hst speed controller

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AndrewE

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The driver controls the speed by varying the engine power. Don't know if any UK rolling stock has speed control other than Slow Speed Control (SSC) which was fitted for unloading at merry-go-round power stations. It makes it very difficult to move a train dead slow when you want to unload ballast or something similar.

Mind you it would have been very helpful for driving passenger stock through carriage washing machines, where precise control of speed is critical.
 
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dgl

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I'm pretty sure modern bombardier EMU's have 'speed set' which is similar to cruise control as on automobiles and I suppose other stock have the same.
 

gimmea50anyday

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The cl185 has a speed set function. Once set jjst like a cruise control one of the engines drops and shuts down leaving 5hw remaining 2 to maintain the speed
 

ash39

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Think the wrong question is being answered here. The OP asked about engine speed, not actual speed.

Yes, each notch gives a particular engine speed. I think there are 5 notches on a HST, the RPM at each notch depends on the engine fitted and how it's set up. www.hstgen.co.uk have some very in depth threads on this kind of subject, worth a read.

The speed set/cruise control thing, though not related to the original question, I believe some locos and units have this too but I'm not sure about the HST.
 

43096

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The driver controls the speed by varying the engine power. Don't know if any UK rolling stock has speed control other than Slow Speed Control (SSC) which was fitted for unloading at merry-go-round power stations. It makes it very difficult to move a train dead slow when you want to unload ballast or something similar.

Mind you it would have been very helpful for driving passenger stock through carriage washing machines, where precise control of speed is critical.
HST power cars fitted with the Brush electronics upgrade (all VTEC, EMT, NR, Grand Central and XC power cars, plus GWR's 43053/056) are, I believe, fitted with slow speed control for that very purpose.
 

hexagon789

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HST power cars/Class 43 locomotives are not fitted with any form of speed set. The Class 91s/Mk4 DVTs are however. The Class 43s are fitted with a five-notch power controller. If I remember correctly the notches give the following engine speeds in an HST:
0 - Idle - 950 rpm
1 - 1,060 rpm
2 - 1,170 rpm
3 - 1,280 rpm
4 - 1,390 rpm
5 - 1,500 rpm

Class 90, 91, 92 electric locos, Class 175, 180, 185 DMUs, Electrostars, Class 390 Pendolinos and some other EMUs have a speedset device. On most classes a speed is 'dialled up' - i.e. you set a dial to the speed you wish to maintain, however on the Pendolinos, you simply press a button when you reach the speed you wish to maintain. I also believe the speed set in a Pendolino doesn't use the brakes and so cannot control speed on a descent.
 

Skoodle

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Class 378s don't have any form of 'speed set', just a 3mph "Carriage Wash Mode".
 

whoosh

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Does each step of the speed controller give a particular engine speed?

Yes they do. Can't remember what the RPMs are, but 'idle' is the same as 'Notch one' (just with the contacts switched in for the traction motors), and also that the power car with ETS (Electric Train Supply) switched on, has 'Notch two' RPM in 'idle' and 'Notch one'.
 

gimmea50anyday

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Class 185 doesnt have a speed dial. When the driver wants to set the speed they move the pbc back to idle, then straight away back to notch 5. The TMS acknowleges this with a light that flashes above the cab windscreen
 

duncangry

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Many thanks for all replies. New question, is there a set number of amps for each notch on a class 43 speed controller??
 

craigybagel

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I'll have to check but I'm pretty sure the speed set on 175s doesn't work (judging by the condition of the buttons on some of the units!) and I'm sure I remember hearing from a 180 driver that they've never been used on those units either.
 

JN114

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Many thanks for all replies. New question, is there a set number of amps for each notch on a class 43 speed controller??

No, the power controller selects a specific engine RPM not Amps. Amps will be dependent on actual engine rpm, alternator load and so on.
 

trainmania100

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Class 377s have a speed set, you change the cruising speed using a switch which moves a marker on the speedometer and press the button to make it happen
 

craigybagel

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Class 377s have a speed set, you change the cruising speed using a switch which moves a marker on the speedometer and press the button to make it happen

But are drivers allowed use them? My understanding was former FCC drivers could but Southern couldn't?
 

robbeech

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Many thanks for all replies. New question, is there a set number of amps for each notch on a class 43 speed controller??

No, the number of amps is as previous posters have pointed out the amount of current which is determined by many factors.

Starting from 0 mph is the highest demand and will draw the highest current. As the train gets rolling the current draw will decrease somewhat at the same power level as it becomes easier to do its job. at Idle in a station there is effectively zero current (excluding ETS etc) and whilst coasting there is also zero current. Cruising at a regular line speed is by comparison very easy on the motors. Am i correct in thinking that going straight into notch 5 on a class 43 from standstill will overload things and the current will limit, lets ignore the likelyhood of wheelspin.

The class 91 (and Mk4 DVT) i believe has a continuously variable power handle so no notches, just a handle that you can put where you want it from idle to full.
 

Hairy Bear

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No, the number of amps is as previous posters have pointed out the amount of current which is determined by many factors.

Starting from 0 mph is the highest demand and will draw the highest current. As the train gets rolling the current draw will decrease somewhat at the same power level as it becomes easier to do its job. at Idle in a station there is effectively zero current (excluding ETS etc) and whilst coasting there is also zero current. Cruising at a regular line speed is by comparison very easy on the motors. Am i correct in thinking that going straight into notch 5 on a class 43 from standstill will overload things and the current will limit, lets ignore the likelyhood of wheelspin.

The class 91 (and Mk4 DVT) i believe has a continuously variable power handle so no notches, just a handle that you can put where you want it from idle to full.

The current is regulated by the load regulator so putting it into notch 5 straight away will rev it up to 1500 rpm and produce around 1500 amps down to the motors.Unless there's a serious problem with it , it will not overload and quite happily do it each time.
 

AndrewE

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Thanks all for the most informative posts. Sorry I misread the original question, but it was worth it!

I suspect that modern school physics doesn't introduce people to the concept of back EMF - that is the fact that an electric motor also acts as a generator, so if you put a voltage on a motor with a fixed load then the amps drop as it speeds up (because as the speed increases the motor generates more power - "back-emf".) The significance of all this is that on "classic" electric-transmission traction you ramp up the power until the ammeter says "enough," then let the amps dwindle as speed picks up and then wind it up a bit more again.

However that's probably mostly irrelevant now with AC traction motors, synchronous drives and other things.
 

43096

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The current is regulated by the load regulator so putting it into notch 5 straight away will rev it up to 1500 rpm and produce around 1500 amps down to the motors.Unless there's a serious problem with it , it will not overload and quite happily do it each time.

It is an utterly gash way of driving, though.
 

asharpe

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I suspect that modern school physics doesn't introduce people to the concept of back EMF - that is the fact that an electric motor also acts as a generator, so if you put a voltage on a motor with a fixed load then the amps drop as it speeds up (because as the speed increases the motor generates more power - "back-emf".)

It is taught to pupils doing a separate physics GCSE and who are of relatively high ability.
 

Kneedown

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EMT HST Power Cars have been retrofitted with a slow speed setting for use in carriage washers. As with the system fitted loco's working MGR trains, this controls power only, so the Driver does still need to use the brake to control speed fully.
 

driver_m

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HST power cars/Class 43 locomotives are not fitted with any form of speed set. The Class 91s/Mk4 DVTs are however. The Class 43s are fitted with a five-notch power controller. If I remember correctly the notches give the following engine speeds in an HST:
0 - Idle - 950 rpm
1 - 1,060 rpm
2 - 1,170 rpm
3 - 1,280 rpm
4 - 1,390 rpm
5 - 1,500 rpm

Class 90, 91, 92 electric locos, Class 175, 180, 185 DMUs, Electrostars, Class 390 Pendolinos and some other EMUs have a speedset device. On most classes a speed is 'dialled up' - i.e. you set a dial to the speed you wish to maintain, however on the Pendolinos, you simply press a button when you reach the speed you wish to maintain. I also believe the speed set in a Pendolino doesn't use the brakes and so cannot control speed on a descent.

A 390 does use the brake in speed set. It will maintain speed on a descent. Going round Northampton being a good example. On the long 75mph stretch the train can run away a bit and it will put brake in to keep at 75mph.
 

captainbigun

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A 390 does use the brake in speed set. It will maintain speed on a descent. Going round Northampton being a good example. On the long 75mph stretch the train can run away a bit and it will put brake in to keep at 75mph.

89/90/91 will also apply the loco electric brake to trim a bit of speed.
 

cossie4i

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I know it's not what you asked but a 66 has 8 notches and in notch 8 it is still reving less than a HST at idle.
 

Highland37

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Am I right in saying that the same engine is installed in the HST and Siemens Eurorunner? The MTU 16V4000? It seems to be capable of 4,300 hp if the Eurorunner ER30.
 
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