what is this elecrical component.

[tim_ber]

Neighbour knows I can sometimes fix things...

So he has given me his extractor fan to look at. Looks new.

Electricity is getting to circuit board and leaving circuit board. Electricity applied directly to motor does nothing, so I started to look at the motor.

This component has the blue neutral wire from the circuit board going to it, but there is no continuity across the component and if I try to measure its resistance I get no result. EDIT - I HAVE NOW FOUND OUT IT IS A microtemp cutoff fuse.

http://cpc.farnell.com/thermodisc/g4a01128c/fuse-thermal-w-e-128c/dp/FF01026

How do I test it, what does it do? I'm guessing that at above 128 degrees C, it shuts the motor down. Is that right?

But, should I just buy another one and replace it? Good practice with fuses is that I should know what made it 'blow'.

Anyway,
(1)should I get continuity across it? If so then I know it has failed.
(2)Should I just replace it and test unit afterwards.
(3) Anyone know where the blue and live wire go back into choc block?! ( I usually photograph things before pulling them apart and I didn't this time. Doh!

Photos attached and writing on component appears to be : "microtemp... "
SPJABC
G4A00
T subscript F 128 C

ANOTHER EDIT: This states the fuse has blown. So, should I just replace it without looking for what blew it or try to find what blew it - some of white tape around windings look a little brown. Fan came from his bathroom.
http://www.thermodisc.com/en-US/Pro.../Microtemp®_Thermal_Fuse_Product_Bulletin.pdf

 

[nigelmercier]

Short the fuse out, if the motor burns up, bin it. If it runs OK, replace the fuse.

 

[malpasman]

Hi

Looks like a heat fuse, check that the spindal is not tight, if so, needs lubricating with 3 in one or similar.

To test, short out the fuse.



Regards MM

 

[VicS]

I have a similar problem from time to time with the fan in our cooker hood.

The the bearings dry out... the motor stops, or at least overheats, and the fuse goes ... but mine is a resettable one ( see below) .. so I oil the bearings put it all back together and off it goes for another 2 or 3 years before the same thing happens ( although I have also had to fit a couple of brass washers in place of some nylon?? thrust washers which wore out)

Replace the fuse, oil the motor bearings, make sure it all runs freely and with luck it'll keep going for a few more years.

 

[tim_ber]

I have a similar problem from time to time with the fan in our cooker hood.

The the bearings dry out... the motor stops, or at least overheats, and the fuse goes ... but mine is a resettable one ( see below) .. so I oil the bearings put it all back together and off it goes for another 2 or 3 years before the same thing happens ( although I have also had to fit a couple of brass washers in place of some nylon?? thrust washers which wore out)

Replace the fuse, oil the motor bearings, make sure it all runs freely and with luck it'll keep going for a few more years.

Thanks Vic,

I looked at the bearings firstly as you say, and I could still see clear beautifully silky grease in their and it span smoothly, so that was when I started looking at the motor windings (because the circuit board was mint too)

Many thanks all.

Going to do a test now and make sure everyone else is standing back and wife has a baseball bat (wooden one) in her hand (standard practice when I am messing with 240Volts - as consumer unit is long way away). I wonder if she'll wack me with it even if I don't get a shock?

 

[tim_ber]

Short the fuse out, if the motor burns up, bin it. If it runs OK, replace the fuse.

Thanks Nigel. I posted a reply here before I replied to Vic and it vanished.

I did say....

Great minds think alike because just before I logged on here to see if there were any replies I wondered to myself if I could put what I call a jumper - yes the woolly kind - across the fuse and see if anything worked to save time waiting for a fuse.

However, your mind is far greater than mine and quicker too - it only took me about 12 hours to think of the jumper.

So you see, I am learning from you guys - slowly but surely.

Many thanks.

Going to copy this in case it fails to post and then paste it.

 

[nigelmercier]

I wonder if she'll wack me with it even if I don't get a shock?

I never work on any live gear without plugging in via a 10mA RCD:

http://cpc.farnell.com/pro-elec/inlinercd/rcd-in-line/dp/PL10474

 

[tim_ber]

I never work on any live gear without plugging in via a 10mA RCD:

http://cpc.farnell.com/pro-elec/inlinercd/rcd-in-line/dp/PL10474

Success or not...

Baseball not req'd - I did do it via a surgeprotector trailing socket that powers the computers because I've lost my RCD from the garage - you see there I go again, along the right lines, but not anywhere near yet.

Anyway......

I wired the live and neutral back to where I thought they would go, got my jumper ready, flicked the switch, and the damn (dam - just in case spelling bot removes 'swear' word) fan started. Still no continuity across fuse - i must be doing something wrong there I guess.

So either Murphy and his Law got in there, or juggling around with it loosened something up or someone had the neutral and live in wrong place on choc blocks before (there are witness marks where someone has had a screwdriver behind motor spindle).

Really I should now swap neutral and live and see if it stops working, but I won't because I think that is stupid and dangerous, so I am going to go with Murphy and tell neighbour, it's working now - don't know why - be careful, keep an eye on it (it is up high and can't be touched in his bathroom, but obviously he has to make sure his house wiring is all protected properly (in an old timber framed house).

Unless any of you guys have got a better idea, because I enjoyed all that, but my mental resources are now used up.

Thanks for all the input though - I do like fixing things, but prefer it when I know what / how I fixed it !

EDIT - just clicked that link - that is going in my shopping basket - lovely bit of kit - thanks again, Nigel - you da man.

 

[nigelmercier]

EDIT - just clicked that link - that is going in my shopping basket - lovely bit of kit - thanks again, Nigel - you da man.

I've got one of these feeding my workbench power strip at home, and another on the boat with a 16A plug on one end, and a dual socket outlet on the other.

10mA RCD: http://cpc.farnell.com/pro-elec/inlinercd/rcd-in-line/dp/PL10474
16A plug: http://cpc.farnell.com/walther/210306cl/3p-240v-bs4343-clear-plug-blue/dp/CN06701
Dual socket: http://cpc.farnell.com/pro-elec/0139-or/socket-rubber-2-gang-13a-orange/dp/PL0947003

Note that the RCD is very sensitive (which is the whole point), and often trips when you plug in.