DZ-2500 Power Supply

if you connected non-derailing yellow and green wires to the short isolated track spurs then two diodes one on each wire.

@AlanRail posted:

if you connected non-derailing yellow and green wires to the short isolated track spurs then two diodes one on each wire.

If I remember the instruction Dennis Z. gave me, one wire has a diode and the other a resistor.  Speaking of the yellow and green. 

@AlanRail posted:

if you connected non-derailing yellow and green wires to the short isolated track spurs then two diodes one on each wire.

@Bryant Dunivan 111417 posted:

If I remember the instruction Dennis Z. gave me, one wire has a diode and the other a resistor.  Speaking of the yellow and green.

The only diagram with diodes I have seen are the instructions for the DZ-1000.  The diodes were to stop the switch LEDs from flickering.  Is there a diagram on this protection circuit somewhere?  Thanks.

I'd contact Dennis at Z-Stuff.  I remember the diagram and there were two diodes, one from each non-derailing rail.  I forget which way they were oriented, but there are definitely two diodes.

Thanks everyone for your replies. I used the diagram for the non-derailing feature from another post on this forum to connect the diodes. (band on the diode goes toward the isolated rail). My question is more on how to fuse the power supply used to power the switch machines themselves. How did you handle this?

What about the 2500 requires a fuse...Or what are the possibilities of a short and where?

I'd allow maybe 75-100ma for each switch machine max, and fuse accordingly.  If you have ten switch machines on your power supply, a one amp fuse would be appropriate.  Chuck, I'm assuming the short is more likely in the wiring than the switch machine.  Of course, the switch machine could develop an issue and draw excessive current, there is a small motor, power supply, and microprocessor in there.

I think the case of death for DZ-2500s is much more likely to be spikes or other transients on the power line, rather than sustained overloads that a fuse would handle.  

If there are likely to be spikes on the power supply line, like an accessory with a solenoid or vibrotor, then a TVS or RC filter across the DZ-2500 red and black terminals might be helpful.  Or maybe better, put that protection across the power terminals of the accessory that might generate those spikes.

I had a location near a Lionel mail drop (solenoid) where DZ-2500s on the same power bus would regularly expire, until I installed some protection.

@CAPPilot posted:

The only diagram with diodes I have seen are the instructions for the DZ-1000.  The diodes were to stop the switch LEDs from flickering.  Is there a diagram on this protection circuit somewhere?  Thanks.

My memory is shot   I re-found the post with the info on the diodes, says nothing about resisters.

Here is a copy of the diagram for the 2500’s.  It shows 2 diodes. Sorry it’s not vertical.

@Professor Chaos posted:

I had a location near a Lionel mail drop (solenoid) where DZ-2500s on the same power bus would regularly expire, until I installed some protection.

The only thing on the power bus for the DZ-2500 switch machines on my layout is more DZ-2500 switch machines.

@Tanner111 posted:

Here is a copy of the diagram for the 2500’s.  It shows 2 diodes. Sorry it’s not vertical.

I Remembered the resistors were recommended by Custom Signals.  The resistors had to do with his system.  I have diodes on each also.  Good insurance for sure.

@Bryant Dunivan 111417 posted:

I Remembered the resistors were recommended by Custom Signals.  The resistors had to do with his system.  I have diodes on each also.  Good insurance for sure.

Actually, I believe the resistors have to do with a possible derailment and spikes traveling up the non-derailing leads and killing the DZ-2500.  That came right from Dennis Zander, so I suspect it's probably the real reason.

Below is strictly about turn on and not derailment but may be of interest anyway.

I do not work with the DZ2500 but have done quite a bit with the DZ1000. The specs on this machine say 25 volts max. I blew up quite a few machines before I figured out the ACC post of a CW80 I was using spiked at 31 volts at turn on before settling down to 18 volts (it took a smart Navy tech and a big oscilloscope to figure this out). Dan actually tested two CW80's I had and both acted the same.

It would be a good idea to find out the max volt rating of the DZ2500 - should be in the paperwork that came with the machine. I would also ask John for a good solution to protect from voltage over-spiking. In my case I switched power to a handle on the transformer. The voltage is set to zero on turn on and raised to the proper voltage.

Side note - the DZ machines work fine at voltages as low as 12+ but I also have Atlas O switch machines plus their 200 relays. These require a higher voltage for proper functioning - about 18 volts.

Dennis sent me an email:
1. it is ok to power the DZ2500 with either AC or DC.  - 14-16V. 18V will over heat the machine
2. For DZ1000 - AC only - 14-16VAC - 18VAC will present long term problem

I am going to have to remove all the Atlas O switch machines. The 200 snap relays seem to work ok at 13VAC so I will keep them but these relays are no good if you want to connect non-derail to the DZ1000. They will keep 'buzzing' as the entire train consist goes over the isolated track and will over heat.

Dennis Zander suggests 12-14 VAC for the DZ-2500, and I suspect he knows best.  He said they work on 18 volts, but tend to overheat.

Joe, GRJ.....

Your post started me thinking (do you smell smoke? ).

My layout is split up into power districts and uses 4 PW ZWs to power those districts.

I recently swapped out the 4 thermal circuit breakers with 8A magnetic circuit breakers. I also have installed TVS diodes on the TIU outputs and at each location where the power splits off to each of the power districts.

The 4 PW ZWs are plugged into a switched power strip. That way I can turn every thing on using a single switch.

Anyway.....I experienced 2 situations where when I turn the power on at the power strip, 1 or 2 of the circuit breakers would trip (this never happened with the thermal circuit breakers...not fast acting enough?). And, the breakers that tripped where not the same breakers. I reset the breakers and everything runs fine.....no shorts.

I'm wondering if the ZWs I'm using are producing a voltage spike when powered on and never knew it?

If that's true, what can be done to minimize the risk (I have enough electronics knowledge to get me in trouble )?

Whadya think?

PS....I failed to mention that ZWs are all set to produce 18V. I do not "throttle" them up.

I'd be more likely to suspect something that is powered by the ZW's has an initial starting surge load, I can't see the ZW's producing a large spike. Obviously, the only way to know for sure is to measure it.

It can't hurt to have a TVS across each of the transformer outputs to make sure you aren't getting a large spike, and it's good practice.

1500W 33.3V TVS at Digikey

Thanks GRJ.....

I will check my stash of electronic components and add those TODAY.

Funny thing is....discussions I've seen/read were always about voltage spikes coming from the direction of the track.

Never thought about spikes coming from the transformer.

That's what I LOVE about this forum.....I learn sumthin every day!

Spikes can come from any collapsing magnetic field around a coil, so it can come in either direction.

@Junior posted:

Joe, GRJ.....

Your post started me thinking (do you smell smoke? ).

My layout is split up into power districts and uses 4 PW ZWs to power those districts.

I recently swapped out the 4 thermal circuit breakers with 8A magnetic circuit breakers. I also have installed TVS diodes on the TIU outputs and at each location where the power splits off to each of the power districts.

The 4 PW ZWs are plugged into a switched power strip. That way I can turn every thing on using a single switch.

Anyway.....I experienced 2 situations where when I turn the power on at the power strip, 1 or 2 of the circuit breakers would trip (this never happened with the thermal circuit breakers...not fast acting enough?). And, the breakers that tripped where not the same breakers. I reset the breakers and everything runs fine.....no shorts.

I'm wondering if the ZWs I'm using are producing a voltage spike when powered on and never knew it?

If that's true, what can be done to minimize the risk (I have enough electronics knowledge to get me in trouble )?

Whadya think?

Which model magnetic breakers are you using?

I use the “Fixed” 14VAC on my Z4000. Never had a problem with the Dz2500.

Donald

@3rail posted:

I use the “Fixed” 14VAC on my Z4000. Never had a problem with the Dz2500.

Probably not, that's the recommended voltage to run them at.

I used a. separate 12 volt DC power supply on mine and a lot of the little glitches went away that I had experienced before when running them off the track power. this suggestion came from Denise at Z stuff. I also gave up on the data wire as if any switch machine on it malfunctioned none of them would work. I was waiting for Lionels new switch controller for the DZ-2500 to come out but it got set back several times to I sold the 2500s and installed some DZ 100s and tortoise switch machines and ran them off Several SC-2 controllers a much more trouble free arrangement.

Rick in an interesting twist, I've had a long conversation with Jon Z. of Lionel fame about the DZ-2500 and the CSM2 boxes.  Turns out the serial data out of the CSM2 causes some odd issue at times with the DZ-2500 and locks them all up.  I dropped back to using the DZ-2001 data driver, and I've never had the problem since.  The issue I experience was only on power-up, if they worked after powering up, all was well.  However, if I powered up the layout and the the DZ-2500 were non-responsive, all of them were dead.  A power cycle would normally cure it.

I have not gone back to revisit the issue, but I suspect if I delay the power-up of the DZ-2500's for a couple of seconds all will be well, just haven't gotten around to it yet.

Interesting thought about the 12VDC power, I am still using AC.

@Tommy44....

I'm using the Sensata-Airpax Model PR11-0-8.00A-XX-V-ND breaker. Couldn't find them in stock anywhere but DigiKey ordered them for me. Took several weeks to get. Digikey did not charge my CC until they shipped. Worked out great!

@Rick Rubino posted:

I used a. separate 12 volt DC power supply on mine and a lot of the little glitches went away that I had experienced before when running them off the track power. this suggestion came from Denise at Z stuff. I also gave up on the data wire as if any switch machine on it malfunctioned none of them would work. I was waiting for Lionels new switch controller for the DZ-2500 to come out but it got set back several times to I sold the 2500s and installed some DZ 100s and tortoise switch machines and ran them off Several SC-2 controllers a much more trouble free arrangement.

Rick:
I like the idea of DC power however do you use and if so how do you set up non-derail for the DZ-1000's since they would need to be connected to track ground for the non-derail option to work?

John:
I guess the basic question is can DC and AC run off the same common (gnd)?

No problem at all having a common ground for AC and DC supplies.

John:

Forgot to ask - how would one connect the TVS diode to a power supply - I assume in line with the power output?

In parallel. Across the two power leads. From A to U. From Hot to Com.

Thanks Chuck