Reviving a YDK Motor

[beko1987]

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So, I have one machine left to refurb, and it has a noisy motor. Bearings are shot, it's hard to spin by hand.

I also had a YDK motor that had burnt its carbon brushes out with smooth bearings



Lets see if we can make one good motor out of two

Outer shroud tapped off



Fan out







Few taps with a hammer and the armature with the bad bearings but good carbons falls out



This armature spins beautifully



But the carbons did this



I bench tested it before and there were a few gloopy blue sparks and no movement!

The other carbons were just good enough for me to try them



Gave them a light clean with some fine wire wool to level the surface out

Also cleaned up the commutor on the good bearings part





The carbons may not be good enough, but we shall see tomorrow!



One good* motor! Yet to be tested as it was too late for me to fire it up in the garden when done, but will fit it back into a motor housing first incase it blows up in my hand, and if it spins nicely I'll havea closer look to check



If it works then I'll experiment with replacing carbon brushes next!

[MVacs]

Its a funny thing, but as long as I have been doing this, I have never had one of those motors apart like that.

I predict it will spark like a firework. Waiting for the update. 

[beko1987]

Well I had a quick test run and....

Perfick! Ran sweet, no sparking at all! Will put the machine back together and use it for a few days to check.

Will get some carbons on my next order and wait to find another suitable candidate for testing! The rest of the other motor is in the bin however as I haven't got the tools to pull the bearings off, and a bearing pulled and bearings will cost several motors anyway so not much point!

[MikeR]

Hi,

Very brave of you going to all that trouble without measuring the armature windings first! I have never had one of these dyson motors that isn't showing signs of the armature failing. If one brush is worn more than the other, then the armature is starting to fail!  I would measure the armature windings to be sure, each should measure about 400mΩ. If there are any variations, its on its way out. Hopefully you are lucky and have a motor that will last.
Bring back the good old days! As an apprentice I was changing armatures, brushes and bearings daily.

Well done

Keith

[beko1987]

Cheers Keith!

Not actually done anything with this yet as I havent put the machine back together! But what tools would I need to measure the windings?

It spins smoothly by hand, and the carbons dont 'click' over each segment, which I would expect it to if they were goosed. TBH I did one part with the wire wool expecting it to reveal pitting etc, and carried on when it didnt!

[MikeR]

You need a good quality low ohms meter that will give consistent readings. I use a Megger insulation tester that has a low ohms range for checking earth bonding, but probably not worth getting one if you don't have one, you could probably get a good second hand one for about £150. A standard multimeter is not accurate or consistent enough for these low ohms measurements, unless you have paid a couple of grand for it! Some ESR meters have a low ohms range, but still cost £100 for a good one.

You could measure the resistance across the brushes with a multimeter and slowly move the armature a little at a time, the reading should stay roughly the same. This method isn't as accurate. Please note that when the armature is rotated a voltage is produced, like an alternator!!!

Keith

[beko1987]

I might try the OHMS across the brushes first, I found my multimeter the other day, keep meaning to learn how to use it!

Think I'll carry on going by eye for now though. Still havent got the ruddy machine back together and tested properly yet, really must do that this weekend!

[beko1987]

Dc07 with a rebuilt YDK motor:

On my phone so that probably won't be correct, I'll fix it later but it should copy and paste...

But the motor works well! Sounds fine, didn't get hot etc. Will run it for a week or so to check then off for sale it goes!

[DaiDyson]

Hi beko1987, I know this is an oldish thread but wondered how you kept the shaft still to undo the bolt?

Cheers!

Simon

[beko1987]

Molegrips! Just be careful to not let them slip and chew the belt pulley up!

[DaiDyson]

Thanks, I did manage to do it with some needle-nosed pliers in the end but it was all a bit too damaged inside to recondition anyway.

[beko1987]

Having done this a few times before, now I hold the fan still with my hand clamped on it, the ncrack the nut undone (the wrong way, it's a left hand thread).

I chewed up the belt pulley on another hovoer motor trying to hold it still, so don't do that now (luckily I had a spare armature!)

Thought I would bump this up since Parwaz is looking at doing this!

[Tech12]

A pair of cheap leather palmed gloves might help with grip & save your hands.

[beko1987]

I put a folded over microfibre over it then hold that sometimes if they are a bit stubborn

[Tech12]

Don't blame you mate, they can wreck your palms.