Lionel CW-80 Voltage Spike

I tested it with a one shot trigger and obtained the voltage spikes. I found one peaked at 27.2 volts and the other at 37.4 volts both would simmer down around 13.volts  the spike is contributed to the trans former power up voltage and you mus be aware of the spike to keep from blowing the circuits. It has to do with the magnetic flux on power up you need to be aware of it when using the accessory voltage ports. All transforms will sipke on start up and need to be watched. using the variable output there is now problem. You would need to put a pulse limiter on the output. 

How long does this spike last until it calms down to the set voltage. I could easily put an on/off switch after the output of the transformer but before the accessory until the spike was gone. I really don’t feel like changing out a transformer.

I’ve used cw80s for switches and accessories and never suffered damage. The spike must be pretty quick.

What transistor is used in the DZ1008s? Usually 50 v is a minimum for transistor voltage rating. If this is a typical hazard, some rethinking on ratings or circuit protection would be good.

Sounds to me like the control circuitry for the accessory output is not operating quickly enough to keep the voltage from spiking.  You might be able to try a snubber capacitor across the accessory output to limit the spike.  I would start with 0.1 uf non polarized.  You will need the o-scope to determine if this helps.  I am also curious to know if a spike is seen on the variable output.  My guess is that there will be no spike if the throttle is set to zero on turn-on.  I don't have  a CW80 on hand so I can't make any measurements here.

Regards,  Phranzdan 

Phranzdan: I am using the throttle now and have no issues.

CJack: I don't know what transistor is used in the DZ-1008. The voltage spike does not affect the DZ-1000 motors nor Atlas O motors or snap relays for obvious reasons. It seemed to be only the 1008 relay. I alerted D Zander but have not heard back as yet.

Rod: I don't know how long the spikes lasts (probably only msecs) but I would think an on/off switch after the transformer would work just fine.

Joe

CJACK - do you have any issues with light bulbs on your accessories?

Joe

I'd use a TVS across the output of the transformer.  A popular one in use here is the Littlefuse 1.5KE36CA. FWIW, a 34V peak spike shouldn't be a major factor, that happens frequently in our environments.

John:

What does TVS mean and I assume the diode you mentioned stops the spike from going through the power line?

Joe

The TVS is a Transient Voltage Suppression device that whacks voltage spikes that exceed it's clamping rating.  It's connected across the output of the transformer to suppress any excessively high voltage spike.

Model Structures posted:

CJACK - do you have any issues with light bulbs on your accessories?

Joe

No. But if I powered them with the A output,  they oscillated in intensity a bit. The accessory side was more stable.

i’m looking to purchase a CW 80 if anyone has one for sale if it needs minor repair that’s ok cause i’ll be doing some modifications on it anyway

I added the TVS diodes mentioned above to my CW-80, Type S, and my VW last January.  My little railroad is happy now.  They are cheap insurance.  Don't forget properly sized circuit breakers.  

I must have some good luck on my side. I don’t have a big set up but noticed my postwar steamer smoke output was noticeably better on my CW 80 than it was on a TW 175 watt I have. the two CW 80 I have are both the “G” series

Stan, I have no idea how that got in there, but I fixed my link.  I'd suggest you remove that link from your quote as well.  I don't recall ever linking to Allied previously, I normally refer to parts like this on Digikey or Mouser.

I just deleted my post so I think we're good.  For anyone ordering this part, if you do a web search to shop around, use the following search term:

1.5KE36CA

make sure you have the letters CA at the end.  Pricing is all over the map - from 10 cents to well over $1 each.  I see someone on eBay even invoking "Lionel" in the title!    This is a generic part.