On approach to a neutral section...

[Edvid]

...which AC EMUs have the loudest circuit breakers?

In my experience the CBs in Class 357s are rather loud - perhaps even loud enough to wake anyone who isn't in a coma or deep slumber. If you're seated/standing anywhere within the pantograph coach then you can hear the equipment in action - compare that to (for argument's sake) a Class 319 where you have to be more or less under the pantograph to hear the circuit breaker.

 

[Juniper Driver]

Don't know about the 357's but I remember the 302,305s + 307's took a bit of getting used to although that was 20+ years ago when I was a guard.

 

[Chilled Phill]

323s have a noticeable sound. But, tbh, I tend to notice the dead silence and the slightly dimmer lights over the sound most of the time.

 

[O L Leigh]

Generally all VCB's are the same design so should all be as loud as each other. There may be issues with how the VCB is mounted to the roof and how thick the roof is which may result in more noise being transmitted, but they should all work and sound the same.

There may be other switches that operates with the VCB on newer 3-phase units like Cl357's to protect certain systems from a "hard start" when the VCB cuts back in that cause the noise you can hear. It's certainly the case that a Cl360 "Doodlebug" doesn't spring straight back into life the moment the VCB slams shut again. Annoyingly for the driver, you have to coast for a certain amount of time before the unit comes back to you and you can take power again because all the onboard systems that run directly from the transformer need to go through a restart procedure.

That said, it may simply be that certain individual VCB's are louder than others. I've certainly noticed this when travelling under the pan in Cl317's. Some are almost completely silent while others switch with a resounding "clang".

O L Leigh

 

[Danielo]

You can hear a bit of a thump in a 350.

 

[33056]

You can hear a bit of a thump in a 350.

Even more so on a 377, nearly had to peel someone off the ceiling after going through Headstone Lane a few months ago

 

[GNERman]

333's are rubbish...

 

[90019]

333's are rubbish...

As in loud or quiet?

 

[delt1c]

Been using C2C quite a lot last week and have to say the 357's are loud sitting below the Pantogragh, doesnt have make you jump

 

[metrocammel]

Pendo's have quite a noticeable 'thump' when you sit underneath the pantograph.

 

[Shinkensgone]

That said, it may simply be that certain individual VCB's are louder than others. I've certainly noticed this when travelling under the pan in Cl317's. Some are almost completely silent while others switch with a resounding "clang".

O L Leigh

Reminder V stands for vacuum ergo no sound from a VCB

 

[shinkansen09]

Pendo's have quite a noticeable 'thump' when you sit underneath the pantograph.

A real "thump" comes from an "Air Blast Breaker" these were the forerunner to VCB`s and worked on a small valve being located next to the high voltage contact which when opened allowed high air pressure to blow out any arc that may have been created when the contact opened. On an SNCF class 1400 "Crocodile" ( had a centre cab) this was mounted on the driving cab roof and operated with Main Res pressure....140 psi or 10 BAR with no damping or souind isolation :roll:....it was impossible to sleep on one of these
Ken is right about Vaccuum and sound not travelling.....which is probably caused by the contacts at each end outside the main cylinder
Danielo
A 350 always goes clunk , has no VCB and is a class 08

 

[O L Leigh]

Reminder V stands for vacuum ergo no sound from a VCB

Wrong.

Sound is generated by an object vibrating and passing on those vibrations as sound waves through some medium separating the object from the hearer's ear (e.g. air, water or anything else). Assuming the vibrating object is floating free in a vacuum there is indeed no medium that can carry the sound waves.

However, in the case of a VCB, the internal mechanism is not floating free in a vacuum. The internal mechanism is attached to the outer casing which is more than sufficient to carry sound waves.

O L Leigh

 

[ungreat]

Lincolnometer..please change it from "Licolnometer" to "Lincolnometer"

How Licoln are you...dont wanna lick Coln,whoever he is lol!

 

[robby p]

It's mad how when i didn't know what a vcb was i didn't even notice a noise, you've got to admit they can't be that loud because you usually have to listen out for it when you know your passing a neutral section, 360s have extremely loud pop though!

 

[AC/DC Boy.]

Class 360's do have a noticeable noise, not as bad as the 321's which do have a very noitceable "clunk", noticeable the most as you enter Shenfield heading towards London.

 

[captainbigun]

There are three types of VCB, two are air operated, the other electrically operated. The twin bottle design which looks like a T on the roof which two ceramic insulators. This is a GEC design. EMU Classes 313-322 are so fitted, loco classes 89/90/91 are also fitted as have been a handful of Class 87s. The two bottles pull the contacts apart.

The newer design has a single bottle and is vertically mounted, EMUs 323 onwards are fitted with this design though there are several different manafacturers. 87009 is fitted with a prototype for the design used on the Pendolino. If you look at some of the photos from Long Marston you'll be able to see this.

The third design is an oddity made by Tyco and is fitted to 86424 which is stored at LNWR. This design never obtained approval for use on NR infrastructure.

The loudest breaker is the ABB as fitted to early units (312 and before) and loco classes 81-87. These are very loud, especially when stood on a roof next to one or stood directly beneath.

It's normal for the loco/units traction kit to await the VCB to close and then 'see' line volts before closing the motor contactors and power to be obtained....hence the post neutral section delay. Tap changer locos have to be run all the way to zero before power can be taken again after the breaker has closed. At speed on a gradient than equates to quite a large drop in speed 10-15 mph in some cases. Phase angle (such as 321s/90s) or inverter drive (357s/360s) traction can ramp the power application up (and down) much quicker hence there's less speed lost.

 

[Trainee]

I guess you need a VCB on all AC & Dual voltage trains?

I thought that GEC made the twin bottle VCBs, in the Trafford Park Manchester factory, & sold them all over the world. That factory closed years ago, I wonder what happened to that design? Did Alstom make & continue to supply the twin bottle from the plant in Preston?

What about the single bottle VCB, you say there are several manufacturers - I wonder how many of these are British? Do Bombardier,Alstom, Siemens & Hitachi have the own design, is there some sort of Joint venture and a common part for the UK fleet?

Do we make any switchgear for trains in the UK anymore?

 

[Juniper Driver]

The loudest breaker is the ABB as fitted to early units (312 and before) and loco classes 81-87. These are very loud, especially when stood on a roof next to one or stood directly beneath.

Yeah in the 305's it banged in the guards brake....and other units.Can't remember much now as it was nearly 25 years ago.