Train Engineer on HO Scale - Questions and confusion?

[LittleRedTrain]

Hi all.

I've got an old Aristo Train Engineer (ART-5470, one of the two-channel versions) and as I no longer have a use for it on my G Scale (having switched to LGB kit) I thought I'd give it a go on a friend's HO garden railway to see if it was any use to him.

My understanding was that this should work, because as long as we only used a 12V DC power supply (in this case, the track output from an HO Gaugemaster controller) the TE receiver shouldn't output voltage/current levels that could damage HO scale motors.

However, when we tried it, we discovered that, despite the 12V DC input, the output was coming out on the meter as 19V DC, regardless of the setting of the handset.
We did try it with a fairly robust loco and it seemed to work fine, but he was loathe to try it further until we knew what was going on and whether there was a risk of burning out more sensitive locos (those with electronics onboard).

I did wonder if it had somehow gone into PWM mode, but the switch was most definitely in the 'linear' position.
Also, how does that explain the output voltage being higher than the input, I didn't think the receivers had a transformer in them.

Can anyone shed any light?

Many thanks
Daniel

 

[Neil Robinson]

If the power supply isn't smoothed dc it can have a peak value of up to around 1.4 times the nominal (RMS) voltage.
The Train Engineer has an output capacitor that can store energy and on no or very light loads the voltage output can be around the peak input voltage. It also means that no load meter readings on the output of the Train Engineer can be misleading and confusing. I suggest you measure the voltage on the track when a loco is running and check the maximum voltage under these conditions.

 

[LittleRedTrain]

Thanks, I'll give that a try. The capacitor would certainly explain the behaviour.

 

[spike]

If it's the 2000mfd cap it is connected across the input dc when in PWC and across the load when in linear.
In linear it smooths the output, in PWC it keeps the voltage stable.

I believe Aristo made a special HO version purely for the lower voltage motors.
According to George Scheyer it was a small board that fitted a NMRA 8pin socket.

 

[Brixham]

Many years ago I helped a friend run his Triang TT layout. We did have conventional controllers, but also had two of the later 10 channel units. We ran the trains most of the time using the Aristo hand helds without any apparent damage. I would think that the power supply arrangements between the two models would be similar, just the 10 channel/10 loco capability on the later unit being different. The TT motors were all 3 pole open frame types.

Malcolm

 

[Brixham]

PS I have no idea if we ran linear or pulse...but maybe we were linear. We didn't have the fans...and the unit didn't get hot. maybe it was pulse...
Powered the units from a normal dc out from a power pack, never measured the voltage, but the trains ran at normal speeds.

Malcolm