Loksound

[robcat]

Can anyone help with decoder selection?

I have Hornby Prairie class 61xx, Hornby 0-6-0 pannier tankGWR, Hornby 4-6-0 Castle and Hornby King GWR. All OO Gauge and all fairly new.

I want to fit sound decoders ( Not TTS) and like the look of Loksound V4.0.

My controller is NCE Powerpro. 5A capacity and there are seperate power supplies for points and all accessories so only locos are the power draw.

Can I get away with the Loksound micro? These are rated at 0.75A and according to Hornby the motors in the above locos are 0.2 - 0.4 A rated. That appears ok but I am not sure. I don't know the stall current as it is not easy to measure with my standard ammeter.

Standard Loksound are 1.0 A which would be ok for the Castle and King as I can fit into the tender with larger round speakers but it would be handy to use the same type of decoder .

Size is the problem as the non tender locos have very little room for sound decoders and speakers. I can use small 15 x 11 sugar cube which will just fit into the coal bunkers

I have looked at Zimo but Loksound seems the best deal for pricing and availability.

Any help please? I don't want to buy a decoder and blow it through overload

Thanks

[96RAF]

I would browse the RMWeb DCC Sound forum as some of the full fat sound decoder builders post on there as well as lots of info about ESU and Zimo sound decoders.

Rob

[robcat]

Thanks for that, will do

[2e0dtoeric]

Stall Current

[jane1707819582]

hi rob 

does the power pro have the ability to show track current? ,the powercab does, set this up drive a loco to a standstill the current will be shown on your cab . 

[Rog RJ]

 

does the power pro have the ability to show track current?. 

 

No, it doesn't AFAIK.

[robcat]

Thanks all

I have read that stall tests can damage modern motors even if held for only a few seconds, some have said a resistance test is the only safe way. I tried this by setting my meter to ohms and putting the probes onto the driving wheels of a loco ( off track, on bench and no power supplied). I tried this across the wheels i.e. left and right but the meter stayed at 1 so I touched two wheels on the same side, the digital meter flickered dramatically between 45 and 128 but settled around 65  so using  I = V/R  where V = 12 then i have 0.18 amps which does not sound right at all?  0.2A is bottom end of 0.2 to 0.4A normal operating range according to Hornby specs, not stall current. I am confused, the resistance test is quoted by people as a good test, am I doing it wrong?

If I do the manual stall test using DC do I need to do anything to the already installed DCC decoders ?

The "King" loco is the only one DCC ready but not fitted, can I do the DC stall test by the same method ? 

[2e0dtoeric]

You cannot do the stall test with a dcc FITTED loco. You have to put a blanking plug in instead, first, or all you can read on your meter is what the decoder is 'pulling'.

The same apples with the multi-meter across the wheels, all you can read is the decoder input resistance.

If you do the described method, with a DC or DC READY loco, the very brief stall load will not hurt the motor. Of course, if you keep it stalled for five minutes or half an hour on full power - - - -

If you have the loco running, and are watching the meter as you slowly increase the friction on the wheels, you can see the peak current as the wheels stop turning. There is no need to continue to keep it stalled! Let go, turn the power off, whatever. You've got the reading you needed.

Write it down before you forget watt it was!  (deliberate typo!)

[96RAF]

Putting both probes on the wheels on the same side is a direct short, not what you are trying to achieve at all.

Rob

[jane1707819582]

 

does the power pro have the ability to show track current?. 

 

No, it doesn't AFAIK.

i had chance to download the manual for the pro cab and yes it has the function to show track current

press 

prog and 6 (shortcut to the function) enter 1 

you can now read the current of the motors 

[Chrissaf]

...so using  I = V/R  where V = 12 then i have 0.18 amps which does not sound right at all?

.

The people who suggested measuring resistance of the motor have absolutely no understanding of Ohms Law at all. I studied Ohms law in depth as part of my apprenticeship college work.

.

Even if there is no decoder in the loco you cannot use Ohms Law to calculate the current drawn by the motor based upon its DC resistance. An electric motor is an inductor and therefore has reactance, and thus Ohms Law is not applicable. At best, Ohms Law on an electric motor can only give a very indicative level of current drawn.

.

[Fishmanoz]

You can use Ohm’s law but not this simple version.  You’ll have to “imagine” the more complex where resistance is replaced by reactance and the volts and amps get out of step (phase) with each other.

 

If only I could remember how to deal with the square root of -1, I‘d be able to explain it all to you. 

[robcat]

I read my info on meter calculations from the following forum post by Richard Johnson DCC Concepts, I believe he knows what he is talking about  re electricals:

The post is all about current draws and recommends a slip test as opposed to a manually held down loco stall test which can cause damage to modern motors even for a few seconds. Alternatively use Ohms law for the really 

Item (5) seems to be the one. Unless I have completely misunderstood.

 HiI have an interactive ammeter on my DCC system and install and test may locos.(1) it is rare for any Bachmann or Hornby loco made since can motors to draw more than 100mA when simply running with a reasonable train. Say 150mA when heavily loaded(2) the important spec for layout use is probably slip current - in other words, what current will the loco draw when placed against a solid object and the power applied so that the wheels slip. This rarely exceeds 200mA(3) Sound generally adds about 50mA, max 70mA.LEDs add very little (lighting) for example a ten coach train I did recently was only just over 300mA with aound loco as well - and that was 10x 8 LED per coach + loco lights + sound decoder + loco.Incandescent bulbs are current hogs (you can tell jsut by touching one - they get HOT!!! - avoid them - allow 50Ma per bulb - for example, that same train with only 2 bulbs per coach + 1 in the loco would have been about 1.5 amps!!(4) There are exeptions  to low current for locs older Hornby Dublo locos unless the magnets are replaced with neodymium in which case the current will drop from 500~700mA to about 200~250mA (and will run better)heljan which is a little higherolder models of every source (+15 years or so)Older Athaernloco's with open frame motors.(5) You can calculate potential max current easily. take the wires off the motor brushes and put a meter set to ohms on each terminal. this will give you the static resistance. Use ohms law to work out current draw. Use say 10v as the calculation point for this, its rare to ever run with 100% power on a layout. This applies to DCC too by the way - the voltage is always high but its only "on" part of the time, so the same rule of thumb applies.(6) Current draw can be managed. Keep motors clean and free of oil. Do not over oil motors ever, and never use sewing machine type oils on them as they creep - this means oil migrates to armatures, softens brushes, which means lower impedance which means high current/heat/damage to motor. (7) If you have over oiled don't be afraid to take the motor out and literally wash it clean - probably in a gentle solvent to kill the oil, followed by an alcohol bath. (8) It is better to NOT oil a motor if you cannot be sparing in applying it - enough for the head of a pin is enough for a motor bearing!For layout power handling I would calculate at 5 loco's per amp, but be relaxed about it - that would allow the odd current hog or several consists plus several loco's to operate as it has lots of lattitude.

Kind regards

Richard

 

JANE2      That doesnt seem to work on PowerPro.  The manual says 6 is 'set cab params'. I have to go to 4' Use program track', 6 is 'NCE effects' and then 1 is 'Output.' Nowhere in the menu navigation chart is Current or Ammeter. It must be different for Powercab.  It would be handy to have if I could find it ( If it exists)   Thanks anyway. 😢

[robcat]

Jane 2 

I have done further reading and Powercab can be set to replace the clock function ( under set cab params)with ammeter but not PowerPro as the smart booster which upgrades to 5Amp supply on PowerPro prevents this.

[jane1707819582]

I read my info on meter calculations from the following forum post by Richard Johnson DCC Concepts, I believe he knows what he is talking about  re electricals:

The post is all about current draws and recommends a slip test as opposed to a manually held down loco stall test which can cause damage to modern motors even for a few seconds. Alternatively use Ohms law for the really 

Item (5) seems to be the one. Unless I have completely misunderstood.

 HiI have an interactive ammeter on my DCC system and install and test may locos.(1) it is rare for any Bachmann or Hornby loco made since can motors to draw more than 100mA when simply running with a reasonable train. Say 150mA when heavily loaded(2) the important spec for layout use is probably slip current - in other words, what current will the loco draw when placed against a solid object and the power applied so that the wheels slip. This rarely exceeds 200mA(3) Sound generally adds about 50mA, max 70mA.LEDs add very little (lighting) for example a ten coach train I did recently was only just over 300mA with aound loco as well - and that was 10x 8 LED per coach + loco lights + sound decoder + loco.Incandescent bulbs are current hogs (you can tell jsut by touching one - they get HOT!!! - avoid them - allow 50Ma per bulb - for example, that same train with only 2 bulbs per coach + 1 in the loco would have been about 1.5 amps!!(4) There are exeptions  to low current for locs older Hornby Dublo locos unless the magnets are replaced with neodymium in which case the current will drop from 500~700mA to about 200~250mA (and will run better)heljan which is a little higherolder models of every source (+15 years or so)Older Athaernloco's with open frame motors.(5) You can calculate potential max current easily. take the wires off the motor brushes and put a meter set to ohms on each terminal. this will give you the static resistance. Use ohms law to work out current draw. Use say 10v as the calculation point for this, its rare to ever run with 100% power on a layout. This applies to DCC too by the way - the voltage is always high but its only "on" part of the time, so the same rule of thumb applies.(6) Current draw can be managed. Keep motors clean and free of oil. Do not over oil motors ever, and never use sewing machine type oils on them as they creep - this means oil migrates to armatures, softens brushes, which means lower impedance which means high current/heat/damage to motor. (7) If you have over oiled don't be afraid to take the motor out and literally wash it clean - probably in a gentle solvent to kill the oil, followed by an alcohol bath. (8) It is better to NOT oil a motor if you cannot be sparing in applying it - enough for the head of a pin is enough for a motor bearing!For layout power handling I would calculate at 5 loco's per amp, but be relaxed about it - that would allow the odd current hog or several consists plus several loco's to operate as it has lots of lattitude.

Kind regards

Richard

 

JANE2      That doesnt seem to work on PowerPro.  The manual says 6 is 'set cab params'. I have to go to 4' Use program track', 6 is 'NCE effects' and then 1 is 'Output.' Nowhere in the menu navigation chart is Current or Ammeter. It must be different for Powercab.  It would be handy to have if I could find it ( If it exists)   Thanks anyway. 😢

Apologies for the bum info robcat 

 

[2e0dtoeric]

Al that repeated text for a one-line answer!  😮

-

Wheel slip-test - won't give the max current draw, because as soon as the wheels begin to slip, the load will drop off, just like driving on ice. You have seen it on full-size steam loco's, once the wheels slip, traction drops to zero, and the driver has to shut off, wait for the wheels to stop spinning, then add a bit of steam (and sand), and hope.

[robcat]

 

-

Wheel slip-test - won't give the max current draw, because as soon as the wheels begin to slip, the load will drop off, just like driving on ice. 

 

 

I agree with that, but I think what Richard is saying is perform the test with a loco up against a fixed stop and slowly increase the power, watching the ammeter , and at some point the wheels will start to slip and ammeter reading will drop. That last reading before it drops is the max current. That way there is no danger of burning out the motor. We are trying to replicate a running fault on a layout such as a train hitting something or becoming jammed on a track. The final reading may not be as high as holding the loco down to stop wheel slip but in practice would that really happen? Probably the loco would derail, if there was a direct short the power booster would trip and shut down or the circuit breakers would trip on my layout.

[Rog RJ]

The worst case is that the wheels stop turning due to some obstruction, such as a track pin gets stuck in the mechanism or a coupling rod comes loose and falls off, jamming the motion.

[robcat]

That all got very complicated seeing as I only wanted to know the decoder type, obviously not that simple..

I will look around the web and see what size others have used in the same type of loco's I have and failing that do a manual stall test  very carefully. If the ammeter goes above 1 amp then I have a problem anyway as a larger rated sound decoder will not fit into the smaller tank engines.

I feel I will be ok with the ESU micro at 0.75A for the tanks and the larger ESU 1A for the tender loco's

Any more help would be appreciated if anyone has anything to add.

Thanks all for your input and Merry Christmas.

PS  I got a Hornby Bristolian Train Pack limited edition from Santa ---- now for the sound decoder!!!

[jane1707819582]

i agree the two decoders you have selected in the configuration you have decided will be adequate 

[robcat]

i agree the two decoders you have selected in the configuration you have decided will be adequate 

Thanks. Maybe I am overthinking all this, it's supposed to be a fun hobby after all.

No need to apologise for the "bum info" earlier. All info is valuable, that is how we learn from each other, thanks for your support.