Loco noise

[Rmw]

Sorry if this is already answered. I have two 00 gauge locos on analogue using a Hornby T7229 controller. Why do my locos make a noise and are bad crawlers but when I use  my 15V 2 amp power supply unit they are totally silent and are excellent crawlers?

[kevinlms]

33 minutes ago, Rmw said:

Sorry if this is already answered. I have two 00 gauge locos on analogue using a Hornby T7229 controller. Why do my locos make a noise and are bad crawlers but when I use  my 15V 2 amp power supply unit they are totally silent and are excellent crawlers?

You've already answered your own question.

The T7229 controller is an item designed for a cheapish train set for kids. Whereas your other supply is a properly engineered piece of equipment and so provides much better running.

 

Shove the T7229 in the cupboard for emergency use, or sell as is.

[DCB]

Not sure what 15 volt 2 amp  power unit you have but 2 amps too much for most 00 track and locos.  1 amp circuit breakers are usual,  Hornby Dublo used 0.9 amp I believe.    I have had fishplates glowing red on 2 amps running 5 loco lash ups of Triang Transcontinental locos.
As @Kevinlms says T7729 is cheap and may be PWM  (pulse width modulation) which provides pulses which appear almost like rectangular blocks on an oscilloscope rather than a rectified AC mains derived DC supply, which shows as a series of curved domes pulsing at Mains frequency  or  a smoothed DC supply which shows as a straight line. PWM pulses create quite a racket on older locos.    On Battery DC even old locos are eerily quiet.

Some old controllers have half wave feature which deliberately causes pulses  supposedly to improve crawling, it does not, but it does make it possible to run old Triang locos down hill slowly.
I personally am a big fan of Morley Controllers, they have a really excellent hand held add on and very good control.
If you continue to use the 15volt 2 amp I would recommend a 1 amp breaker between controller and track. Then again I recommend that to DCC users and they take zero notice and wonder why their point blades don't conduct after a while.

[Pete the Elaner]

8 hours ago, DCB said:

Not sure what 15 volt 2 amp  power unit you have but 2 amps too much for most 00 track and locos. 

 

Bit of a red herring there.

Voltage pushes current. The load (your loco) determines how much current is drawn, not the capacity of the supply.

15v is too much though.

Just because the supply can provide 2A, it does not mean you will overload the motor. It would do more damage if there was a fault though.

Heljan locos had a reputation of overloading Hornby decoders because they drew more than 1A under load when full power was applied.

Edited February 7 by Pete the Elaner

[Pete the Elaner]

On 04/02/2024 at 13:37, Rmw said:

Sorry if this is already answered. I have two 00 gauge locos on analogue using a Hornby T7229 controller. Why do my locos make a noise and are bad crawlers but when I use  my 15V 2 amp power supply unit they are totally silent and are excellent crawlers?

 

I agree with Kevin.

You are getting noise because your controller is not providing a very smooth output, so the motor is turning in very short bursts. This can cause damage to many newer motors.

There was a discussion about this recently.

I found a Gaugemaster handheld for £3 at an exhibition not so long ago (one of the cream coloured ones). They give a smooth output & provide a lifetime warranty & honour it without question, so a decent controller does not need to be expensive.

 

 

[DCB]

6 hours ago, Pete the Elaner said:

 

Bit of a red herring there.

Voltage pushes current. The load (your loco) determines how much current is drawn, not the capacity of the supply.

15v is too much though.

Just because the supply can provide 2A, it does not mean you will overload the motor. It would do more damage if there was a fault though.

Heljan locos had a reputation of overloading Hornby decoders because they drew more than 1A under load when full power was applied.

The Individual Loco draw is not relevant its when have too many  locos or  a short and then the amps do the damage to any poor connections, and particularly the point blade contact tags and blade pivots.  Almlost all RTR points were designed for 1 amp max and some of mine have been around for 40 years and haven't had blades cleaned for 25 years plus but always with 1 amp circuit breakers.  Others have been ruined by my 5  loco lash ups As I said my 2 X 1 amp power supplies have has fishplates glow red hot as 5 headed freights grind round, that is 2 X 12va power units each with a 1 amp breaker.    Not many UK based modellers have done that but it was a big problem in the states before DCC and typically 4 amps.    15 volts is low, the  old Hornby and H&M resistance controllers will show over 20 volts off load.    The  Morley will show a tiny fraction of a volt off load on minimum power   

[kevinlms]

5 hours ago, DCB said:

    15 volts is low, the  old Hornby and H&M resistance controllers will show over 20 volts off load.

An off load voltage has next to no relevance. The voltage ON LOAD and controllability is what matters.