Large Scale Central

RCS issues...whoooooooooa

Electronics Power and Sound
#1

So I put the RCS system I received a few weeks ago (thanks Bruce!) into the LGB 2-4-0–and I’m getting some really strange readings off it.

First, I wired it up, double checked the power polarity, and it’s fine–plugged it into an 18V drill battery to test it (14.8v lipo still on the way) and it drained it in five minutes, power light doesn’t come on, nothing.

I thought, hmm…

Tried it with another battery and read it with a multimeter. 5+ amp draw at 18V – yikes!–dropping to 3 amp draw as the battery wore down. Nothing smells fried, wiring’s cold. Resistance in the RCS board starts at 500 ohms and climbs rapidly past 1300.

Any ideas, guys? This needs to be running by Ric’s this coming weekend. Loco wiring checks out–no shorts anywhere. Doesn’t appear to be a short in the tender, either.

#2

Which RCS controller is it?
As in the ESC model #. It will be written on the pcb.
Are you sure you have the track pick ups disconnected? All of them?

If nothing is getting hot and the battery is getting flat it is most likely somewhere in the wiring between the battery and the ESC.

#3

Pretty sure it’s a E-3HV–too late to go outside and check. It’s definitely not a 9HV.
Track power pickups are DEFINITELY disconnected–there’s a DPDT switch in there to switch from track to battery and vice versa. It runs on track power, not on battery.

#4

If you don’t have any instructions I will be able to have a poke around my computer for the instructions if you could show me a picture of the unit in question.

#5

I do have the instructions–they’re labelled “RCS # “BASIC” & ELITE” Motor Drivers".

The last page is labelled “Wiring the ELITE-3 R/C Throttle”.

That help?

Positive battery input is in the + terminal (first pin) on the four pin plug, negative on the -.

#6

So I double checked my wiring–loco checked out, when I ran my motor wires to a transformer it worked fine.

Ripped out all the tender wiring and redid it–made sure everything looked good, no shorts, nothing.

Multimetered the RCS board on the power in ports–infinite resistance, as I expected to see, everything looked good.

Plugged the battery in–0 amp draw as expected, light went on. I hit the increase speed button on the transmitter, and the capacitor immediately ruptured outwards with a huge KAPOW and a lot of smoke.

I assume this is totally dead?

EDIT: And it’s an “ELITE-2”, which doesn’t appear to be covered in the manual I have…?

#7

It can likely be fixed if you get it back to me.

#8

I’d appreciate still knowing what the problem was and why it blew up–otherwise, it risks the same thing happening again even if repaired. Do you have any thoughts on this at the moment, or would I have to in fact ship it back first?

I understand if you’re reluctant to guess, but it would make me feel a bit better.

#9

Dear Robbie,

Reverse polarity on an electrolytic capacitor can cause it to heat up and explode.

It’s possible you connected your battery up in the wrong direction (polarity).

Less likely, board stuffed with caps in the wrong direction (polarity) before soldering at assembly.

Hope this helps.

Joe Satnik

#10

Battery WAS plugged in properly–there’s no guesswork on this, it turned on and an LED lit. The capacitor only blew when I tried to apply power via the controller.

#11

Hi Robbie.

There is usually only one polarised electrolytic cap on an RCS ESC. It is diode protected on the power input circuit.
The are only two ways they can blow, wrong polarity which is not possible in this case, or too much voltage.

I cannot guess as to what went wrong without seeing it. Perhaps a photograph to start with of how it was mounted inside the loco.
If a component failed I will repair it under warranty.

#12

I’d be interested to hear the outcome of this one.

The first post, a fresh battery drained in 5 minutes. Assuming 2 amp hours, then this could have been a 25 amp draw?

Certainly something would have gotten very hot to drain all that current in 5 minutes.

Reading the subsequent posts, something really does not add up here.

Regards, Greg

#13

Hello Greg.
So far I have not heard from Robbie.
I have no idea what happened and until I can see a pic or get the part back I cannot hazard a guess as to what went wrong.

Unlike some other brands, component failure on RCS ESC’s are actually quite rare.
In the 3,000 plus ELITE pcb’s that have been made since I started using the NSD H Bridge, there has been just one failure of an H Bridge in the field that I know of. That was caused by resting the powered up pcb on a metal surface and shorting it out.
Switching transistors have failed regularly. Usually because there was no dropping resistor applied in the circuit when controlling LED’s.
The only times I have heard of caps exploding have been as a result of too much voltage being applied to the input.

#14

Yep, I’ve been reading the forums for 10 years, your component failure is really rare, in fact I cannot remember ever reading about an actual failure at all.

Something seems fishy, as in my rough calculations above, a 25 amp draw? Something would have smoked/smelled/overheated.

I have tried to drain a battery in 5 minutes, burned my fingers and did not accomplish it.

Like I said, I’m interested to hear the outcome.

Greg

#15

Sorry–I’ve been bogged down with four midterm exams in the past three weeks.

The capacitor did in fact blow up, while using this battery: http://www.sears.com/shc/s/p_10153_12605_00911378000P?prdNo=2&blockNo=2&blockType=G2

And Greg, I know that it seems fishy; I honestly don’t know what the issue was. I’m as confused as all of you.

Tony, it was suggested while at Ric’s Ops Session that I send the unit to Dave Goodson first. Would you recommend that course of action?

I can confirm that multiple persons inspected my installation and confirmed that it should not be at fault. I’m wondering if the battery somehow supplies unlimited amperage if loaded? But if so, how do my Train Engineers handle it?

#16

Weird, but components can fail.

Batteries will supply current depending on the load (how much resistance)… they can deliver a lot if the resistance is very low, like a short.

Electrolytic capacitors can short if they get dented, or damaged.

Anyway, yes TOC would be a good idea… (TOC = Dave)

Regards, Greg

#17

Hhi Robbie.
Unfortunately I cannot hazard a guess as to what the problem might be without seeing it.
Ye, Ni Cd batteries will give unlimited current if shorted out. Until they self destruct of course.
If the system was protected by a suitable fuse in the battery circuit as instructed in RCS paperwork, the current would have been limited.

By all means send it to Dave Goodson but it will likely have to come back to me anyway. So perhaps sending it to me from the get go would be a good idea.