Door Closing chimes on EMR Intercity services

[Bletchleyite]

Potentially when switched away from neutral the traction electronics are switched-in and there's a 'parasitic' draw on these?

The other thing to bear in mind though is that more rpm doesn't necessarily mean more power (it does if torque stays constant, but at idle that's not necessarily a given) - a diesel engine > alternator > traction electronics system has a lot of variables at each stage that doesn't just mean that a faster engine speed is bringing more power out of the generator. It may well just be the case that the engines are run slightly faster so that there's a quicker response once power is actually demanded (turbos a bit more spooled, etc) - but given how quickly the engines rev up from the lower idle speed to the fast idle, I'm not so sure. Or maybe traction electronics that need a higher input frequency than the auxiliary systems do

Thanks. The turbo thing does make a bit of sense - I know my car "likes" being in a lower gear if the road is undulating, as otherwise you get a very jerky drive as you get to a hill with the turbo spun down and it takes a second or so for it to spin back up and give you power to climb it. Also happens when the aircon compressor kicks in.

 

[Domh245]

Thanks. The turbo thing does make a bit of sense - I know my car "likes" being in a lower gear if the road is undulating, as otherwise you get a very jerky drive as you get to a hill with the turbo spun down and it takes a second or so for it to spin back up and give you power to climb it. Also happens when the aircon compressor kicks in.

It's speculative on my side - I'd love to know the real answer as well if anybody can confirm it! I was thinking about the tales you've told of your car and it's turbo whilst writing it out!!

 

[Hairy Bear]

Why do 22x engines rev up as the doors are closing? Long wondered that.

It's to increase the alternator excitation prior to taking power for traction.
The door hustle alarm is normally inaudible from the outside with engines running. That's why so many get walloped by the doors closing because they can't here it. Great design!

 

[Bletchleyite]

It's to increase the alternator excitation prior to taking power for traction.

Cheers!

The door hustle alarm is normally inaudible from the outside with engines running. That's why so many get walloped by the doors closing because they can't here it. Great design!

22x were certainly a decent "first go" at an underfloor 125mph InterCity DEMU, but do have many lessons to learn.

On Voyagers I suppose you at least hear the "10 bell" which is louder than the hustle alarm.