In article ,
"Brian" writes:

I'll put this into a little table to see if that helps:
The table was done in notepad in courier new if the formatting
is a mess in your reader.

The format works fine.

1 2 3 4 5 6 7
Purple White White White Red/Blue White White
-6,7 Armature Armature -1,5 -1,4 -7(1k6) -6 (1k6)
0V ~235V 0V 0 ~230V ~160V ~160V

Any ideas? Is the motor goosed .. Control unit? Or does none
of this make sense to anyone?

If there's really 235V across the armature and the motor
isn't turning, then there will be clouds of smoke within
a few seconds. This implies there is a break somewhere in
the armature circuit. One possibility is that there is a
one broken armature winding and the motor happens to have
stopped with the brushes on that one. Maybe the brushes
are not making proper contact with the commutator?

After you've had power on the motor (and isolated it
again), are any of the windings warm (be careful as they
could be very hot)? I presume you can spin the motor by
hand with the power off, i.e. it hasn't got a ceased
bearing?

I do find it odd that so much ac voltage seems to be
going over what I guess is a tachometer, and that nothing

Not possible to tell directly from your measurements, but
it looks to me like there could well be no voltage across
the tachometer as both sides measured the same voltage.

is going into the all important purple wire. On the other hand,
there is a lot of voltage going in for little action!

1, 4 and 5 are presumably the field windings. It looks
like 1 and 5 or 4 and 5 have a supply on them, and the
other connection is probably for operating the motor at
a completely different power/speed, such as the final spin.

BTW, don't try operating the motor with no load. In theory,
the microprocessor should limit the speed using the tacho,
but in mine the microprocessor crashes if you run the
motor with no load, and hence fails to limit the speed
or stop the motor (have to power off the machine).
Washing machine motors when run with no load and no speed
control can way over-rev, and cause the armature to
explode into pieces.

I have had brush failure on a motor also blow the SCR
(semi conductor power switch) on the control board, but
the evidence you have presented so far doesn't point to
this having happened.

--
Andrew Gabriel

1 2 3 4 5 6 7
Purple White White White Red/Blue White White
-6,7 Armature Armature -1,5 -1,4 -7(1k6) -6 (1k6)
0V ~235V 0V 0 ~230V ~160V ~160V

Any ideas? Is the motor goosed .. Control unit? Or does none
of this make sense to anyone?


If there's really 235V across the armature and the motor
isn't turning, then there will be clouds of smoke within
a few seconds. This implies there is a break somewhere in
the armature circuit. One possibility is that there is a
one broken armature winding and the motor happens to have
stopped with the brushes on that one. Maybe the brushes
are not making proper contact with the commutator?

Thanks for the reply. Perhaps I wasn't clear in the
original post but I did the above voltage readings
straight out of the connector that goes into the
motor, WITHOUT the motor attached. Maybe this was
... stupid, but its not easy to access them otherwise,
and I was running out of ideas. I wanted to see
what was being sent, unloaded. I suppose it may ramp
up the voltage in order to power the ghost motor.
But it did show it wants to stick power out.

Prior to this I got about 7-8 ohms across the armature pins
of the unconnected motor so I assumed the brushes touched
ok, and that was the total impedance across the windings.

After you've had power on the motor (and isolated it
again), are any of the windings warm (be careful as they
could be very hot)? I presume you can spin the motor by
hand with the power off, i.e. it hasn't got a ceased
bearing?

Its definitely not ceased. I'll see if I can check for
warmth later.

I do find it odd that so much ac voltage seems to be
going over what I guess is a tachometer, and that nothing

Not possible to tell directly from your measurements, but
it looks to me like there could well be no voltage across
the tachometer as both sides measured the same voltage.

Ahh I see your point, if both are in phase.
Hmm. Don't know whats supposed to be across it.
I kind of imagined it would be a signal out that is induced,
with nothing passed INTO it.

is going into the all important purple wire. On the other hand,
there is a lot of voltage going in for little action!

1, 4 and 5 are presumably the field windings. It looks
like 1 and 5 or 4 and 5 have a supply on them, and the
other connection is probably for operating the motor at
a completely different power/speed, such as the final spin.

Ok.

BTW, don't try operating the motor with no load. In theory,
the microprocessor should limit the speed using the tacho,

Yes thanks, I read that on the net. I'm surprised there
isn't a 'here is how hotpoint wire their motors' article,
but I just can't find one anywhere.

One final note - the controller block is definitely a lot
noisier than it used to be. But everything else (pumps / heat
etc) all work. Its just the motor won't turn.

I was trying to get the controller out to have a look at the
solder joints on the bottom but can't seem to get at a
couple screws. Maybe thats for tommorow!

"Brian" wrote in message
...
I've got a hotpoint washer / dryer that isn't rotating the
motor. So I'm hoping to find a hotpoint or motor
expert who can help me..

So heres an interesting puzzle for you -

The motor says on it AC motor for electronic speed control,
1 phase. (904/1153/10). This is UK 240v.

snipped
Thanks in advance.
Brian.


The speed control circuit board may be duff. These motors are controlled by
pulsed voltage from a circuit board positioned on the casing somewhere.
Usually near the top of the machine to keep them from getting wet in a leak
fault. The motor only gets full voltage, no matter what speed it's meant to
be running at, but the voltage is pulsed so makes the motor surge, slow,
surge, slow and so on and so on. and this keeps it at a steady speed.

Connections to the motor are for mains voltage and tachometer coil. The
mains voltage is obvious, but the tachometer works by detecting the motor
speed from a spinning magnet which is fixed to the end of the armature. The
faster the magnet spins, the more it effects the tachometer coil, the more
the control circuit board pulses the voltage.

Take a look at the circuit board and see if it has signs of overheating on
it. This is most noticeable near the black thing with three wires coming
from it, and is most likely fitted to a bit of metal to dissipate the heat
it generates away from it. The other place overheating can be seen is near
quite large black cylinder shaped components that have a silver or white
stripe at one end. These control the pulsing times for the mains voltage to
the motor, and they can boil over time.

One test you can do, but be very careful when attempting it, is to wire a
bit flex cable with a plug on it to the motor. You've already traced out
where the connections for motor are, so make these connections and test the
motor works outside the machine. Then you'll know it's control board that's
duff for sure.

Place the motor on a wooden board, and keep the socket where the plug goes
well within arms reach so you can switch off quickly. A 5 Amps fuse in the
plug is enough for this test. Place a foot on the motor in case it jumps
around when you apply the mains to it. That Centrifugal stuff can be a
bitch sometimes.

It's the only other thing I can think of to make sure of what part is gone
tits up on you.

Good luck with it.

Thanks for answering,

The speed control circuit board may be duff. These motors are
controlled by pulsed voltage from a circuit board positioned on the
casing somewhere. Usually near the top of the machine to keep them
from getting wet in a leak fault.

Yes, I can see it. I've found the replacement part for this module
on the web. 25 quid I think it was.

The motor only gets full voltage,
no matter what speed it's meant to be running at, but the voltage is
pulsed so makes the motor surge, slow, surge, slow and so on and so
on. and this keeps it at a steady speed.

Ahh ok. So an oscilloscope would be handy!


Take a look at the circuit board and see if it has signs of
overheating on it. This is most noticeable near the black thing with
three wires coming from it, and is most likely fitted to a bit of
metal to dissipate the heat it generates away from it. The other
place overheating can be seen is near quite large black cylinder
shaped components that have a silver or white stripe at one end.
These control the pulsing times for the mains voltage to the motor,
and they can boil over time.

Hmmm I've now got the controller and module out...
AHA! It wasn't obvious, as the module had a load of visible components,
then some under a heatsink. Now that I have it in my hands with a
torch:
I can see two resistors that look blackened towards the bottom corner.
And what looks like a transistor that is missing its face, right next
to another blackened resistor. Its not a power tranistor, its a ..
normal looking one next to one simlar marked C556. All these were under
the heatsink so I didn't notice until I took it apart.

So thats handy, I know that this needs replaced. I don't know what
the actual components were though, so in the abscence of a circuit
diagram or a workaround, thats a new module. One other query is,
there is a large relay I believe marked EKS EMK025 on the back
of the controler, with pin that comes out attached to a plastic
lever. It doesnt seem to move at all when its. Maybe thats for
spin mode only..

So the FINAL question is, is the motor still ok? Did it blow
and take the board with it?

One test you can do, but be very careful when attempting it, is to
wire a bit flex cable with a plug on it to the motor. You've already
traced out where the connections for motor are, so make these
connections and test the motor works outside the machine. Then
you'll know it's control board that's duff for sure.

Ok I'm game to wire it up and give it a very quick pulse of 240v.
I may do this in situ, in the machine, so its 'loaded'.

But I don't know what precisely to wire it to.
Ignoring the tachometer, thats pins 1, 4,5 all connected, and
2-3 over the armature. If you recall.

1 2 3 4 5 6 7
Purple White White White Red/Blue White White
-6,7 Armature Armature -1,5 -1,4 -7(1k6) -6 (1k6)
0V ~235V 0V 0 ~230V ~160V ~160V

Are you saying that this is the correct wiring [2 / 5] to live,
rest to neutral? But you believe the pulses may be too short
to actually do anything, even though it looks like loadsa
voltage?

In article ,
"Brian" writes:
Hmmm I've now got the controller and module out...
AHA! It wasn't obvious, as the module had a load of visible components,
then some under a heatsink. Now that I have it in my hands with a
torch:
I can see two resistors that look blackened towards the bottom corner.
And what looks like a transistor that is missing its face, right next
to another blackened resistor. Its not a power tranistor, its a ..
normal looking one next to one simlar marked C556. All these were under

Probably a BC556, a common general purpose transistor.

the heatsink so I didn't notice until I took it apart.

So thats handy, I know that this needs replaced. I don't know what
the actual components were though, so in the abscence of a circuit
diagram or a workaround, thats a new module. One other query is,

Try CPC.

there is a large relay I believe marked EKS EMK025 on the back
of the controler, with pin that comes out attached to a plastic
lever. It doesnt seem to move at all when its. Maybe thats for
spin mode only..

Two likely uses for a relay are to switch the heater
element on (high power SPST), and motor reversing
(medium power DPDT).

Spin selection on the Hotpoint controller I have is
done with a second SCR on a large heatsink.

So the FINAL question is, is the motor still ok? Did it blow
and take the board with it?

POssibly caused by bad brush contacts. That happened to me,
but I just replaced the SCR's on the board and it was OK again.
Yours sounds more significantly damaged.

One test you can do, but be very careful when attempting it, is to
wire a bit flex cable with a plug on it to the motor. You've already
traced out where the connections for motor are, so make these
connections and test the motor works outside the machine. Then
you'll know it's control board that's duff for sure.

Ok I'm game to wire it up and give it a very quick pulse of 240v.
I may do this in situ, in the machine, so its 'loaded'.

Still rather risky. The machine controller will never give
it a full power burst directly from a stationary rotor start.
It may never give it a full mains blast ever, even at max spin.

But I don't know what precisely to wire it to.
Ignoring the tachometer, thats pins 1, 4,5 all connected, and
2-3 over the armature. If you recall.

1 2 3 4 5 6 7
Purple White White White Red/Blue White White
-6,7 Armature Armature -1,5 -1,4 -7(1k6) -6 (1k6)
0V ~235V 0V 0 ~230V ~160V ~160V

Are you saying that this is the correct wiring [2 / 5] to live,
rest to neutral? But you believe the pulses may be too short
to actually do anything, even though it looks like loadsa
voltage?

If I was going to try it, I would connect the field windings
and armature in series. You will need a low resistance reading
meter to properly buzz out the 3 field winding terminals (or
look to see how they're connected, and ignore the tap one).
However, you run a real risk of destroying the motor by
doing this, and possibly destroying bits of yourself too,
without knowing much more about the motor ratings/specification.

When trying to work out what was wrong with mine, I kicked off
a fast spin cycle. It was only managing to turn the drum at
about 1 rev/second, but that seemed to be enough for the
microprocessor to decide the motor was working, at which point
it engaged the top speed spin winding. The machine damn near
took off as it shot from almost stationary to 1400RPM in about
a second, which of course it would never normally do. Those
motors are very powerful -- ISTR mine is rated 1.2kW although
it probably delivered a lot more in that second.

--
Andrew Gabriel

BigWallop wrote:

Place the motor on a wooden board, and keep the socket where the plug goes
well within arms reach so you can switch off quickly. A 5 Amps fuse in the
plug is enough for this test. Place a foot on the motor in case it jumps
around when you apply the mains to it. That Centrifugal stuff can be a
bitch sometimes.

Another idea would be to see if you could borrow a known working motor
from another person's machine. I've seen an engineer hook up a motor on
top of the drop and hold it with a big hammer :P.

pedant
There's no such thing as centrifugal, it's centripetal force. As I
understand it centrifugal suggests that the centre of motion is
repelling something outwards where as really it's Newton's law.. Unless
a force is acted upon by another force it will continue in the same
direction, that is if something is flying round the centre of motion it
will keep flying outwards. Or something like that... Maybe you should
have a look on google.
/pedant

--
Regards,
Aaron.

"Aaron" wrote in message
. uk...
BigWallop wrote:

Place the motor on a wooden board, and keep the socket where the plug
goes
well within arms reach so you can switch off quickly. A 5 Amps fuse in
the
plug is enough for this test. Place a foot on the motor in case it
jumps
around when you apply the mains to it. That Centrifugal stuff can be a
bitch sometimes.

Another idea would be to see if you could borrow a known working motor
from another person's machine. I've seen an engineer hook up a motor on
top of the drop and hold it with a big hammer :P.

pedant
There's no such thing as centrifugal, it's centripetal force. As I
understand it centrifugal suggests that the centre of motion is
repelling something outwards where as really it's Newton's law.. Unless
a force is acted upon by another force it will continue in the same
direction, that is if something is flying round the centre of motion it
will keep flying outwards. Or something like that... Maybe you should
have a look on google.
/pedant

Regards,
Aaron.


And the heavy windings on the centre of the armature are actually trying to
fly outward away from the motor, so it's centrifugal force that's at work
here. :-)

"Brian" wrote in message
...
Thanks for answering,

The speed control circuit board may be duff. These motors are
controlled by pulsed voltage from a circuit board positioned on the
casing somewhere. Usually near the top of the machine to keep them
from getting wet in a leak fault.

Yes, I can see it. I've found the replacement part for this module
on the web. 25 quid I think it was.

The motor only gets full voltage,
no matter what speed it's meant to be running at, but the voltage is
pulsed so makes the motor surge, slow, surge, slow and so on and so
on. and this keeps it at a steady speed.

Ahh ok. So an oscilloscope would be handy!


Take a look at the circuit board and see if it has signs of
overheating on it. This is most noticeable near the black thing with
three wires coming from it, and is most likely fitted to a bit of
metal to dissipate the heat it generates away from it. The other
place overheating can be seen is near quite large black cylinder
shaped components that have a silver or white stripe at one end.
These control the pulsing times for the mains voltage to the motor,
and they can boil over time.

Hmmm I've now got the controller and module out...
AHA! It wasn't obvious, as the module had a load of visible components,
then some under a heatsink. Now that I have it in my hands with a
torch:
I can see two resistors that look blackened towards the bottom corner.
And what looks like a transistor that is missing its face, right next
to another blackened resistor. Its not a power tranistor, its a ..
normal looking one next to one simlar marked C556. All these were under
the heatsink so I didn't notice until I took it apart.

So thats handy, I know that this needs replaced. I don't know what
the actual components were though, so in the abscence of a circuit
diagram or a workaround, thats a new module. One other query is,
there is a large relay I believe marked EKS EMK025 on the back
of the controler, with pin that comes out attached to a plastic
lever. It doesnt seem to move at all when its. Maybe thats for
spin mode only..

So the FINAL question is, is the motor still ok? Did it blow
and take the board with it?

One test you can do, but be very careful when attempting it, is to
wire a bit flex cable with a plug on it to the motor. You've already
traced out where the connections for motor are, so make these
connections and test the motor works outside the machine. Then
you'll know it's control board that's duff for sure.

Ok I'm game to wire it up and give it a very quick pulse of 240v.
I may do this in situ, in the machine, so its 'loaded'.

But I don't know what precisely to wire it to.
Ignoring the tachometer, thats pins 1, 4,5 all connected, and
2-3 over the armature. If you recall.

1 2 3 4 5 6 7
Purple White White White Red/Blue White White
-6,7 Armature Armature -1,5 -1,4 -7(1k6) -6 (1k6)
0V ~235V 0V 0 ~230V ~160V ~160V

Are you saying that this is the correct wiring [2 / 5] to live,
rest to neutral? But you believe the pulses may be too short
to actually do anything, even though it looks like loadsa
voltage?


You found the connections that go across the armature through the brushes,
so these are the only connections you need to make, to have the motor give a
spin. The test we do is with a modified connector, but it only has these
two connections made to the motor. The motor is actually single phase, so
the other connections are only to give signals to the controller unit from
the tachometer coil.

The tacho' coil is center tapped, so makes up two individual coils. One
wound one way around the holder. The second wound in the opposite
direction. When the magnet spins either way, it still produces the same
small signal to the controller. When the machine timer selects a full spin
state the two coils become one and as the magnet spins, the controller has
the full coil to check on to make sure the motor is up to full speed.

So you only need to make the connections to the motor on the two points that
pass through the brushes and the commutator on the armature. Remember to
hold the motor down with your foot, or another large heavy object, before
you plug in and switch on.

Hope this helps a bit more.

BigWallop wrote:

pedant
There's no such thing as centrifugal, it's centripetal force. As I
understand it centrifugal suggests that the centre of motion is
repelling something outwards where as really it's Newton's law.. Unless
a force is acted upon by another force it will continue in the same
direction, that is if something is flying round the centre of motion it
will keep flying outwards. Or something like that... Maybe you should
have a look on google.
/pedant

Regards,
Aaron.



And the heavy windings on the centre of the armature are actually trying to
fly outward away from the motor, so it's centrifugal force that's at work
here. :-)



Problem is I never got physics and sometimes I worried my physics
teacher didn't either :P. This is basically what we were taught in
A level physics, I never got it.

Maybe http://en.wikipedia.org/wiki/Centrifugal_force would be of
use. Especially the bit that says "In general, the force maintaining the
circular motion of an object is called the centripetal force."

--
Regards,
Aaron.

"Aaron" wrote in message
. uk...
BigWallop wrote:

pedant
There's no such thing as centrifugal, it's centripetal force. As I
understand it centrifugal suggests that the centre of motion is
repelling something outwards where as really it's Newton's law.. Unless
a force is acted upon by another force it will continue in the same
direction, that is if something is flying round the centre of motion it
will keep flying outwards. Or something like that... Maybe you should
have a look on google.
/pedant

Regards,
Aaron.



And the heavy windings on the centre of the armature are actually trying
to
fly outward away from the motor, so it's centrifugal force that's at
work
here. :-)



Problem is I never got physics and sometimes I worried my physics
teacher didn't either :P. This is basically what we were taught in
A level physics, I never got it.

Maybe http://en.wikipedia.org/wiki/Centrifugal_force would be of
use. Especially the bit that says "In general, the force maintaining the
circular motion of an object is called the centripetal force."

Regards,
Aaron.


You're right about your physics. Centripetal Force makes a mass drop inward
toward the centre. Centrifugal Force makes a mass fly off, away from the
centre. Like this explanation I found for you to look through.

**centripetal force and centrifugal force

centripetal force and centrifugal force, action-reaction force pair
associated with circular motion. According to Newton's first law of motion,
a moving body travels along a straight path with constant speed (i.e., has
constant velocity) unless it is acted on by an outside force. For circular
motion to occur there must be a constant force acting on a body, pushing it
toward the center of the circular path. This force is the centripetal
("center-seeking") force. For a planet orbiting the sun, the force is
gravitational; for an object twirled on a string, the force is mechanical;
for an electron orbiting an atom, it is electrical. The magnitude F of the
centripetal force is equal to the mass m of the body times its velocity
squared v 2 divided by the radius r of its path: F=mv2/r. According to
Newton's third law of motion, for every action there is an equal and
opposite reaction. The centripetal force, the action, is balanced by a
reaction force, the centrifugal ("center-fleeing") force. The two forces are
equal in magnitude and opposite in direction. The centrifugal force does not
act on the body in motion; the only force acting on the body in motion is
the centripetal force. The centrifugal force acts on the source of the
centripetal force to displace it radially from the center of the path. Thus,
in twirling a mass on a string, the centripetal force transmitted by the
string pulls in on the mass to keep it in its circular path, while the
centrifugal force transmitted by the string pulls outward on its point of
attachment at the center of the path. The centrifugal force is often
mistakenly thought to cause a body to fly out of its circular path when it
is released; rather, it is the removal of the centripetal force that allows
the body to travel in a straight line as required by Newton's first law. If
there were in fact a force acting to force the body out of its circular
path, its path when released would not be the straight tangential course
that is always observed.**