Solenoid connectivity

[treefrog]

I try to avoid electric stuff, especially when dealing with 240v direct feed around your machine. Having got a Dropacopper going earlier in the week, I decided to tackle another electric machine an Allwin this time. It similarly uses micro switches to trigger the solenoid from the ball passing the relevant win hole. I did not know if it mattered which way 'round the wire went for the solenoid, so tried based on how the Dropacopper was set-up, but when testing both large 1amp fuses blew on the Live and Neutral cables. I can only assume switching the cables to the solenoid unless it is another fault of course... Anyone know, would be appreciated....

I had to replace the solenoid as it was missing and happened to have a heavy duty type rated 240v seen attached to the machine. The other one was a broken one from another machine.

[badpenny]

It's hard to see the plate marked R.A. Webber but it looks to me as if it's rated at 4 amp.

If that's the case Tom, it's no wonder your 1 amp fuse is blowing.

If it is my eyes that are short circuiting then it might be worth testing the coil on the solenoid for continuity. If it's an old one then the insulation on the copper coil may have worn and the current is shorting out to the frame, which would also blow the fuse.

Have you a continuity meter or tester, if not they are easy to make.


Jeremy

[treefrog]

Yes I get continuity through the solenoid and your right all 3 solenoids state rat 4 on them, but the fuses that were already in this machine were 1amp and the Dropacopper I got going has a 5amp on neutral and 2amp on live. One of the solenoids pictures above is blown and I had to replace as no continuity. So I can ramp up the fuses (blooming pain as they are big 30mm ones) or would wiring the wrong way round affect this. I had tested the fuses before blowing and both were good.

[JC]

Not withstanding the appalling title of this thread and its made-up word , the solenoid coil can be connected either way - makes no difference. As BP says, the rating plate on the coil is not focused well enough, but if it does state 4 amps, that's a hell of a lot of juicy stuff at 240v. That's 1kw.........you could knock a couple of pylons over with that. Are you sure it needs to be that big?

[treefrog]

I told you I was a simpleton when it comes to wires and their definition you wonder why I am even touching these things, but yes it has a 4 in the box stating rat, so assume rat is amp rating not watts. Wonders seemed to use this size on their machines, I guess getting the slides back maybe needs a bit of effort.

So if not due to which way round the coil is wired, then likely to be fuse rating unless of course there is another fault....I will order some 4 amp fuses (fast blow) and cross fingers. It is difficult getting these units as replacements as most I see tend to be reduce voltage, usually 50v.

Always a but scary so many of these machines of the period with 240 vaults in the back.....

[JC]

I will order some 4 amp fuses (fast blow)

No, go for slo-blow - when the solenoid kicks-in, there will be a current surge, which may be quite significant. Maybe the 4 amp rating is the maximum surge - still sounds pretty hefty to me.

[JC]

By the way.....

240 vaults in the back.....

vaults?

[brigham]

It won't take 4 Amps at mains voltage.
That figure probably refers to whatever it was designed to do, before it got used in a slot machine.

[treefrog]

I am wondering if I have another faulty coil, as the other thing I failed to mention was that the old fuse connector box, when engaging one of the trips, a small flash did happen and one of the connector terminals broke away. It could be I guess this was also a fault.

I compared a working coil and the suspect one for continuity across the two leads and both good. I tested resistance at 200ohm for both units and they both came out as 0.....I read somewhere this should be above 2, but again maybe my ignorance and not proving anything. Going to have to await more fuses anyway, but would the tests performed above prove a good or bad coil Also checking all cables and terminations for shorts etc. It is earthed all over the place.

[gameswat]

There are usually only two types of coil failure:
1) the wire has broken, there will be no circuit and no way of blowing a fuse. If you can find the break and resolder then fixed.
2) the coil has overheated for some reason cooking the lacquer coating on the wire and causing the windings to start fusing together, this will decrease the amount of windings but will still test as a continuous circuit, eventually when it's shorted out enough of the windings it will blow fuses.

[radiochrissie]

Gameswat is spot on. The reason you're blowing fuses is because the coil/coils have got shorted turns due to overheating. The fact you have different rated fuses in the live and neutral means someone has put the wrong fuses in. They should both be the same rating.
I would suggest powering up each coil separately with an inline current meter (not voltage) to find the culprit. Do you have a circuit diagram for this?

[treefrog]

Well as suggested by linginthepast, I decided to have a go rewinding the coil and ordered some 29awg coated wire and started the laborious task in counting coils and measuring the length of the existing wire. While doing so found a few breaks early on, probable cause of the issue and the wiring coating was very brittle and disintegrating.

While awaiting the new wire I went through piles of old spares I have, old reduction motors etc and found a few were similar size and observed 240v on the plastic spool. Checked continuity on one and took apart, tried in my machine, it only works......it turns out I have loads of spare coils.... So another working machine

No idea what all these reduction motors are for I have, there are boxes of them...

By the way on the fuse front, I bought loads of different sizes of slow and fast burn and started with 1amp fast burn, which work fine, so reckon these would be safest.

[badpenny]

I think your geared motors are German, NSM, Wall machines like Rotomat or those roulette ones that spin a large ball bearing in a vertical plane.

[treefrog]

Could have been, but most are British like Carters from Romford which is what I used, Mycalex from Cirencester and Brevel.....

Also JC was absolutely right about slow burn fuses being more appropriate, as blown two fast burn 1amp fuses after a few goes. With slow burn 1amp in now, no problems after many runs

[treefrog]

Ok, now onto the Jamieson’s machines and partially got an Electrodart working bar a few bulbs and a payout issue. Went through the wonderful guides in the resources as I never realised the numbers move one place forward after a win, I thought I was going mad. Anyway bell rings on a winner and I hear a slight noise from possibly the solenoid, but no movement. Looking at it, the thing looked burnt out will lumps of coating crumbling off and I tested continuity which was dead, so assumed this had failed.

So was going to take one from another machine as I am trying to make 3 or 4 good machines out of 5..... but I tested that one and again no continuity, tried another two and the same. I had thought there should be continuity on all coils and cannot believe I have 4 failed units. Resistance is around 0.13ohm and read somewhere this should be below 0.3. Also the continuity setting instead of a beep I see a reading around 170 whatever that means.

Electrically inept.....Help

Black one is the one I thought had failed and the other a spare...

[brigham]

I'd be delighted to follow your progress on the Jamieson's machines. I got my BINGOLA working using the resources section hereon; prior to this, I was under the impression that it was somehow random!
The later types (with the rotary selector made of BA size bolts) are much simpler, you can work them out without GPO training. My next one will be a ROTOLITE, so I'll be watching carefully!

[JC]

I see a reading around 170 whatever that means.

Tom, are you sure you should be doing this?
I assume, depending on what range you have your meter set on, that's 170 ohms. At 240v, that's about 1.4 amps, so I might expect a slightly higher resistance.
Where did you get 0.3 from? That's more or less a dead short - at 240v, the coil would draw 800 amps, which is very nearly 200kw!

[gameswat]

Mr Frog, I would guess that much of your coil breakage issue relates to the high power and action of those solenoids, basically the hard hammering of the plunger and stop creates a mini earthquake every time and those delicate copper wires don't like it at all! Can't tell you how many pinball coils (especially flipper) I've partly unwound to find the break and solder back together to repair. And most E/M coils are in the weak 24 -30 volt range, so when you get to 240 volt coils they are scarily powerful in comparison. I guess the only other thought I have is where did your faulty coil collection come from, pieced together by you from different sources or all from the same place? Because they could have already been removed by an operator due to failure and never discarded?

[treefrog]

So JC, the 170 Reading I was getting was on the continuity setting on the multimeter, no idea what it means, but when I get continuity on anything, this will normally show 0....

Gameswat, these coils are all from Jamieson’s machines and each machine bought from separate source. They are not 240 like the earlier wonders machines in the thread, I am guessing maybe 24v, but probably stated in one of the guides on the resource section.

Odd really......if they have all really failed I am going to be doing a lot of winding, unless I am missing something.....

[JC]

OK, let's see if I can help with some general understanding. The 170 reading will be ohms. You say you'd normally expect 0 when testing for continuity, and that's quite correct - there should be no resistance when testing for absolute continuity. However, you're testing a solenoid coil, in which there must be a resistance otherwise it wouldn't work. I've no idea whether or not 170 ohms is correct, but if the coil is operating at 24v as you suggest, the current would be 0.14 amps, or 140mA, which seems a bit low to me - I would expect a solenoid to draw more current.
In general, you need to have a basic understanding of the relationship between voltage, current and resistance, which is known as Ohm's law. The formula to remember is this:

V = I x R

where V is voltage in volts, I is current in amps and R is resistance in ohms.
The formula can also be expressed as:

I = V/R

and

R = V/I

I've no idea what sort of current a payout solenoid would draw in a Jamiesons machine, as I've never had to replace one, but I guess somewhere in the region of 1 to 2 amps, in which case you could expect a resistance of 12 to 25 ohms. But this is very much a guess - I really don't know! As a rule, the more powerful the solenoid, the more current it will draw, at a constant voltage.

I hope some of this will help, but do try to get an understanding of the relationship between V, I and R.

Jerry