Digitrax DS74 and Cobalt point motor

[shaunster]

Hi, 

Just testing a new Digitrax DS74 yesterday with 2 cobalt IP analogues, it will throw either one fine individually but cant throw 2 at the same time without the overload fault coming on. Can this DS74 really not power 2 of these at the same time? I tried with external power supply and track power, same issue.

 

Thanks

[Nigelcliffe]

I'd guess the Digitrax was designed against a Tortoise motor.   Tortoise motors draw significantly less current than Cobalts - this difference in current draw has been apparent for a decade or more.   

 

It should be possible to arrange things so one Cobalt causes the next to move, by using the switches on the first Cobalt to operate the second.  

[shaunster]

Even just connecting two cobalt's seems to cause overload at startup as the motors adjust a little sometimes. I think I'll look into something other than digitrax as I already have a load of cobalt motors.

 

The cobalt analogues are supposed to draw little anyway, 'Drive static <5mA, Active average <40mA'. Very surprised the DS74 cant handle this but you live and learn I guess.

Edited February 13, 2023 by shaunster

[Nigelcliffe]

Tortoise specs:   4mA moving, 16mA stall.     
The Cobalt pair requires between 2.5 and 10 times the current of the Tortoise -  40mA for the Cobalt when moving, compared to 16mA (static) or 4mA (moving) for the Tortoise. 

 

Its not the first time that the Cobalt has run into problems when used with devices designed for a Tortoise.   
 

 

 

 

[shaunster]

22 hours ago, Nigelcliffe said:

Tortoise specs:   4mA moving, 16mA stall.     
The Cobalt pair requires between 2.5 and 10 times the current of the Tortoise -  40mA for the Cobalt when moving, compared to 16mA (static) or 4mA (moving) for the Tortoise. 

 

Its not the first time that the Cobalt has run into problems when used with devices designed for a Tortoise.   
 

 

 

 

Its not an issue, I'm returning it now anyway but the Digitrax manual says suitable for slow motion motors, it doesn't mention only tortoise motors only. It would be useful if they updated the specs to say it can only handle those if it is a known issue.

[Nigelcliffe]

26 minutes ago, shaunster said:

Its not an issue, I'm returning it now anyway but the Digitrax manual says suitable for slow motion motors, it doesn't mention only tortoise motors only. It would be useful if they updated the specs to say it can only handle those if it is a known issue.

 

Tortoise = the default slow motion point motor in USA modelling, in production since the early 1980's.    
Cobalt = unknown product and brand in the USA. 

Digitrax are a USA company.   They're not going to know anything about products only sold in a little island thousands of miles away (the UK).  

 

- Nigel

[shaunster]

Fair enough, still no mention of it on UK retailers sites and after all I bought it in the UK and it states suitable for 4 slow motion motors. Anyway, I got 2 new Yamorc switching modules with DCC concepts 3 pin to 2 pin converters and it works perfectly with 4 cobalts so far. Also using the yamorc feedback modules, highly recommended.

[DCCconcepts]

On 13/02/2023 at 10:43, Nigelcliffe said:

Tortoise specs:   4mA moving, 16mA stall.     
The Cobalt pair requires between 2.5 and 10 times the current of the Tortoise -  40mA for the Cobalt when moving, compared to 16mA (static) or 4mA (moving) for the Tortoise. 

 

Its not the first time that the Cobalt has run into problems when used with devices designed for a Tortoise.   
 

 

 

 

 

Just to clarify some of Nigel's information.

 

The Cobalt Analog IP does take more current whilst moving and can cause issues with some devices - even including the older DCCconcepts AD1 and AD4 decoders (*), but the static current is around 5mA - one third lower than a Tortoise.

As a point motor spends most of it's time in the static position, then this is quite satisfactory and a user with significant number of them will see the benefit of using a lower rated power supply to power them - particularly for analog only use.

 

(*) the original AD series was replaced with the DCCconcepts AD-FX range of decoders. These are more than capable of driving two Analog IP motors and the AD-FX is shortly to be replaced by another updated AD series decoder with plenty of power.

 

Best Regards.

The DCCconcepts Team