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OSIM uSqueez foot massager sparking how to?


OSIM uSqueez permanently dead. Dismantled unit found mother board 2A fuse blown. Check everything OK on mother board and replace fuse. Power on unit led under stop button light up. Pressed vibrator button works perfect. Pressed massage button strong sparking sound and saw fire in one to two second followed by blown fuse.

1. Measure the motor terminal resistance -> 0 ~ 5 ohms. Or it should should have some high resistance approximately 10 ~ 50 ohms.
2. Measure BR-B3D thermal protector which was in series with the black wire -> 0 ~ 5 ohms.

Any idea which one is faulty part?

1. Think the thermal fuse is OK.
2. If the motor short, shall I do rewinding for rotor? Can't found this motor locally and if buy direct from OSIM too expensive!

Any idea measure rotor coil?

Thanks

Picture of OSIM uSqueez foot massager sparking how to?
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iceng3 months ago

Black powder is carbon residue as brushes are eaten away, bar to bar by impulse high current over 20 times rated current...

Do try to slowly turn the armature while measuring terminal resistance and see if it varies a lot over 360 degree slowly turning..

tplim (author)  iceng3 months ago

@iceng

Thanks for reply. Will update here once done cause need to disassemble the unit again.

P/S: At present do some test on scooter motor. While turning 360 degree results vary between 0 ~ 300 ohms.

iceng3 months ago

While I was never be able to visually tell if a thermal fuse was OK or Not ?

I know a sparking fire is a very very bad sign for a motor and could be a damaged commutator or brushes, after which terminal resistance would vary greatly as the armature is slowly rotated (turned)...

tplim (author)  iceng3 months ago

@iceng, @Jack A Lopez

With reference to my earlier info.

"Therefore assemble back the whole unit and temporary just use the vibrator." During this process, do check the gearbox with the motor attached, it was totally stuck (none movable even force being apply).

I do believe the thermal fuse is OK cause no sign of damage or burn at the body. Google around web couldn't find any guide what it resistance suppose to be. With multimeter it resistance reading 0 ~ 5 ohms. Based on my knowledge it should read 0 ohm (for fuse).

Ah Har, but motor do not have knowhow. Once I did disassemble the motor, inside the body found some fine black powder (it could be from magnet or brushes due to spark and burn).

My question is:

1. How to check or verify the motor amatuer?

2. Do you think the winding itself is shorting each other due to spark and burn?

3. What is the expected resistance for all the winding once joint to produce two terminal negative (-) and positive (+). PS: Not sure the winding was connected in series or parallel.

4. Finally how to measure the individual winding.

Thank you in advance for your valuable time spend here.

Jack A Lopez3 months ago

Is there any way to feel if the motor shaft, plus attached gears, are free to turn?

Electrically, a jammed, stalled motor acts like a short, and it can blow a fuse in this condition.

You might try disconnecting the motor from its gearbox, to see if this gizmo will go, "whirrrrrrrrrrrrrr," and make the motor spin when it's supposed to spin, without blowing the fuse. I mean it would not be able to massage your feet in that condition, but it would suggest the motor and electronics were fine, and the problem was in mechanical resistance in the gearbox.

Regarding motors, DC motors like this are inexpensive when sold by surplus mongers like electronic-goldmine, bgmicro, and others.

http://www.goldmine-elec-products.com/products.asp...

I mean, that is if you can find a motor with the same shaft size and shape, and that can be tricky. If you can find that motor shaft with exactly the right size and shape, much like Cinderella's magic glass slipper, then it will be cheap, if you can get it through the surplus mongers.

Also do not rule out the possibility of finding it cheaper, like in a dumpster, or thrift store, in a broken something or other, that someone else threw away.

I hate to recommend eBay to anyone, but at least what is offered there is easy to search through.

But, it also might be the case you do NOT need a new motor. I mean, try working on that gearbox, for to see if you can get it loosened up, or lubed up, maybe with some spray lubricant, or petrolatum, or a combination of those.

tplim (author)  Jack A Lopez3 months ago

Thank you for the reply.

1. Just upload the motor itself.

2.
"You might try disconnecting the motor from its gearbox, to see if this
gizmo will go, "whirrrrrrrrrrrrrr," and make the motor spin when it's
supposed to spin, without blowing the fuse." Connected the motor (second
photo) without gearbox fuse blown too. Dismantle the motor check both
bearing on the shaft ok. Fit back the motor but forget to manually turn
the shaft. Than power up again blown fuse. Therefore assemble back the
whole unit and temporary just use the vibrator.

3."... suggest the
motor and electronics were fine, and the problem was in mechanical
resistance in the gearbox." Manually playing around gearbox without
motor, freely run.

4. For your info, I do not have know how about motor. As I knew the resistance close to 0 ohm.

Regards

IMG_2870.JPG

+1

Cannot add any more to that well diagnosed foot err thingy

Especially an goldmine user.. -.-. .--. -.