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Do faulty inline filters blow fuses?


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You make some good points but check your wiring rules and regs, just because it has a plug top doesnt neccesarily make it a portable appliance.

 

As far as I recalled it was, but happy to be corrected if that's not the case. I'm confident that pinball and arcade machines are though.

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As with all the dam wiring rules and regs and how they write them they can be open for interpretation and confusing. Your right in a business environment where public liability is of concern generally PAT testing is required but not by law as long as equipment is safe and maintained. However a pinball for example is one of those conundrums with the rules because of it's weight and dimensions it's an item that spends most of it's life sitting in one spot for a lengthy period of time, it has a plug but not really that portable, you require a trolley to move it , so in this sense it doesn't get moved around often. Same can be said with non fixed cooking appliances like free standing ovens that can have up to a 20A plugtops and upright fridges and freezers. They really aren't portable but have plugs. If your in the business of hiring machines out then yes I agree with you.
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I think we're talking about different things here. I was merely pointing out that AS3000 covers fixed wiring and AS3100 covers (plug-in) appliances.

 

As for test and tag (AS3760), it's only done as a business thing, not home use. The test interval for items that don't move (or specifically the cable doesn't move) only need to done every 5 years. Intervals for other situations are shorter, but not always easy to determine with certainty.

 

My comment about the earth continuity was a general one and something that anyone with a multimeter can do. It's not as good as doing a proper earth bond test (high test current), but a pretty good indication that the earth is intact. :)

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I have to say, the plug & cord, the fuse and the box with the filter is one area I now always check always on new machines. This was a result of a small tingle I received when leaning on the side rails of my TZ. Tracing from the plug I found the filter box (one in this post) the earth wire had been cut.
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I have to say, the plug & cord, the fuse and the box with the filter is one area I now always check always on new machines. This was a result of a small tingle I received when leaning on the side rails of my TZ. Tracing from the plug I found the filter box (one in this post) the earth wire had been cut.
Stops those pesky RCDs tripping. :\
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Stops those pesky RCDs tripping. :\

 

no it doesn't, nor should it ever. That's why RCD's have their place. As mentioned earlier in this thread, an RCD will trip at a set point of difference in active and neutral current sensing.

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@pocketmoney What does cutting the earth achieve then?

 

I would've thought if the machine was leaking to earth and that was causing a trip, cutting the earth would prevent that - until someone touched the live part that then completed the circuit with a zap.

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@pocketmoney What does cutting the earth achieve then?

 

I would've thought if the machine was leaking to earth and that was causing a trip, cutting the earth would prevent that - until someone touched the live part that then completed the circuit with a zap.

 

won't affect an RCD, earth leakage cutout it would. But as to why someone would cut the earth rather than fix the issue is something for the moron that cut it in the first place. Don't assume your machines are safe, the vast majority probably would be. You invest a lot of coin in these machines, so my initial point was if unsure, invest a little more in on going safety especially if you cannot do it yourself and please don't take short cuts.

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won't affect an RCD, earth leakage cutout it would.

 

Aren't they the same thing? From https://dnrme.qld.gov.au/business/mining/safety-and-health/alerts-and-bulletins/mines-safety/residual-current-devices-earth-leakage-circuit-breakers

RCDs used to be called ELCBs - earth leakage circuit breakers

 

Hmmm... Wiki says one triggers on voltage, the other on current? https://en.wikipedia.org/wiki/Earth_leakage_circuit_breaker

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An RCD is an earth leakage device effectively. The imbalance between active and neutral is almost always leakage to earth.

 

correct but if you are the "leakage" to earth an RCD will trigger, an earth leakage won't, unless you are touching mains earth. In either case an RCD if working properly will trip.

 

If you are wondering what the differences are between earth and mains earth then do some reading, essentially they are the same except the safety devices need a reference of "earth" to measure against so mains earth is monitored in the switch board). Earth being the ground you are standing on is roughly the same potential ( as long as your earth stake is good) as mains earth but is not monitored by the safety device. So earth leakage will not protect you if you go from mains to earth (what you are standing on), RCD will still see differential current from active to neutral and trip.

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Here is something to contemplate. Is it safer to have all the pinball's metal pieces connected to earth in the first place or disconnect every earth braid on the machine except the transformer body to the main's ground wire?.

 

While the factory idea of tieing every piece of metal or conductive material on the machine to ground is safe while it is all connected perfectly and in excellent condition, what about when the machine's ground lead itself fails?

 

Simply because all the metal parts are deliberately connected and the player's hands are on the metal side rails leaves the player susceptible to receiving an electric shock where as if none of the metal pieces were tied together, there is no chance the player would receive a shock even if something was to go tragically wrong inside the machine in the first place, correct?

 

A bit like the wife's hairdryer with no earth lead in the mains cable or the electric drill in the garage again with no earth lead. Fortunately both don't require an earth lead on account of both being in plastic non conductive housings so no need to connect the housing to earth but if you think about it, what in a pinball is ever likely to come in contact with the side rails, lockdown molding or coin door anyway that isn't low voltage?

 

If you ever thought of this, there is a reason all the metal on a pinball is connected.

 

It makes up a Fariday cage that prevents electrical emissions from leaving the machine and prevents emissions from other devices entering the electronics in the machine.

 

Sorry boys. We can't run pinballs without the earth leads all connected. Better to just maintain the existing earthing system.:realmad:

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Wow, are any of those still in use in Australia?

 

- - - Updated - - -

 

...there is a reason all the metal on a pinball is connected.

 

It makes up a Fariday cage that prevents electrical emissions from leaving the machine and prevents emissions from other devices entering the electronics in the machine.

 

While I agree that all external metal should be connected to the earth connection, it simply due to the safety aspect (and regulations).

 

I don't see a few bits of earthed metal acting as a Faraday cage. The best you could hope for is that earthing them stops them becoming mini antennas / reflectors for EMI.

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  • 2 months later...
They pretty much did away with the Thermistor later on. You can just cut it out and solder a wire in.

 

Just looking into this,

 

Don't you mean they did away with the Varistor?

 

WPC shows inline filter, Varistor & Thermistor.

http://arcarc.xmission.com/Pinball/PDF%20Pinball%20Misc/Williams%20WPC%20Schematic%20manual.pdf

 

WPC 95 shows inline filter (@ socket) and Thermistor.

http://arcarc.xmission.com/Pinball/PDF%20Pinball%20Misc/Williams%20WPC-95%20Schematics%20Manual.pdf

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You need the varistor, it protects against lightning spikes.

 

The thermistor, it protects against heat.

 

Exactly what heat you are supposed to get in the mains cable is beyond me.

 

Most thermistors if your machine actually had it factory fitted are long gone.

 

My advice, varistor is a must, thermistor not so.

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The "themistor" is an NTC (negative temperature coefficient) device use to reduce the surge current when turning the machine on. It may measure 5 to 20 Ohms when cold, dropping much lower as it heats up due to current being drawn through it.

 

The presence of an NTC is usually to reduce the peak current demand from the mains when the machine is switched on. This is important when you have a bunch of them all hanging off one circuit breaker. It can also reduce stresses on the power supply at the same time.

 

Removing the NTC will often have no ill effects on the machine, but it could cause issues (tripped breakers) in situations where they are all turned on via a master switch.

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Considering the majority of machines don't use them the long term effects seem negligible.

 

It looks like original WPC design used VARISTORS but WPC 95 onwards dropped the VARISTOR.

So surge current is reduced in all designs, But over voltage protection is dropped.

 

It may be a case of the introduction of switch mode power supplies vs older transformer supplies.

I don't know enough about pinball electronics history - So this is just a guess as to why newer designs may have dropped them.

Edited by ozfalcon
Clarify components in question
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