Capacitor discharge units with R8247

[Spireblade]

I have installed various point motors on my layout but some lack the oooomph to work properly. When I used DC I only needed the 1 unit for all the motors. Am I right in thinking that I might need 1 per motor with DCC.

 

(RM + R8247 + surface mount motors)

 

Thanks again.

[Flashbang]

Hi

The Hornby DCC accessory decoder includes a built in CDU.

You cannot add a CDU directly to the output of the decoder. One way is to operate a 12volt relay momentarily from the Decoders output and via the relays contacts feed a seperate power supply and CDU to operate the motor.

I think in your case I would look at the size of wire used from accessory decoder to the solinoid point motor. This really needs to be 16/0.2mm equipment wire minimum.

 

You should also allow a couple of seconds between each point operation to allow the internal CDU to fully recharge.

[ff2nd]

The R8247 effectively IS a CDU. There should be no need to use a separate unit. As Flashbang says, give it up to four seconds between activations, to allow a recharge. The other thing is to make sure that your point motors are perfectly aligned. Misalignment can cause extra strain, meaning the unit has to work harder to drive the solenoid.

[Spireblade]

Thanks. What happens when starting Railmaster? They all seem to set themselves in sequence, it's under normal operation, especially the ones wired in pairs that seem to struggle. I'm using wire of a very similar type to the actual motors.

[Chrissaf]

Try increasing the value of the 'Points Timer' in the Railmaster.INI file to give the integral CDU more re-charge time.

.

/media/tinymce_upload/30b44c17ed1d4bcbf0080423a86a466f.jpg

.

[Spireblade]

Thanks Chris, I'll give it a go.

[Pete172]

Hi, if you are (as you say) using similar wire to that which comes fitted to the surface mount point motors, then that could be adding to the problem.  If the point motors are situated any real distance from the power source, then you should use 16 / 0.2mm wire throughout the circuit to the motor if possible, as Flashbang suggested above. If you are using the Hornby R8243 motor, the wires that come attached are very slim and won't pass much current over distance. These little motors draw a lot of current !, especially if you are trying to fire two at once....

Also - as Chrissaf suggested, increase the time between point motor firing , thus allowing the CDU to re-charge correctly. The Hornby accessory decoder R8247 ( yes I have 5 of them), is not the most powerful around in terms of CDU output, I had many issues when first using them and had to use 16/0.2 strand wire throughout my layout, but even then my double point set-up would not work correctly when both motors were fired together, so I eventually had to fit 24/0.2mm wire to both motors, only then would they fire reliably together.

Hope this helps..

[Spireblade]

Thanks