222's

[222007]

Hi all

i've been wondering for some time now about this so hopefully someone more knowledgeable will know the answer. I believe its when they brake there's a whirling sound in the saloon what is this? Sorry if ive not discribed it very well.

 

[Yew]

Its the rheostatic braking. They use the motors to put a load on the wheels to slow the train down, this generates electricity which then is put through resistors in the bodyshell of the train. This electricity causes some interferance with the PA system, Hence the noise

 

[222007]

Much appreciated. I've used them a fair amount and always wondered that answers my question

 

[Alan1310]

As far as I am aware the resistor bank is on the roof near the vestibules as I say as far as I know so I am prob wrong

 

[ainsworth74]

As far as I am aware the resistor bank is on the roof near the vestibules as I say as far as I know so I am prob wrong

This is correct. The resistor bank is the large black object about two-thirds of the way along the carriage in this photo:

 

[westcoaster]

This is correct. The resistor bank is the large black object about two-thirds of the way along the carriage in this photo:

I believe this is also where the heat disapates from , hence why when you look there is always a heat haze coming from the roof.

 

[IanXC]

I believe this is also where the heat disapates from , hence why when you look there is always a heat haze coming from the roof.

Not exactly "also", the purpose of the resistor banks is to turn the electricity produced as Yew describes into heat. I don't think there is any other mechanism to release heat through them.

 

[ainsworth74]

Not exactly "also", the purpose of the resistor banks is to turn the electricity produced as Yew describes into heat.

Which is a complete waste of all that energy (unless anyone likes char-grilled pigeon ). I wonder, assuming that Bi-modeification goes ahead, if there will be any thought of fitting regenerative breaking to the 220s to let them put some of that energy back unto the OHLE?

 

[CC 72100]

Its the rheostatic braking. They use the motors to put a load on the wheels to slow the train down, this generates electricity which then is put through resistors in the bodyshell of the train. This electricity causes some interferance with the PA system, Hence the noise

Is this the same for 220s and 221s? Again when breaking there seems to be this sound in the bit of the passenger saloon close to the vestibule doors.

 

[jopsuk]

You would have to hope so. But it is energy that would be wasted using any other sort of brake, be it the hydro brake on the 180s, disk brakes or tread brakes. The rheostatic brakes have little/no wear; there are no "pads" that need replaced (as in disk/tread) and the wheels do not get worn (as in tread).
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Is this the same for 220s and 221s? Again when breaking there seems to be this sound in the bit of the passenger saloon close to the vestibule doors.

Yes- the example picture shown is of a Voyager (it is the same layout for a 222)

 

[CC 72100]

Yes- the example picture shown is of a Voyager (it is the same layout for a 222)

Thought as much, looking on the picture again of course it's a voyager!