Post by q8 on Nov 1, 2005 9:50:05 GMT
I will tell you how the term 'RPA' Came about. LT often fitted a normal train with a bit of non-standard kit for experimental purposes. Trains so fitted ran in normal service. One of the experiments was to 'R' stock car 21148. This was an AIR/AIR camshaft mechanism. This was made by G.E.C. I think. It had individual air cylinders for each step of the notching process. There was no oil in the thing other than lubrication. It did not 'tick' like a normal camshaft but 'hissed' as each notch was reached. TTsss..t, ttsss..t would be the closest you could get to describing it. It was much better than normal PCM in that as the motors on that car were G.E.C also it had some guts in it and you could actually feel the power through the seat of your pants. 21148/49/50 were always the fastest of the 'R' stock as they all were converted in 1959 and had G.E.C motors from the off.
I know I am late posting this but I looked through my notes and remembered where the term RPA came from. Prior to 1959 it was always PCM
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Post by Deleted on Nov 1, 2005 14:58:02 GMT
Shunt? I was taught to start in series for a few seconds, then onto parallel. To be honest, I can't remember the exact reason - except that i'm sure the line breakers had something to with it. Yes, Dave said the exact same thing to me. You go to Off and Release for a few moments, (to aboid motoring with the brakes on) and then onto series, after a while into parallel. Dont ask me why, but it does give a smooth 'take off' from stations! |
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Post by Deleted on Nov 1, 2005 19:58:17 GMT
Looks like my message about PCM noises has prompted a rather lively debate!!! ;D ;D ;D
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Post by Deleted on Nov 2, 2005 1:06:28 GMT
Looks like my message about PCM noises has prompted a rather lively debate!!! ;D ;D ;D Indeed!!! Ker-lunk (linebreakers closing), tick, tick, tick, tick, tick, tick, tick, tick, tick, hiss & click (switching from series to parallel), tick, tick, tick, tick, tick, tick, tick, tick, tick, latching click (bringing in weak-field if flag-switch is up). Job done. But did you know (my eldest son and I do this 'did you know' stuff when we've had a few beers!) that the run-up of PCM equipment can held in mid-step, at any 'tick', by moving the handle back to Shunt (or Inch on very old stock) to control the rate of acceleration. Wonder if that works the same on BVE(?!) |
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Post by piccadillypilot on Nov 2, 2005 7:50:21 GMT
that the run-up of PCM equipment can held in mid-step, at any 'tick', by moving the handle back to Shunt (or Inch on very old stock) to control the rate of acceleration. Otherwise known as "hand-notching". Sadly we were never taught it officially, it's one of those things you learn from more experienced people. It's useful when passing over current rail gaps that are just in advance of a platform. If you wind up to series, then touch parallel and straight back to shunt and then back to series. You get good acceleration but not the huge lurch as the motors on each car drop out. |
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towerman
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Post by towerman on Nov 2, 2005 20:35:33 GMT
Hand notching is the approved way to overcome the SAPB if you have a burst.
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