24V issues in coin box?? Need help.

[PaulLovesJamie]

Apparently I have issue(s) in my coin box(Es), I need some help. Any suggestions what else I might look at would be greatly appreciated.

Over the last 2 years I've had a coinco vantage bill acceptor (bay5) out for repair 6 times. Symptoms varied - "send out for service", not accepting bills, and for the last 3 times the stacker was cycling. Coinco says the unit is fine.
Last month I had multiple electronics failures in bays 4 & 5: both timers (EV quick pay) failed (display went blank), and both vantage bill acceptors the stacker was cycling non stop. These did not all happen at the same time, they occurred separately over a period of about 10-14 days.
For one of the EV timers I was there when it happened - the timer went blank when a customer switched from PS to HP Soap.
Weather was good the whole time - highs around 85-90, no storms.
At the moment I have dixmor LED7's installed in these bays (CC & validators disconnected); no issues whatsoever for the past 3 weeks.
No problems in any of the other 3 bays.

Coinco has the 2 vantages, they say they both work perfectly, no suggestions (so far?) as to what my problem(s) might be.
EV repaired both timers - replaced the 5A fuse and the TVS diode, but I dont know if they were actually bad or if they replace them as a matter of course. They said I need to install a fuse. iirc one of the EV timers was out for repair once before, about a year ago.


Background on my setup:
I have a separate transformer on every bay, 100VA.
Voltage measures at 26 - 27 VAC, no variation for the last 20 years afaik.
Transformers are wired on phases A&B, 120V, not the high leg.
Transformers have a 7A slow blow fuse.
Transformers are grounded.
Coin boxes are grounded.
Power supply to the coin boxes is grounded back to the breaker box.


What I've done so far:
Power company:
confirmed that there are no known/reported issues on my line, no construction, no outages, no brownouts, nothing.
visually inspected transformer
recorded voltage for 10 days - looks perfect.

I checked the connections on every breaker and grounding wire in the box, all are tight.
I checked every connection on the 24V wires to & in my coin boxes, cant find any loose connections.
I tested for amperage in the grounding rod - zero.

I've ordered 24V snubbers (IDX), I will install them as soon as they arrive.
I plan to put smaller fuses on the 24V transformers - probably start with 4A and see how low I can go by trial & error. (Incidentally, does anybody happen to know the power requirements of the EV timers?)
I'm considering installing a whole service TVSS, but hesitate to spend the $ without knowing if it will solve any problems.

Suggestions on what to look at would be greatly appreciated, thanks.

 

[Greg Pack]

No idea, but until I figured it out I would fuse the timed output with a fast acting fuse 1 amp smaller than the rated load, and maybe try a new rotary switch.

 

[2Biz]

Do you have the "Commons" tied together on all the bay transformers? Just throwing this out there in case there are phasing issues that might be causing problems, especially since you are running sensitive electronics...I have all my commons tied together without any issues, but I'm only running LED 7's and I made sure all my Transformers were phased alike...Sounds like you've covered all the other "Basics".

BTW, I have 4 amp fuses on my 75KVA transformers. It doesn't sound like you're over doing it with the 7a...But you might also incorporate cfcw's advice. It won't hurt...

 

[Eric H]

For one of the EV timers I was there when it happened - the timer went blank when a customer switched from PS to HP Soap.

I've had this happen in the past. It turned out to be a bad rotary switch. Unfortunately, this may not account for your other problems.

 

[cmawash]

may be floating grounds, check for voltage differences between grounds of each system, recommend slow blow 4 amp fuses, 7 amp improper size for 100 va transformer, coin co vantage units in our view are junk units( nothing but trouble) , check cable runs 24 volt power needs current to meet power needs, mods over the years may be over taxing the system. may consider new control wire.

 

[cmawash]

thought about your problem, trying ungrounding meter looks like your using 220, may be a problem with ground loops isolate each bay electrical system by eliminating ground wires and see how system operateds

 

[mjwalsh]

Paul,

We have had the Coinco Vantages wired in parallel with MicroCoin QLs & Dixmor LED7s for about 3 years now. We also have GinSan distribution boards that allow us to have momentary switches & leds showing the customer the actual choice of selection that is current. Unless the Coinco Vantages are not compatible with something else in your system ... I doubt it if they are the problem. I did have to send them in a few times but it is was related to the exasperating huge numbers of $1 bills vs much fewer $5,$10s & even $20s. The high number was based on the specific error code light. Knowing the resiliency of my customers ... I know that the high number of $1s is much better in the form of dollar coins in the more durable MicroCoin QLs.

It does sound like some unexplained noise ... I currently have that intermittent grief on 2 of our 16 electronically controlled laundromat dryers so I can definitely relate. An electronic engineer advised me to make sure that there is less than 1 ohm from the ground on the main panel to the ground on the coin box controls for starters.

Check to make sure there is the 24 VAC between a lead on the low voltage side of your transformer & ground. If it is 12 VAC that means the neutrals & grounds are not properly bonded together ... causing the potential floating voltage problems that cmawash referred to.

If I was in your area ... I would come over free of charge ... with my Fluke 771 checking for stray thousandths of milliamps. BTW we & other operators are or should be very much interested in the outcome of your dilemma for the sake of understanding goofy problematic electronic noise &/or goofy electronic hardware compatibility issues etc.

mike walsh http://kingkoin.com/USA_Deficit_Reduction.html

 

[PaulLovesJamie]

Thanks for the responses so far .

Switches:
The 2 bays having problems both have the larger rotary Electroswitch (link), my other 3 bays have the more traditional smaller rotary electroswitches. Both were installed new 2 1/2 years ago along with brand new etowah coin boxes with the quick pay timer, CC, and bill acceptors.
Since my issues with these 2 bays have been regular but spaced out over 2 years (until a few weeks ago), I'm inclined to think the switches are not the problem.
Good suggestion though, I'm not ruling it out. Tough to test without replacing the switch and waiting to see if the bill acceptor or timer fries though... not sure how else to test what appears to be an intermittent problem.

Smaller fuse
Agreed, smaller fuse. This wont solve the root cause, but might help protect equipment and might help isolate where the problem is. In fact maybe I should put a separate in-line fuse on each individual electronic device, interesting to see if something is drawing a larger than expected load.

Consider new control wire
Problems are occurring in 2 bays, so hopefully this is not my root cause. Good suggestion though, perhaps an abraded wire is causing issues.

...make sure that there is less than 1 ohm from the ground on the main panel to the ground on the coin box controls for starters.
Check to make sure there is the 24 VAC between a lead on the low voltage side of your transformer & ground. If it is 12 VAC that means the neutrals & grounds are not properly bonded together ... causing the potential floating voltage problems that cmawash referred to.

I think my grounds are good - tested them when I installed the new coin boxes 2 years ago, but will check them again.

27VAC every time I've ever checked it for the last 20 years, including this month. I also checked it in the bay, same 27VAC.

 

[PaulLovesJamie]

Commons tied together? Floating Ground?
I do more electrical work than I should; I know just enough to be dangerous, so here it comes... I dont know.

My transformers are fed by 2 hot wires, phase A & B, so afaik I'm running it as a 240 to 24 V transformer.
On the 24V side, I do have a wire that goes straight to the grounding lug, and I also have a common wire on the same terminal that goes to the bay. Since all common wires eventually go to a grounding lug, doesn't that mean all commons are in fact tied together??

thought about your problem, trying ungrounding meter looks like your using 220, may be a problem with ground loops isolate each bay electrical system by eliminating ground wires and see how system operateds

cmawash, I'm not sure I understand.
Are you saying that since I'm transforming from 220 I can simply disconnect the ground wire(s) on the 24V side of the transformer?


Would I be better off (safer?) changing the way my transformers are wired to use one 120 and a common instead of the 2 120's?
Is that what most of you guys do?

FYI, the transformers were wired this way when I bought the wash 20 years ago, it has never occurred to me to change them.

 

[PaulLovesJamie]

thought about your problem, trying ungrounding meter looks like your using 220, may be a problem with ground loops isolate each bay electrical system by eliminating ground wires and see how system operateds

Also - the etowah valley timer manual is emphatic about having both the door and the timer wiring grounded to common, so I think this is not an option?
Unless I misunderstand that, this supports my thinking that I should rewire my transformer to 120+common. I think.

 

[PaulLovesJamie]

here's a pic of a bay transformer, in case thats helpful.

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[PaulLovesJamie]

And in case anybody is interested, here is one page of the voltage recording results.
They recorded phases A, B, & C (high leg) for 3 days & checked the results. Then they reinstalled the recorder for another week. I can put up all 6 pages if anybody is interested, but they all look basically the same - except the high leg, which of course varies between 212 and 222 volts.

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[MEP001]

Despite what mjwalsh said, you're not going to see 24V if you take a reading from the transformer to the ground because your transformers are wired at 220. EACH OUTPUT from the transformer will read 12VAC to ground. He's wrong that reading 12V indicates a problem.

If you haven't done this already, check across two transformers on the same output of each one, and you should read 0V, and do the same with both output terminals (for example X1 on bay 1 and x1 on bay 2). If you can go across all the bays and all the terminals that way and see no voltage, everything is "in phase." If they aren't, and if all the "common" sides of all the transformers are interconnected somewhere it's neutralizing the voltage when two bays with inverse wiring are switched to the same function at the same time. The fix is as simple as making sure the same leg of 120VAC is on the same side on each transformer.

 

[Eric H]

I feel like I deal with transformers so rarely I need to relearn everything every time, but...it looks like primary 3 and 2 are supposed to be jumped together for 240VAC?

 

[PaulLovesJamie]

I feel like I deal with transformers so rarely I need to relearn everything every time, but...it looks like primary 3 and 2 are supposed to be jumped together for 240VAC?

Correct, any yes they are jumped together - just really hard to see in the pic because the flat metal that jumps them is painted black.

 

[PaulLovesJamie]

If you haven't done this already, check across two transformers on the same output of each one, and you should read 0V, and do the same with both output terminals (for example X1 on bay 1 and x1 on bay 2). If you can go across all the bays and all the terminals that way and see no voltage, everything is "in phase." If they aren't, and if all the "common" sides of all the transformers are interconnected somewhere it's neutralizing the voltage when two bays with inverse wiring are switched to the same function at the same time. The fix is as simple as making sure the same leg of 120VAC is on the same side on each transformer.

Very helpful explanation, thanks.
Cant get to the wash until tonight, will check this when I get there.

 

[mjwalsh]

Correct, any yes they are jumped together - just really hard to see in the pic because the flat metal that jumps them is painted black.

Paul,

Based on your picture ... your 240 VAC to 24 VAC transformer is the exact same brand & model that we have for each of our 6 bays. It appears to be wired the same as Specialty did at their factory for us ... which I believe is the preferred way which will cause the preferred increase from 12 VAC to 24 VAC when testing to the bonded neutral-ground. I believe that is what you earlier verified. We also have 240 VAC three phase with a wild leg as our feed from our local power company. I think it was smart for you to have an engineer from your power company verify that there are not intermittent unacceptable fluctuations of voltage within a phase coming in at your meter - main panel.

mike walsh www.kingkoin.com

 

[MEP001]

It appears to be wired the same as Specialty did at their factory for us ... which I believe is the preferred way which will cause the preferred increase from 12 VAC to 24 VAC when testing to the bonded neutral-ground.

That's not how it works. Either the transformers are wired 240V and each output leg is a 12VAC output with a floating common that should not be grounded, or they're wired 120V and there is a 24VAC output and a neutral that can be grounded.

 

[2Biz]

My transformers are wired from (2) 120v legs of the wild leg 3 phase. You don't use the center leg of the 3 phase because its 208v...Or mine is anyway! My transformer commons are not grounded. I have all my output commons tied together to make it easier to wire the kip solenoids. Its much easier to take one common and jumper to each solenoid on the manifold. Saves wiring! But to do that, you have to have all transformer "Phased" and commons tied together...

So in essence, if you have all output commons grounded to the same metal surface/panel, then yes your commons are tied together. But like Mep suggests, I really don't know if you should be grounding your commons?

 

[2Biz]

Ok..So now even I'm a little confused. I was curious so I went to the wash and checked each of my 4 transformers.

Inputs = 243v
Outputs = 26.7v
All commons checked to ground = 11.7v

All hots checked to ground - this one I'm having issues with, mentally!
Bays 1 & 3 = 15v
Bays 2 & 4 = 26v

Its been set up this way for 30 years. I tied the commons together 3 years ago when installing equipment that had a single common input for all 4 bays. Trifoam and SFR...So the only way it would work was if I tied the commons together. At this point, I wonder if it matters how its wired as long as you have 26v across the outputs and have a common path back to the transformer. What I have works but is now confusing me....