I bought a new car wiper motor from Ebay for a project. When sorting out
what does what with the connections to it, I accidently reversed it.

It is a fairly standard permanent magnet type with three brushes - the
extra one for the second speed.

When I first powered it up it made a few strange noises then settled down
to running ok. When I reversed it, it ran a few revolutions then locked
solid. Applying the current the correct way didn't shift it.

Investigation showed the ferrite magnets to be cracked in several places
with some smallish bits broken off completely and jamming the armature.
Removed those bits and it ran again.

Can I just confirm this was likely caused by it being dropped at some time
and not by reversing it?

--
*If a pig loses its voice, is it disgruntled?

Dave Plowman London SW
To e-mail, change noise into sound.

In message , "Dave Plowman (News)"
writes
I bought a new car wiper motor from Ebay for a project. When sorting out
what does what with the connections to it, I accidently reversed it.

It is a fairly standard permanent magnet type with three brushes - the
extra one for the second speed.

When I first powered it up it made a few strange noises then settled down
to running ok. When I reversed it, it ran a few revolutions then locked
solid. Applying the current the correct way didn't shift it.

Investigation showed the ferrite magnets to be cracked in several places
with some smallish bits broken off completely and jamming the armature.
Removed those bits and it ran again.

Can I just confirm this was likely caused by it being dropped at some time
and not by reversing it?

I can't see how reversing the supply could possibly have broken the
magnets.
--
Ian

In article , Dave Plowman (News)
writes
I bought a new car wiper motor from Ebay for a project. When sorting out
what does what with the connections to it, I accidently reversed it.

It is a fairly standard permanent magnet type with three brushes - the
extra one for the second speed.

When I first powered it up it made a few strange noises then settled down
to running ok. When I reversed it, it ran a few revolutions then locked
solid. Applying the current the correct way didn't shift it.

Investigation showed the ferrite magnets to be cracked in several places
with some smallish bits broken off completely and jamming the armature.
Removed those bits and it ran again.

Can I just confirm this was likely caused by it being dropped at some time
and not by reversing it?

Does the park function still work?

My thought is that if the park switch mechanism was incredibly badly
designed it could rely on one way operation and by reversing it, the
mech could have been damaged causing something to break off and damage
the magnets.

If the sole cause of the reverse stall was the magnet fragments then it
should now operate continuously in reverse. I can understand of course
if you prefer not to risk it in reverse again to find out.
--
fred
FIVE TV's superbright logo - not the DOG's, it's ********

In article ,
fred wrote:
Can I just confirm this was likely caused by it being dropped at some
time and not by reversing it?

Does the park function still work?

It's a simple common micro-switch driven off a cam on the main gear wheel.
And all the gearbox part is just fine.

My thought is that if the park switch mechanism was incredibly badly
designed it could rely on one way operation and by reversing it, the
mech could have been damaged causing something to break off and damage
the magnets.

The motor is quite separate from the gearbox - only the worm drive pokes
through into the gearbox housing.

If the sole cause of the reverse stall was the magnet fragments then it
should now operate continuously in reverse. I can understand of course
if you prefer not to risk it in reverse again to find out.

I'm not inclined to risk using it at all - as other fragments of the
magnet might break off through normal vibration etc.

--
*The most common name in the world is Mohammed *

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Dave Plowman (News)
writes
In article ,
fred wrote:
Can I just confirm this was likely caused by it being dropped at some
time and not by reversing it?

Does the park function still work?

It's a simple common micro-switch driven off a cam on the main gear wheel.
And all the gearbox part is just fine.

My thought is that if the park switch mechanism was incredibly badly
designed it could rely on one way operation and by reversing it, the
mech could have been damaged causing something to break off and damage
the magnets.

The motor is quite separate from the gearbox - only the worm drive pokes
through into the gearbox housing.

If the sole cause of the reverse stall was the magnet fragments then it
should now operate continuously in reverse. I can understand of course
if you prefer not to risk it in reverse again to find out.

I'm not inclined to risk using it at all - as other fragments of the
magnet might break off through normal vibration etc.

Ah well, it was just a thought. Given that it does point to some kind of
physical abuse such as dropping as you suggest.
--
fred
FIVE TV's superbright logo - not the DOG's, it's ********

In article ,
fred wrote:
Ah well, it was just a thought. Given that it does point to some kind of
physical abuse such as dropping as you suggest.

Guess so - I was really just making conversation on a quiet day. ;-)

I bought it from an Ebay seller who didn't usually sell this sort of
thing. He also cancelled the transaction after I'd bought and received it
- which I thought strange. However, I got it cheaply - about 10% of the
retail price. I've bid on another secondhand one - swapping the cover
containing the magnets should give me a good as new one.

--
*Why is the word abbreviation so long?

Dave Plowman London SW
To e-mail, change noise into sound.

On Dec 29, 1:10*pm, "Dave Plowman (News)"
wrote:
In article ,
* *fred wrote:

Ah well, it was just a thought. Given that it does point to some kind of
physical abuse such as dropping as you suggest.

Guess so - I was really just making conversation on a quiet day. ;-)

I bought it from an Ebay seller who didn't usually sell this sort of
thing. He also cancelled the transaction after I'd bought and received it
- which I thought strange. However, I got it cheaply - about 10% of the
retail price. I've bid on another secondhand one - swapping the cover
containing the magnets should give me a good as new one.

I wonder what the life expectancy of Brits would be if we drove cars
with all parts bought from ebay


NT

In article
,
Tabby wrote:
I bought it from an Ebay seller who didn't usually sell this sort of
thing. He also cancelled the transaction after I'd bought and received
it - which I thought strange. However, I got it cheaply - about 10% of
the retail price. I've bid on another secondhand one - swapping the
cover containing the magnets should give me a good as new one.

I wonder what the life expectancy of Brits would be if we drove cars
with all parts bought from ebay

I've bought lots of stuff from Ebay and been generally satisfied. Just as
likely to get faulty parts elsewhere, IMHO.

--
*Keep honking...I'm reloading.

Dave Plowman London SW
To e-mail, change noise into sound.

Tabby wrote:

I wonder what the life expectancy of Brits would be if we drove cars
with all parts bought from ebay

Longer, if my recent experience is anything to go by.

I bought rear self levelling shocks (£25 a pair, UK dealer price £500),
four brake disks, four hub bearings, four sets of pads, two handbrake
shoes (£300 the lot, UK dealer price about £2000) and fitted them over a
weekend. The ride and handling of the car was greatly improved, stopping
distance shortened significantly, brake fade when descending mountains
eliminated.

"I'd say it's a major contribution to road safety."

Tabby wrote:
On Dec 29, 1:10 pm, "Dave Plowman (News)"
wrote:
In article ,
fred wrote:

Ah well, it was just a thought. Given that it does point to some kind of
physical abuse such as dropping as you suggest.
Guess so - I was really just making conversation on a quiet day. ;-)

I bought it from an Ebay seller who didn't usually sell this sort of
thing. He also cancelled the transaction after I'd bought and received it
- which I thought strange. However, I got it cheaply - about 10% of the
retail price. I've bid on another secondhand one - swapping the cover
containing the magnets should give me a good as new one.

I wonder what the life expectancy of Brits would be if we drove cars
with all parts bought from ebay

Little different to what it is today.



NT