Am I the only person who's noticed the enormous amounts of heat coming up
from the equipment on the 2009 stock when stopped? I presume its the motors or
the brakes but I guess it could be the traction controller too. This heat then
get sucked into the cars by the ventilation fans just above which isn't very
pleasent if you're inside at the time.

Arn't these trains supposed to be more efficient than their predecessors?
I never noticed the 67 stock pouring out heat like this.

B2003

In article , d ()
wrote:

*From:* d
*Date:* Thu, 5 May 2011 08:55:38 +0000 (UTC)

Am I the only person who's noticed the enormous amounts of heat
coming up
from the equipment on the 2009 stock when stopped? I presume its
the motors or the brakes but I guess it could be the traction
controller too. This heat then get sucked into the cars by the
ventilation fans just above which isn't very pleasent if you're
inside at the time.

Arn't these trains supposed to be more efficient than their
predecessors?
I never noticed the 67 stock pouring out heat like this.

B2003


I haven't seen a 2009 stock, but most of the heat on a train comes from
the motors (they use several hundred amps of electricity, which ends up as
heat). Newer stock also generate heat from the equipment controlling the
traction equipment. There is also a lot of heat generated when braking as
the regen brake feeds current to resistors and, of course, this then ends
up as heat as well.

This heat is easily felt rising up when standing near the platform / edge
motor car after the train has stopped. Because the newer trains with fan
circulated air (such as 95 stock etc.) sometimes take their "fresh" air
from outside (rather than recycling used air from inside), this can cause
problems in tunnel sections as the cooling fans almost act like fan
heaters!

Roger

wrote in message

There is also a lot of heat
generated when braking as the regen brake feeds current to resistors
and, of course, this then ends up as heat as well.

Surely regenerative braking is the one thing that does *not* generate
heat, as the reclaimed power is fed back into the traction supply?

In article ,
(Recliner) wrote:

*From:* "Recliner"
*Date:* Thu, 5 May 2011 11:10:36 +0100

wrote in message

There is also a lot of heat
generated when braking as the regen brake feeds current to
resistors
and, of course, this then ends up as heat as well.

Surely regenerative braking is the one thing that does *not*
generate heat, as the reclaimed power is fed back into the traction
supply?



Sorry, my mistake, you're right. I meant to say Rheo brake. Although the
newer stock are capable of regen braking, I don't know if it is actually
used. I can't recall it ever being in use on the 95 stock. Also, even if
it is switched on, without checking the details, I'm certain the train
will only use the regen brake if there is a demand elsewhere in the
section for the current it's supplying.

Roger

In article ,
(Recliner) wrote:

wrote in message

There is also a lot of heat generated when braking as the regen brake
feeds current to resistors and, of course, this then ends up as
heat as well.

Surely regenerative braking is the one thing that does *not*
generate heat, as the reclaimed power is fed back into the traction
supply?

Indeed so. But the fallback is rheostatic braking if the line is not
receptive to the regenerated energy.

--
Colin Rosenstiel