Appliance AC motor armature repair and perhaps new carbon brushes.  Anyone know a shop that can do this?

 

Motor in question is made in italy and not available locally.

1 hour ago, atyclb said:

Appliance AC motor armature repair and perhaps new carbon brushes.  Anyone know a shop that can do this?

 

Motor in question is made in italy and not available locally.

The shop locally will rebuild a motor in Non Sa-At, Udon Thani.

bangkok shops?

1 hour ago, atyclb said:

bangkok shops?

 

Check out the Ban Mo / Thip Wari Alley area around the Old Siam Plaza. There are guys in the street rewinding Hatari fans I'm sure there will be someone who can re-build your motor.

 

Are you sure the armature is fried? A decoke of the comm and new brushes can make a world of difference. 

41 minutes ago, Crossy said:

 

Check out the Ban Mo / Thip Wari Alley area around the Old Siam Plaza. There are guys in the street rewinding Hatari fans I'm sure there will be someone who can re-build your motor.

 

Are you sure the armature is fried? A decoke of the comm and new brushes can make a world of difference. 

 

cool thanks. what do u suggest to use to decoke?  any source of brushes?  its a motor inside semi commercial coffee grinder

Many instructional videos on youtube, solvent, pointy thing to clean the slots, light abrasive paper.

 

For example https://www.youtube.com/watch?v=oB-h-vZc6FY

 

Brushes tend to be standard sizes, have a hunt on aliExpress for something the same size or tout them round Ban Mo.

 

Does it still run?

 

 

6 hours ago, Crossy said:

Many instructional videos on youtube, solvent, pointy thing to clean the slots, light abrasive paper.

 

For example https://www.youtube.com/watch?v=oB-h-vZc6FY

 

Brushes tend to be standard sizes, have a hunt on aliExpress for something the same size or tout them round Ban Mo.

 

Does it still run?

 

 

great video.  

 

runs but seems to have lost torque and starts slower then speeds up.

18 hours ago, Crossy said:

 

Check out the Ban Mo / Thip Wari Alley area around the Old Siam Plaza. There are guys in the street rewinding Hatari fans I'm sure there will be someone who can re-build your motor.

 

Are you sure the armature is fried? A decoke of the comm and new brushes can make a world of difference. 

 

have isolated motor. will decoke it and clean in general. motor has 2 capacitors. they both appear intact, no bulging, leaking, corrosion.  should i replace them?

 

i cleaned brushes which are spring loaded and appear ok.  

The long round things are actually inductors for interference suppression, they should show a short-circuit with your meter. Not a lot to go wrong there.

 

The brushes look ok, maybe a little short (worn). When you put them in how much spring compression is there? I would expect to push them at least 4mm to get the armature in.

 

Do the brushes move freely in their slots?

 

1 hour ago, Crossy said:

The long round things are actually inductors for interference suppression, they should show a short-circuit with your meter. Not a lot to go wrong there.

 

The brushes look ok, maybe a little short (worn). When you put them in how much spring compression is there? I would expect to push them at least 4mm to get the armature in.

 

Do the brushes move freely in their slots?

 

 

 

yes at least 4mm compression and they move freely.   

 

what is suggested correct lubricant for shaft?

3 hours ago, atyclb said:

what is suggested correct lubricant for shaft?

 

Those look like sintered bronze bearings. Theoretically they should be impregnated with a special grease (needs heat and pressure). 

 

For a DIY a typical light machine oil (sewing machine oil) should be OK, it won't last as long as original, but it's far better than nothing.

 

EDIT Not a bearing, but the principle is the same.

 

 

 

Fancy a bit of DIY sucking?

 

https://www.instructables.com/id/Making-A-Fridge-Compressor-Into-A-Vacuum-Pump/

 

 

4 minutes ago, Crossy said:

Fancy a bit of DIY sucking?

 

https://www.instructables.com/id/Making-A-Fridge-Compressor-Into-A-Vacuum-Pump/

 

 

 

great idea

With an armature you need to examine to commutator closely, not a girls look, you need a really close examination. Checked all the comm segments and insulated gaps they must all be the same not similar. Colours, widths, depths, heights etc. The face of the brush should be smooth and uniform. Looking at your photos it looks like you need to make a critical look at the comm as it looks like some colour change but it just may be the light in the photo. The brush faces don’t look normal either. It all indicates to me that the comm is coming apart so pretty much your screwed.


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On 3/7/2019 at 6:18 PM, Wirejerker said:

With an armature you need to examine to commutator closely, not a girls look, you need a really close examination. Checked all the comm segments and insulated gaps they must all be the same not similar. Colours, widths, depths, heights etc. The face of the brush should be smooth and uniform. Looking at your photos it looks like you need to make a critical look at the comm as it looks like some colour change but it just may be the light in the photo. The brush faces don’t look normal either. It all indicates to me that the comm is coming apart so pretty much your screwed.


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thanks for thoughts. i looked at the comm closely with a good light and it seems to e ok.  you are right the brush faces were not completely smooth and uniform.

 

now motor is slowing down.  what if i use sandpaper around comm to smooth brush faces?

 

are comm's alone available as replacement parts?

 

Thanks

No the comm is not a replaceable part

Check the face has nothing stuck on it.. if it’s only carbon rot will clean itself up if every thing is okay. Check the brushes are not at the end of travel.
Do the brushes throw a lot of sparks?

Are you sure it’s not the grinder putting too much load on the motor, that can make the brushes work hard. Have you removed the conical burr and cleaned inside, burrs clean, no foreign objects, tried turning it by hand.


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34 minutes ago, Wirejerker said:

Are you sure it’s not the grinder putting too much load on the motor, that can make the brushes work hard. Have you removed the conical burr and cleaned inside, burrs clean, no foreign objects, tried turning it by hand.

 

An excellent point, why didn't I think of that?

 

3 hours ago, Wirejerker said:

No the comm is not a replaceable part

Check the face has nothing stuck on it.. if it’s only carbon rot will clean itself up if every thing is okay. Check the brushes are not at the end of travel.
Do the brushes throw a lot of sparks?

Are you sure it’s not the grinder putting too much load on the motor, that can make the brushes work hard. Have you removed the conical burr and cleaned inside, burrs clean, no foreign objects, tried turning it by hand.


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first thing i did was remove conical burrs, impeller and clean everything. burrs fairly new also. after isolating motor i see it is running slow (without any load applied)

 

just a few small brush sparks

I’m about out of ideas. It could be an open circuit in the fields or suppressors. Take crossy’s original advice and take it to a motor rewinder


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On 3/6/2019 at 2:31 PM, atyclb said:

bangkok shops?

YES Within 50m of Phrakanong BTS. They will fix it for you. It is on the soi that runs at about 45 degrees from Sukhumvit (was 46) behind Starbucks. 

On 3/7/2019 at 10:53 AM, atyclb said:

motor has 2 capacitors. they both appear intact, no bulging, leaking, corrosion.  should i replace them?

Generally speaking capacitors are the least reliable electronic component. YES replace them. Or buy a cheap multimeter that has a capacitor test setting.

1 hour ago, atyclb said:

after isolating motor i see it is running slow (without any load applied)

You need to perform the basic commutator bar and field winding checks using a test meter. A motor repair shop will do this if you don't have the necessary equipment.

Those little black things marked 15.0 uH (micro Henry’s) are inductors


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39 minutes ago, VocalNeal said:

On 3/6/2019 at 2:31 PM, atyclb said:

bangkok shops?

YES Within 50m of Phrakanong BTS. They will fix it for you. It is on the soi that runs at about 45 degrees from Sukhumvit (was 46) behind Starbucks. 

 

 

better than the places at ban mor . near dee old siam?

1 hour ago, atyclb said:

better than the places at ban mor . near dee old siam?

 

Certainly easier to get to ????

 

https://goo.gl/maps/VjNnCSeNKx42

 

The beam mounted hoist gives an idea of their capacity? And the can rewind small transformers. 

 

 

1 hour ago, VocalNeal said:

https://goo.gl/maps/VjNnCSeNKx42

 

The beam mounted hoist gives an idea of their capacity? And the can rewind small transformers. 

 

 

 

went there. good thing they have the hoist as it did actually lift my motor out of backpack 55

 

800 baht to repair and 2 month guaranty

 

new motor 1200 baht italy plus shipping

Have they fixed it already?

 

Any indication as to the problem?

 

Definitely one for the "useful places" list ????

 

 

On 3/9/2019 at 1:48 PM, Crossy said:

Have they fixed it already?

 

Any indication as to the problem?

 

Definitely one for the "useful places" list ????

 

 

 

the lady at desk pointed to comm brush/winding area but i dont think she is a technician though she likely has experience with many motors being received and fixed.

 

it will be ready next thursday.  800 baht and i left a 100 baht deposit.

 

i will take the grinder with me thursday and install motor and test with coffee beans just to make sure repair is ok.  correct rpm and torque.

fyi this is grinder