Grounding machines

[Lddrizzt]

Any one looking for those 3 prong computer cords could most likely get them for free. We all know someone who works on computers, ask them, they always have a few laying around. Go to your local school district, find the computer coordinator, and ask him, odds are he has a box of them gathering dust, in a closet somewhere. These are your best resources for these cords and most likely are there for the asking.

[napster]

Poor Luckydog...No tingles???? And with all the machines you have, not a single tingle???? I don't think your to old...I think you must be dead. :-)
There is nothing more exhilarating then getting out of the shower...And going into my garage with bare damp feet...Then reaching into the machines for tokens, only to get caught off guard with a refreshing tingle. NOT!

And yes, you would feel the tingle of a 100v machine over a 24v more. I have never looked to see what voltage my machines are. But I am sure I have a mixture of them. But even if you don't feel the tingle, it would be in your best interest to ground all of your machines.

[luckydog]

I got out of bed this morning, so I guess I'm still alive.

All my machines are on carpeting and i don't wear shoes in my home.

I guess I never am grounded????

[birdbrain]

lucky: you live in a mobile right? is it properly grounded? you may just be floating waiting for that REAL bad thing to happen when you happen to touch the trailer and the ground at the wrong time.added:really luckey make sure the frame and electrical panel are grounded it might not be on a older mobile.

[napster]

Yes Luckydog, carpets, socks, wood floors all provide adequate insulation from earth ground. Its mainly us members that have our game rooms in our garages and basements on bare floors that feel this tingle. We are located closer to true earth ground. All grounded receptacles in your house eventually end up connected to a grounding rod or cold water pipe at least 3 feet into the ground. This is true earth ground. If you think back some years ago (pre 60's) you will recall the days before GFI'S and insulated tools when you would read about people getting electrocuted to death while working outside with power tools. Especially if water was involved. Is was the fact that they were standing on ground that killed them. Less resistance means more current flow. Its the current (amps) that kills you, not the voltage. The average wall outlet has 15 to 20 amps. It only takes as little as 1/4 of a amp to kill you. Its the clothes, carpets, socks, upper floors etc. that help insulate you from true earth ground. This is why most people survive a electrical shock from our outlets in the house.
BOB

[monaghj]

Even on a two prong cord you should not be feeling voltage on your cabinet.

If you think about this ... its ok to have the chasis grounded. If you reverse the wires the machine is still going to operate (AC stands for alternating current and there is no polarity but there is a hot and a ground). However what should be a grounded chasis now carries voltage and when you touch it the electricity is using your body to go to ground.

The White Wire (neutral) and ground are supposed to be connected back to the same terminal block in your breaker panel. On a standard 3 prong outlet - the left prong is larger than the right. This is your neutral. So if you are wired correctly on a polorized outlet (left side longer than the right) the separate ground really is not necessary.

Here is how you can debug this quickly.

Step1: Check your meter.
Set your meter to 110v or 220v AC and using the two vertical prongs check to see that you have voltage. You won't believe the number of people who use a meter to check things out - do a ton of rewiring and then find out their meter is ka-put or one of the leads, or they used the wrong setting ** yada yada yada.... just check it.

Step2: Check for correctly wired outlet.
Use your Volt Meter (set to 110v or 220v AC) and check to see if the wiring of your outlet is correct. Simply insert one of the Volt meters leads into the left slot (longer) and one into the ground. You should NOT get any current reading whatsoever. If you do this means the outlet is wired wrong. Call an electrician.

Step3: Checking for ground.
Asuming step 1 went ok (if you got voltage don't bother to do this) then put one lead into the short (right) slot and one into ground. You should register 110v. If you don't get any voltage reading there is a good chance that the ground wire is not connected. If this is the case call an Electrician.

I doesnt matter if your house is 6mths old or 60 years old. It is possible that when your electrician was speed wiring or using an apprentice (translation: 1/2 drugged highschool drop out forced to go to trade school) that one of the wires on a daisy chained series of outlets got reversed. Also many of the outlets have quick connects on the back - if the wire is stressed it is possible that a gound is broken or just forgotten.

If all appears good with the outlet then check the wiring of the transformer. The line side of the transformer is not polorized and either wire can connect up to either lead.
If the ground wire on the cord is hanging loose it should be attached to something metal such as one of the transfomer mount screws or to a metal part of the machine such as the door hinge.

On the output side of the transformer - the output is still AC just at 24v now instead of the 110. These are marked hot and neutral. The neutral should also be grounded to the chasis. There is nothing to say that the doof who installed the transformer did it right. You don't need a electricans license to import Pachilos.

In a nut shell - the voltage on the chasis may be coming from a miswired outlet that is carrying 110v to the chasis through the line cord or it may be coming from the transformer output which is grounded to the chasis.

For those of you who have hooked up the extra ground wires to the outlet it is quite possible all you are doing is bleeding off the 24Vac from the chasis to a better ground than your body - in all likely hood if this fix worked for you your transformer is not wired right.

[arbycoffee]

wowie very good explaination

[logicprobe]

On the output side of the transformer - the output is still AC just at 24v now instead of the 110. These are marked hot and neutral. The neutral should also be grounded to the chasis. There is nothing to say that the doof who installed the transformer did it right. You don't need a electricans license to import Pachilos.

In a nut shell - the voltage on the chasis may be coming from a miswired outlet that is carrying 110v to the chasis through the line cord or it may be coming from the transformer output which is grounded to the chasis.

For those of you who have hooked up the extra ground wires to the outlet it is quite possible all you are doing is bleeding off the 24Vac from the chasis to a better ground than your body - in all likely hood if this fix worked for you your transformer is not wired right.

Jay... you're saying that one side of the transformer output should be connected to the chassis????

[monaghj]

Thats not quite what I am saying...I would not go adding wires directly off the transformer if one does not exist.

One side of the tranfomer output is Neutral - which may or may not be tied to your chasis. If you are feeling voltage something is tied to your chasis and it isn't a ground.

You can check this by putting your meter (set to 24/50 ac) on the outputs of the transformer (NOT THE INPUT !! as we are using lower meter setting) and confirm power .

Next take 1 lead and touch the top of the transfomers metal frame and put the other on one of the transfomers output - note the meter reading. Then move the lead over to the other transformer output. One combination will show power, one won't.

The lead in which you got power from is HOT. The other combination won't show you power. This is Neutral.

Neutral is what should be tied to the chasis. This chasis ground may either be directly off the transformer or it may occur through some other part of the machine. I maintain there should never be voltage on the chasis but I would not go adding wires directly off the transformer if one does not exist.

The next test is to use your meter between the neutral lead off the transfomer and the chasis. IF you get voltage then your transformer output is wired backwards.

Reversing this should cause the voltage to go away.

[Lddrizzt]

Okay I am not super knowledgeable when it comes to electronics, but when it comes to electricity, I feel I know a little more.
Jay, you are saying that the neutral coming off the transformer should tie into the chassis...[QUOTE=Jay]Neutral is what should be tied to the chasis.[/QIOTE].
I have to disagree, by the power of common sense then the chassis just became part of that alternating current. ZAP pause ZAP pause ZAP need I go on? The neutral off the transformer needs to be tied to the rest of the machine's wiring NOT THE CASE. What are you thinking?

PEOPLE DO NOT DO THIS DO NOT GROUND YOUR TRANSFORMER TO THE CASE IT WILL HURT TRUST ME!

[monaghj]

I agree with your statement.

I have explicity said DO NOT connect any wires from your transformer anywhere.

What I have said is that if you are feeling a current on the outside of your chasis it is not getting a decent ground and perhaps quite the opposite - it is receiving a feed from the hot line.

The fix for this is to reverse the wires on the output of your transfomer. NOT to hook up any thing from the transfomer to ground or otherwise.

[logicprobe]

The fix for this is to reverse the wires on the output of your transfomer. NOT to hook up any thing from the transfomer to ground or otherwise.

Now I'm really confused.
On one hand you said that the output of a transformer has a neutral and a hot... and that the neutral should be connected to chassis. In fact, you've said they would be marked this way on the output (secondary).
I'm looking at a PowerVolt 24V 6A transformer (common for pachis) right here in front of me. I see no markings. And an ohmmeter shows no continuity between any wire... primary OR secondary... to the core. If there WAS, there would be an internal short! And seeing as how these are usually mounted on the wood cabinet in the first place, the core isn't even touching the chassis.

Are you thinking that these pachislo transformers are autotransformers... with a single tapped winding? They aren't!!!

They are two separate and isolated windings on a common isolated iron core... a basic power transformer. Reversing the plug does nothing to place the house current's hot or neutral on the chassis of the machine... the chassis isn't connected to either one! NOR is the OUTPUT of the transformer connected to the chassis. NOR SHOULD THEY BE!

How would reversing the wires on the secondary of this transformer (which is... and SHOULD be floating) change any kind of ground connection?

Folks... if you look carefully inside these machines, you'll probably see a green wire that has been simply cut off when the machine left the parlor, and left hanging when the importer installed a transformer. In the machines that have the 100V power supplies, there will probably be one of these green wires, too. This green wire was connected to a ground at the parlor... for safety. If that green wire isn't there, then maybe the importer removed it for some reason, but that's rare.

In the simplist fix for this problem... do as the Japanese parlors do... and connect that to ground.

As we've shown toward the beginning of that thread, and proved here and other threads before... that will take care of your problem.

[monaghj]

No - what I am saying is that if you have a mild electric charge on your chasis it is likely because either the transformer is connected to your chasis or some "live" component may be connected to your chasis. The shock can only come from the hot feed.

The Neutral wire - (white) does not carry a current on it. The Green Ground does not carry a current on it either. If you were to open up your breaker panel you will see that the two are in fact connected together to the same bar and then that bar connects to a large ground wire that goes deep below your house.

If the white wire happend to connect to your chasis you would feel no shock - only the black hot can do that.

If you reverse the output of your transfomer the shock will likely go away because the hot will no longer be making the connection to your chasis.

[napster]

Well this topic is getting beat to death. Once again I agree with logicprobe. The transformers should never be connected to the chassis. I also never recall markings on any transformers that indicate one wire from another, either on the primary or secondary windings. I have never looked inside to see what the transformers looked like...but now that logicprobe described one, its clear that its just a single winding output with no center tap. These secondary windings should go directly to the low voltage section to convert the AC to DC via a bridge rectifier. If the transformer was accidentally connected to the chassis...I see two possible scenarios. First, when we go to ground our machines we would also be grounding the transformer, and it should overload and either pop a fuse or the internal breaker if it has one. Second, I believe that the chassis is connected to the DC ground, which in this case would toast the machine. AC entering DC components would burn them all out in a nano second. The voltage that we are feeling is very minute. The small tingles are only noticable while lightly brushing up to the machine. We are not feeling full blown out shocks. Most times we don't even notice the tingles. What I need to do this weekend is to grab my meter and go inside to see what makes this thing tick. I don't think the Japanese have found a way to re-write Ohm's law. I will post any results that I may find...But as of now I still say that grounding the machine is the answer.
BOB

[birdbrain]

you've never been knocked off a ladder by completeing the circuit on a neutral?

[pachitom]

After reading the above posts I thought I would put my two tokens worth in.

Most general purpose stepdown transformers are like Logicprobe stated, both the primary and secondary windings are isolated from each other and from the frame of the transformer and polarity in these applications does not matter. (There is a polarity that must be observed if connecting more than one winding together on transformers with multiple windings. But this is different than a HOT or Neutral and is not of concern here).

Monaghj is correct that there should NOT be a current on the green ground wire. BUT there is a current on the Black and White wire, the amount of current on the white wire is the same as the current on the black wire unless there is a small amount of current going to ground elsewhere such at through your body if you touch a hot wire (OUCH). That is the basic principal of a ground fault breaker, the amount of current through the black wire is compared to the amount of current through the white and if the currents are not the same the breaker will trip.

[cwstnsko]

A lot of what you guys are saying is valid in realtion to US electrical practices and US market configured appliances. These machines are designed to operate in the Japanese electrical environment which operates a little differently than ours. In Japan, the two prong cords are NOT polarized! Neither wire on the power cord is designated hot or neutral. If your pachislo has a polarized plug, it is probably because an American transformer has been added. Regardless of the cord style, the machines are designed to be externally grounded through the use of a seperate ground wire in the parlors. The machines come from Japan with the ground wire intact and the refurbisher removes the ground wire as part of their prep, since most Amercian consumers will be confused if the ground wire is left hanging from the machine.

I believe someone posted a diagram / explaination several months ago that expalined why it would be common in a US installation for a 100V machine to measure roughly 60 VAC on the chassis, since the chassis, if not grounded with a ground wire would tend to float to a voltage halfway between the two legs of the AC input. 24V machines with transformers only tend to float to 12V which most people will not feel. In either case, it is generally accepted that the voltage is not really dangerous, since there is no meaningful current flow required to dissipate the voltage. Probably less current flow than a static shock, and certainly far less voltage.

If you were to replace your power cord with a polarized plug, and you could guarantee that your machines could NEVER be plugged in to an improperly wired outlet, then electrically speaking, you could use the neutral wire to ground the chassis. Personally I would never do this since plugging said machine into an improperly wired outlet could easily kill you.

FYI, When we bought our NEW house last year that had just passed electrical inspection, we had over 10 outlets wired backwards, which at the same time defeated the GFCI protection for those circuits. I caught the mistakes during my final inspection prior to closing. Don't assume that anything is wired correctly unless you have verified it yourself.

[gwarzin]

FYI, When we bought our NEW house last year that had just passed electrical inspection, we had over 10 outlets wired backwards, which at the same time defeated the GFCI protection for those circuits. I caught the mistakes during my final inspection prior to closing. Don't assume that anything is wired correctly unless you have verified it yourself.

You really do have to test all outlets for yourself. When we bought a new house one of the outlets had 110v on the ground! The drywallers had driven a nail through the wiring!

[luckydog]

I worked for a print shop up north, they had 30 presses wired by 4 different electricians. everyone wired them differently,

It made things more intresting when working on them!!!!!

Some 110 outlets were wired to 220.

ever tried plugging a vacumn cleaner into 220. it didn't run for long

[photos8484]

Referring to the above postings by gwarzin & cwstnsko, it is worth it to go out and buy one of the plugs I mentioned earlier. I'm sorry, I forget what they're called, but they look like a large 3 prong male plug with leds or lights at the rear. You plug it in to each outlet & by the color of the lights that glow, you can tell whether or not that outlet was wired properly. You would be surprised by the number of outlets in your home that are incorrectly wired, as opposed to those which are wired correctly. They're not very expensive & hardware stores generally have them, probably also Lowes, too. There are models for standard outlets & there are some for, I believe, GFCI outlets.
Very cheap insurance, indeed!