MTH Z4000 Voltage To Run DCS

I would say 18 or 19 volts. 

Will running higher  than 18 volts cause locomotives to overheat, especially pulling long loads or running for 2 to 3 hours at a time? Never had this problem when running Z1000 transformers which put out about 18 volts maxed out.

I sometimes go up to 20volts, if I have more than one locomotive on the same main line plus passenger cars. I have been told that voltages above 19 volts are harder on smoke units, but since I never use smoke anyway, I have never had any problems at voltages above 19. I find that my Sunset/3rd Rail steam locomotive models run VERY nice at 18 to 19 volts.

I've always set it at 18v and never had a problem, but never set it higher either

Joe B

I just put the throttles all the way, but then I very rarely run more than hour. always more than four locomotives. When I check the voltage at track it's about 18 volts. 

Never had a need to set it higher than 18.

I have a fairly large layout and alot of track, 75 % is solid rail Atlas.  running  2 and four motor engines I set it all they way up. My logic is that there is a lot of track, I have grades, and with passenger cars added there is alot to power. 

The problem with too much voltage on the tracks is you're also running closer to the limits of the electronics in the various locomotives and other electronic cars.  For instance, TMCC/Legacy specifies a maximum of 19 volts.

I put mine to 16. Easier on the light bulbs. Everything runs ok.

algomafan85,

   I have to agree with Steve, my fairly large 5 level layout is wired correctly and runs everything at 16 Volts.  I now have LED lights in my older Lionel switches and controllers and the 16 volts is actually more than I need for constant running of my DCS controlled layout. 

PCRR/Dave

The voltage at which you need to set the Z4000 also depends on the votlage that you get thorugh YOUR wiring and YOUR track to the loco.  If you have greater voltage drop, you'll have to apply higher voltage to get adequate power at the far reaches.

Hi, I usually run at 18 volts on my home layout.  I set if all the up on the outdoor G&O layout.  Long wiring runs and dirty track outside reduces the voltage reaching the engines.

People say that they run their engines for several hours at a time.  I have never seen this done by anyone including at train shows.  (The only exception to this was the HO display at the Chicago Museum of Industry where trains operate on a continuous loop.)

Most operators get bored with the same train after awhile and change it out for something else.  Does none stop running for hours on a home layout really happen?

Joe

Will running higher  than 18 volts cause locomotives to overheat, especially pulling long loads or running for 2 to 3 hours at a time? Never had this problem when running Z1000 transformers which put out about 18 volts maxed out.

The motors on PS-2 and PS-3 locomotives never see the AC power applied to the track.  AC track power is rectified to DC by electronics on board the locomotive.  The DC motor is fed DC power at no more than 12 volts.  Locomotive speed is not controlled by varying the voltage but by modulating the width of 12 volt DC pulses sent to the motors.  If your track voltage is 14, 16 or 18 the motor will never see a difference.  

18 volts from your Z-4000 is just fine.  If you run the same trains on the same grades as with your Z-1000 there should be no difference in locomotive performance.

I'm also in the 16-volt group (Z4000 transformer).  Everything runs just fine (DCS/Legacy/TMCC engines).

It's not the motors that are of concern here I would imagine, the primary danger of over-voltage is the electronics!

I've always used an 18 voltage setting.

When running at 18 volts the amperage draw will be lower than running at 16 volts. So I don't know which is the best on electronics of the engines.

Higher voltage or higher amps??

Will the higher amps make more heat on the boards??

I don't really know.

I'm trying to figure out how running at 18 volts lowers the current.  Since the electronics has to dissipate the excess voltage, it appears as heat in the electronics of the engine.  The first component in most electronics packages is the full wave bridge rectifier.  I don't see where you'd be using less current, but you'll be generating more heat.  In addition, of course, you're operating closer to the margins of the electronics.

I'm not seeing the real or perceived advantages here.

If I'm running trains from the Z4000, raising the voltage always results in increasing the amperage.

If loco slows down, as on a grade, the amperage increase as the reverse EMF generated by the motor drops, without me touching the throttle.

If motor voltage is controlled by pulses, as gunrunner says (I don't diagree), then I don't think that there is much heat generated by the process (power either on or off), in contrast to using a resistor

Ted Hikel said that. He knows more about this stuff and how it works better than anyone who ever posted on this forum. Maybe, even MTH1. IMHO.

How it actually works is: the AC is regulated at the FWBR to create positive DC voltage.  The 18VAC in will give about 22VDC out.  This Voltage sits at the pins to power all the lights, couplers, Motor Relay for the Motor FET.  22VDC at 18VAC.

The FETs then regulate the current flow and effective Power to DC Ground (PCB Ground) for all the powered items.  Two separate diodes rectify AC to DC for the 5V Regulator that is a microcontroller.  This 5VDC powers all the U chips but 3, the LEDs, the Motor Relay Coil, Tach Reader, and Smoke Fan and the 3.3VDC Regulator for the 2 processors and the Memory Chip.

My experience powering and testing boards with a Z-4000 and the bench tester is that at lower voltages 10-12 VAC the current drawn is higher when operating smoke and motor.  As I raise voltage to 14-18V the amps fall off despite the motor turning faster under No Load.  This relationship makes sense since the power required is the same, and at lower Volts the amps are higher and vice versa.  Just like a pump rated for 115 or 220VAC.  The current is reduced if operated at the higher voltage.

Having said that as the voltage is raised in conventional on a loaded engine on the track, current will go up because the motor conditions change and the train wants to go faster.

I don't think much harm is done either way, but above 16VAC there is enough power available to properly power the accessories.  At lower voltage conditions the lights seem to flicker some and the motor struggles to turn, and if you turn up the smoke volume you will see the motor slow as the heater element places a greater load on the Positive Voltage circuit.

I would love to hear from the design guys if the program recognizes actual track voltage and regulates the PWM based on that, or if it is a set algorithm.

Going to higher voltages 20-22VAC just results in higher DC available.  Not sure the system needs it, and in the event of a derailment, bulb blowing, or a wire shorting, you just have more potential energy available in a spike to damage some of the FETs and Line Drivers and Opamps.  Just ask the guys that short the board to AC Ground:-)   G

For the same reason, I also limit my transformer output to 16V on my DCS/TMCC tracks.

Setting the transformer voltage and what the engine sees are 2 different things. The voltage at the track is what the engine sees. A 2 volt cushion is pretty good for medium to great electrical wiring.

GGG thank you for the informative post. I did not understand a couple of the anachronisms. FWDR, PCB ground, PWM 

I think Passenger car bulbs if not LED are 18v. Running higher voltage through them will decrease there life.

Jim,  FWBR = Full Wave Bridge Rectifier.  The Square diode with 4 legs on 5V boards, or the Wafer on 4 legs on the 3V board.  PCB Gnd = Printed Circuit Board Ground or DC Ground.  For MTH this is not AC Outer Rail.  The DC ciruit is a separate circuit that is powered from AC transformed to DC, but with out a common ground.

PWM= Pulse Width Modulation.  The turning on and off of the FET to limit the power/Voltage a device sees.  The Lights which are 6V bulbs have over 18 VDC going to them, but since the ground is only connected in pulses the effective voltage is around the 6VDC level.  Same with motor, heating element, Coil Couplers, etc...  G

Running higher voltage through them will also increase the current.

One lap around the layout is about 600 feet with a grade around 30 plus ft long raising about 10 inches. often the three locomotives are run constantly for several hours at a time on each mainline or in switching duties. Since going to the Z4000s we have noticed many locomotives overheating and totally shutting down. When left to cool for a bit they restart  and run fine. We just never had this occur  when using Z1000s running at a max of 18volts. Since we installed the Z4000s most locomotives have been run at 18 to 22 volts. The question is although the Z4000s are capable of more voltage than the Z1000s should it not be run at no more than 18volts to lessen the chance of whatever componet is overheating?

So much for the higher voltage not creating more heat inside the locomotive.

I guess I would ask, once you switched from the Z-1000 to the 4000 did folks add a few more cars to the consist?  What is the amp load showing on the meters of the Z-4000.  Make it a little more scientific and let us know what you see/find.

Run for a day at 18V and record amps and see how it does.  Next day run the same train/load but at 22V and record amps and how it does.

The other difference here is the Z-4000 is pure AC and the Z-1000 uses a modified wave form I believe.  So there may be a difference.  G