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6 comments
Anonymous Poster #1

Railway Transportation System

08/08/2017 9:04 AM

Hi,

These days electrical railways are becoming popular. Why are bi-directional rectifiers used in electrical railways?

Regards

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Anonymous Poster #2
#1

Re: Railway Transportation System.

08/08/2017 9:09 AM
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Anonymous Poster #2
#2

Re: Railway Transportation System.

08/08/2017 9:23 AM
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#3

Re: Railway Transportation System

08/08/2017 12:24 PM

Bi-directional rectifiers are used so the trains can run in both directions, silly.

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#5
In reply to #3

Re: Railway Transportation System

08/08/2017 10:30 PM

What the heck is a Bi-directional rectifiers? I thought they were all one-way check-valves.

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#4

Re: Railway Transportation System

08/08/2017 7:32 PM

Because if they used uni-directional rectifiers, they would get stuck!

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#6

Re: Railway Transportation System

08/10/2017 7:06 AM

"These days" ELECTRIC VEHICLES (electric cars as well as raiways) use bidirectional converters to allow regenerative braking.

For battery powered vehicles the excess energy goes to the battery.

For trains the energy goes trough the overhead line either to other trains that require the energy, or to the static converter that has to hold the voltage within specifications.

Easy right? Well, not really.

Regenerative braking has its limits. For battery powered vehicles, the battery cannot be overcharged (free energy BS?). However, in "cheap" static converters where the energy goes to resistors, the limit for braking is usually the maximum speed a train should go at.

Being in a hurry and driving a train too fast can be more DANGEROUS than doing the same with battery powered vehicles.

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