why does my makita go pop occasionally ?

[SillyOldDufferModerator @sillyoldduffer]

Posted by Kiwi Bloke on 26/01/2020 10:05:01:

I'm pretty sure that the 'yellow thing' is a mains suppressor, comprising three capacitors in a network, and it's certainly the culprit. …

Me too. VDE 565.1 is a quality mark covering interference suppression devices.

I don't recognise the seem or feem trademark, so I guess the suppressor was made in the distant past. 25/065/04 is the climatic code (Can't find a decode table but it covers the suppressor's normal operating condition: arctic, tropical, temperate etc.) That the suppressor doesn't carry any of the modern codes such as EN60384, or UL1414, or GBT/T14472 also suggests it's at least 15 years old. Time for a new one! Provided it will fit in the available space, almost any UK mains rated Y suppressor will do. As it only costs a couple of quid, Bear's find is surely worth a punt.

Dave

[Anonymous]

It would seem odd to have Y-capacitor suppressors when there's no earth connection?

Andrew

[gerry maddenParticipant @gerrymadden53711]

KB thanks for excellent and informative info and to SoD for confirmation. I'm on the case now following Grizzlys suggestion.

Its satisfying to keep these old machines going using skills knowledge experience and of course the internet.

Regards,

Gerry

[Grizzly bearParticipant @grizzlybear]

Hi Gerry,

Regarding the 'search' duckduckgo, "Makita mains noise suppressor."

It gives you some insight to suppressors in general.

Interesting comment from Andrew, regarding earth (Ground) connection.

Good luck!

Bear……..

[SillyOldDufferModerator @sillyoldduffer]

Posted by gerry madden on 25/01/2020 19:04:11:

… As a single lead it cant be a temperature sensor. So any ideas ?

Earth connection to the motor, done that way to speed assembly? I'd prefer a nice bolt!

As far as I can see the yellow thing has 3 wires, which I'd expect to be L, N and E on a simple suppressor. It's not a filter. Inside, capacitor across L and N, capacitor from L to E and another from N to E, the whole lot wrapped in silver foil as a screen which is also connected to E.

Dave

[Kiwi BlokeParticipant @kiwibloke62605]

'Its satisfying to keep these old machines going using skills knowledge experience and of course the internet.'

Absolutely! Save the planet! Join the Right to Repair movement!

Just to tie up a few loose ends about these things, for anyone who's interested…

These three-leg capacitor networks comprise one X-class capacitor connected L-N and two, equal-value, Y-class capacitors, one L-E, t'other N-E, hence the 'delta' moniker. X-class caps are designed to fail by going short-circuit. This should blow the supply fuse or breaker, alerting one to the fault and rendering the device 'safe' – i.e. unpowered. Y-class caps should fail open-circuit. If failure were by short-circuit, the frame of the device would be connected to the mains live or neutral – not desirable.

I've looked in a couple of catalogues and am surprised to see many such devices are of metallized paper construction. Given my experience with this construction failing, I'm surprised. However, dredging through the memory banks, I think the failures were all of the same make, so perhaps metallised paper per se is OK, but 'my' caps' manufacturer was the culprit. I note that above I've said '…designed to fail…': I wonder…

[Anonymous]

Posted by Kiwi Bloke on 26/01/2020 20:59:51:

X-class caps are designed to fail by going short-circuit. This should blow the supply fuse or breaker, alerting one to the fault and rendering the device 'safe' – i.e. unpowered.

Possibly less stringent testing for the requirement to fail open, but it would seem unlikely to design for failure to be a short. What happens if the shorted capacitor doesn't blow the fuse? You burn to death rather than get a shock.

Andrew

[Kiwi BlokeParticipant @kiwibloke62605]

OK, perhaps it's more correct to say that X-class caps are allowed to fail short, whereas Y-class must not and are designed accordingly. The message is that one should choose the correct class of cap if replacing caps connected to the mains, i.e. X-class between Live and Neutral and Y-class between Earth and either Live or Neutral. Be careful!

[gerry maddenParticipant @gerrymadden53711]

As per Grizzly's suggestion, a new capacitor was obtained fitted and all is well. Checked the old one. No leakage on the Ohmeter but a physical stripdown confirmed damage.

Thanks all for your inputs.

Gerry

[OldironParticipant @oldiron]

Glad you got a solution to the problem Gerry.

regards

[Author]

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