A neighbor has a Festool shop vac, er ... "dust extractor" (at $650, it
wouldn't sell as a "shop vac" G).

It has been shutting itself off due to the motor overheating. It's
spec'ed as using 2.9 - 8.3A (depending upon the speed, I assume). So I
put an ammeter on it and measured 9A, at low speed! Ah-ha, something to
work with. Suspecting a blocked air path was putting an extra load on
it, I first removed the dust bag, then the HEPA filter, and then took
the motor-fan out of the housing. No help: in free air, at low speed it
used 7.4A and at high speed 10A!

The rotor turns easily enough, but doesn't spin when given a push. The
brushes are fine and there is no arcing at the commutator.

So, the only thing that _might_ be an abnormality is the less-than-free
rotor. Could that be the basis for such increased current (7.5 vs 2.9)?
The assembly is not meant to be serviced (they'll sell you a new
motor-fan for $95+). I suppose that I don't have anything to lose by
trying to break it down, but I'd like there to be something else to try.

Any ideas?

Thanks,
Bob

"Bob Engelhardt" wrote in message
...
A neighbor has a Festool shop vac, er ... "dust extractor" (at $650,
it wouldn't sell as a "shop vac" G).

It has been shutting itself off due to the motor overheating. It's
spec'ed as using 2.9 - 8.3A (depending upon the speed, I assume).
So I put an ammeter on it and measured 9A, at low speed! Ah-ha,
something to work with. Suspecting a blocked air path was putting
an extra load on it, I first removed the dust bag, then the HEPA
filter, and then took the motor-fan out of the housing. No help: in
free air, at low speed it used 7.4A and at high speed 10A!

The rotor turns easily enough, but doesn't spin when given a push.
The brushes are fine and there is no arcing at the commutator.

So, the only thing that _might_ be an abnormality is the
less-than-free rotor. Could that be the basis for such increased
current (7.5 vs 2.9)? The assembly is not meant to be serviced
(they'll sell you a new motor-fan for $95+). I suppose that I don't
have anything to lose by trying to break it down, but I'd like there
to be something else to try.

Any ideas?

Thanks,
Bob

http://www.tpub.com/basae/28.htm

On Tue, 28 Apr 2015 19:51:06 -0400, Bob Engelhardt wrote:

A neighbor has a Festool shop vac, er ... "dust extractor" (at $650, it
wouldn't sell as a "shop vac" G).

It has been shutting itself off due to the motor overheating. It's
spec'ed as using 2.9 - 8.3A (depending upon the speed, I assume). So I
put an ammeter on it and measured 9A, at low speed! Ah-ha, something to
work with. Suspecting a blocked air path was putting an extra load on
it, I first removed the dust bag, then the HEPA filter, and then took
the motor-fan out of the housing. No help: in free air, at low speed it
used 7.4A and at high speed 10A!

The rotor turns easily enough, but doesn't spin when given a push. The
brushes are fine and there is no arcing at the commutator.

So, the only thing that _might_ be an abnormality is the less-than-free
rotor. Could that be the basis for such increased current (7.5 vs 2.9)?
The assembly is not meant to be serviced (they'll sell you a new
motor-fan for $95+). I suppose that I don't have anything to lose by
trying to break it down, but I'd like there to be something else to try.

I'm not sure of the exact mechanism, but on home-style vacuum cleaners
when you block the vacuum line the motor speeds up. I assume this means
the motor is unloaded, and I assume it's because the turbine is suddenly
working in rarefied air.

I'd be interested in hearing truth from one who knows.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

"Bob Engelhardt" wrote in message
...
...Suspecting a blocked air path was putting an extra load on it, I
first removed the dust bag, then the HEPA filter, and then took the
motor-fan out of the housing. No help: in free air, at low speed it
used 7.4A and at high speed 10A!

A blocked air path will -lower- the current because the fan blades
stall and give less lift and drag. Put your hand over the inlet of a
vacuum cleaner; the motor pitch rises.

On Tue, 28 Apr 2015 19:51:06 -0400, Bob Engelhardt
wrote:

A neighbor has a Festool shop vac, er ... "dust extractor" (at $650, it
wouldn't sell as a "shop vac" G).

It has been shutting itself off due to the motor overheating. It's
spec'ed as using 2.9 - 8.3A (depending upon the speed, I assume). So I
put an ammeter on it and measured 9A, at low speed! Ah-ha, something to
work with. Suspecting a blocked air path was putting an extra load on
it, I first removed the dust bag, then the HEPA filter, and then took
the motor-fan out of the housing. No help: in free air, at low speed it
used 7.4A and at high speed 10A!

The rotor turns easily enough, but doesn't spin when given a push. The
brushes are fine and there is no arcing at the commutator.

So, the only thing that _might_ be an abnormality is the less-than-free
rotor. Could that be the basis for such increased current (7.5 vs 2.9)?
The assembly is not meant to be serviced (they'll sell you a new
motor-fan for $95+). I suppose that I don't have anything to lose by
trying to break it down, but I'd like there to be something else to try.

Any ideas?

Thanks,
Bob

One thing to keep in mind is that the current draw of a centrifugal
blower will usually go down as its output is restricted. The current
is more closely related to the airflow than to the back pressure. So
it's not surprising that you saw an increase in current when you
removed all the restrictions.

--
Ned Simmons

Tim Wescott fired this volley in
:

I'd be interested in hearing truth from one who knows.

The speed is dependent upon the mass of air being moved. It's pretty
large when sucking and blowing freely. The motor does the most work
moving the largest volume. When the inlet is blocked, the fan just
recirculates the air in the volute, and it's (essentially) unloaded.

The air isn't 'rarified' enough to make a huge difference... most only
suck in a few tens of inches of water column... and it takes almost 34'
of water to make one atmosphere's worth of pressure.

Lloyd

On 4/28/2015 8:47 PM, Lloyd E. Sponenburgh wrote:

The speed [current?] is dependent upon the mass of air being moved. It's pretty
large when sucking and blowing freely. The motor does the most work
moving the largest volume. When the inlet is blocked, the fan just
recirculates the air in the volute, and it's (essentially) unloaded.
...

Oh, yeah ... I remember now, about the current increasing as restriction
decreases. Seems paradoxical until you think about it as a matter of
mass of air being moved. Thanks for that "model".

Now, back to the original problem: with the "extractor" operational, it
was overheating. The mass-of-air model would suggest that the cause of
that would be an air _leak_, not a blockage. I'll look into that & be back.

Thanks,
Bob

On 4/28/2015 8:07 PM, Jim Wilkins wrote:
http://www.tpub.com/basae/28.htm [rotor winding test]

I don't know how true this is, but I was assuming that a bad rotor would
cause sparking on the commutator and there is none.

On Tue, 28 Apr 2015 19:51:06 -0400, Bob Engelhardt
wrote:

A neighbor has a Festool shop vac, er ... "dust extractor" (at $650, it
wouldn't sell as a "shop vac" G).

It has been shutting itself off due to the motor overheating. It's
spec'ed as using 2.9 - 8.3A (depending upon the speed, I assume). So I
put an ammeter on it and measured 9A, at low speed! Ah-ha, something to
work with. Suspecting a blocked air path was putting an extra load on
it, I first removed the dust bag, then the HEPA filter, and then took
the motor-fan out of the housing. No help: in free air, at low speed it
used 7.4A and at high speed 10A!

The rotor turns easily enough, but doesn't spin when given a push. The
brushes are fine and there is no arcing at the commutator.

So, the only thing that _might_ be an abnormality is the less-than-free
rotor. Could that be the basis for such increased current (7.5 vs 2.9)?
The assembly is not meant to be serviced (they'll sell you a new
motor-fan for $95+). I suppose that I don't have anything to lose by
trying to break it down, but I'd like there to be something else to try.

Any ideas?

Thanks,
Bob

Stick the entire motor in a gallon can of kero or diesel or even WD-40
and see if the bearings/bushings will free up after soaking for over
night. But the bearings/bushings ARE the problem..so ask yourself
....can you replace them yourself? Or does he need to order a new
motor....?

On Tue, 28 Apr 2015 20:07:03 -0400, "Jim Wilkins"
wrote:

"Bob Engelhardt" wrote in message
...
A neighbor has a Festool shop vac, er ... "dust extractor" (at $650,
it wouldn't sell as a "shop vac" G).

It has been shutting itself off due to the motor overheating. It's
spec'ed as using 2.9 - 8.3A (depending upon the speed, I assume).
So I put an ammeter on it and measured 9A, at low speed! Ah-ha,
something to work with. Suspecting a blocked air path was putting
an extra load on it, I first removed the dust bag, then the HEPA
filter, and then took the motor-fan out of the housing. No help: in
free air, at low speed it used 7.4A and at high speed 10A!

The rotor turns easily enough, but doesn't spin when given a push.
The brushes are fine and there is no arcing at the commutator.

So, the only thing that _might_ be an abnormality is the
less-than-free rotor. Could that be the basis for such increased
current (7.5 vs 2.9)? The assembly is not meant to be serviced
(they'll sell you a new motor-fan for $95+). I suppose that I don't
have anything to lose by trying to break it down, but I'd like there
to be something else to try.

Any ideas?

Umm, give it back to Festool for a warranty replacement?
I think Festo is one of the companies who take warranties to a new
level. Given their outrageous pricing, I'm not surprised.

--
"I believe there are more instances of the abridgment of the freedom
of the people by gradual and silent encroachments of those in power
than by violent and sudden usurpations."
--James Madison, Virginia Convention, June 16, 1788

Gunner Asch fired this volley in
:

But the bearings/bushings ARE the problem..so ask yourself
...can you replace them yourself? Or does he need to order a new
motor....?


Gunner makes a good point. If the (I'll bet bushings) are even a little
snug when cold, you can bet they'll bind up when hot.

Lloyd

On 4/28/2015 10:09 PM, Larry Jaques wrote:
Umm, give it back to Festool for a warranty replacement?
I think Festo is one of the companies who take warranties to a new
level. Given their outrageous pricing, I'm not surprised.

Out of warranty. I have heard that they are very good at customer
service. As you said, they should be for the prices they charge.

Tim Wescott wrote:
On Tue, 28 Apr 2015 19:51:06 -0400, Bob Engelhardt wrote:

A neighbor has a Festool shop vac, er ... "dust extractor" (at $650, it
wouldn't sell as a "shop vac" G).

It has been shutting itself off due to the motor overheating. It's
spec'ed as using 2.9 - 8.3A (depending upon the speed, I assume). So I
put an ammeter on it and measured 9A, at low speed! Ah-ha, something to
work with. Suspecting a blocked air path was putting an extra load on
it, I first removed the dust bag, then the HEPA filter, and then took
the motor-fan out of the housing. No help: in free air, at low speed it
used 7.4A and at high speed 10A!

The rotor turns easily enough, but doesn't spin when given a push. The
brushes are fine and there is no arcing at the commutator.

So, the only thing that _might_ be an abnormality is the less-than-free
rotor. Could that be the basis for such increased current (7.5 vs 2.9)?
The assembly is not meant to be serviced (they'll sell you a new
motor-fan for $95+). I suppose that I don't have anything to lose by
trying to break it down, but I'd like there to be something else to try.

I'm not sure of the exact mechanism, but on home-style vacuum cleaners
when you block the vacuum line the motor speeds up. I assume this means
the motor is unloaded, and I assume it's because the turbine is suddenly
working in rarefied air.

I'd be interested in hearing truth from one who knows.


That is one way of looking at it. Normally the air is
very dense on the leading edge of the vanes when its
plugged it is more rarefied. Its kind of like when you
are rowing a canoe and you miss the water. Its a whole
lot easier when not pushing against something dense.

"Bob Engelhardt" wrote in message
...
On 4/28/2015 8:07 PM, Jim Wilkins wrote:
http://www.tpub.com/basae/28.htm [rotor winding test]

I don't know how true this is, but I was assuming that a bad rotor
would cause sparking on the commutator and there is none.


When I don't know what's wrong I perform the easy tests to narrow it
down. Often simply disassembling, cleaning and oiling everything fixes
it.

Here's a motor shop fairly close to you:
http://www.chelmsfordautoelectric.com/services.nxg

I worked in Lexington for a while but don't know the businesses around
there, or Concord.

-jsw

"jim" " wrote in message
...
Tim Wescott wrote:
On Tue, 28 Apr 2015 19:51:06 -0400, Bob Engelhardt wrote:

A neighbor has a Festool shop vac, er ... "dust extractor" (at
$650, it
wouldn't sell as a "shop vac" G).

It has been shutting itself off due to the motor overheating.
It's
spec'ed as using 2.9 - 8.3A (depending upon the speed, I assume).
So I
put an ammeter on it and measured 9A, at low speed! Ah-ha,
something to
work with. Suspecting a blocked air path was putting an extra
load on
it, I first removed the dust bag, then the HEPA filter, and then
took
the motor-fan out of the housing. No help: in free air, at low
speed it
used 7.4A and at high speed 10A!

The rotor turns easily enough, but doesn't spin when given a push.
The
brushes are fine and there is no arcing at the commutator.

So, the only thing that _might_ be an abnormality is the
less-than-free
rotor. Could that be the basis for such increased current (7.5 vs
2.9)?
The assembly is not meant to be serviced (they'll sell you a
new
motor-fan for $95+). I suppose that I don't have anything to lose
by
trying to break it down, but I'd like there to be something else
to try.

I'm not sure of the exact mechanism, but on home-style vacuum
cleaners
when you block the vacuum line the motor speeds up. I assume this
means
the motor is unloaded, and I assume it's because the turbine is
suddenly
working in rarefied air.

I'd be interested in hearing truth from one who knows.


That is one way of looking at it. Normally the air is
very dense on the leading edge of the vanes when its
plugged it is more rarefied. Its kind of like when you
are rowing a canoe and you miss the water. Its a whole
lot easier when not pushing against something dense.

You could see if there's a difference between blocking the inlet and
the outlet.

Jim Wilkins wrote:
"jim" " wrote in message
...
Tim Wescott wrote:
On Tue, 28 Apr 2015 19:51:06 -0400, Bob Engelhardt wrote:

A neighbor has a Festool shop vac, er ... "dust extractor" (at
$650, it
wouldn't sell as a "shop vac" G).

It has been shutting itself off due to the motor overheating.
It's
spec'ed as using 2.9 - 8.3A (depending upon the speed, I assume).
So I
put an ammeter on it and measured 9A, at low speed! Ah-ha,
something to
work with. Suspecting a blocked air path was putting an extra
load on
it, I first removed the dust bag, then the HEPA filter, and then
took
the motor-fan out of the housing. No help: in free air, at low
speed it
used 7.4A and at high speed 10A!

The rotor turns easily enough, but doesn't spin when given a push.
The
brushes are fine and there is no arcing at the commutator.

So, the only thing that _might_ be an abnormality is the
less-than-free
rotor. Could that be the basis for such increased current (7.5 vs
2.9)?
The assembly is not meant to be serviced (they'll sell you a
new
motor-fan for $95+). I suppose that I don't have anything to lose
by
trying to break it down, but I'd like there to be something else
to try.

I'm not sure of the exact mechanism, but on home-style vacuum
cleaners
when you block the vacuum line the motor speeds up. I assume this
means
the motor is unloaded, and I assume it's because the turbine is
suddenly
working in rarefied air.

I'd be interested in hearing truth from one who knows.


That is one way of looking at it. Normally the air is
very dense on the leading edge of the vanes when its
plugged it is more rarefied. Its kind of like when you
are rowing a canoe and you miss the water. Its a whole
lot easier when not pushing against something dense.

You could see if there's a difference between blocking the inlet and
the outlet.


Both will lower the load on the motor but not the same amount.
The load goes down when the pressure differential on either
side of the vane goes down. When the flow is blocked the air
just goes round and round and there is not much pressure
differential. When the inlet is blocked the air is more
rarefied so it does have slightly less resistance.

Also there is probably some air flow through the motor for cooling.
If that is on the discharge side blocking the discharge won't
stop all flow and blocking the inlet may still cause overheating
because the motor cooling flow is also stopped.

On Tue, 28 Apr 2015 21:46:38 -0400, Bob Engelhardt wrote:

On 4/28/2015 8:47 PM, Lloyd E. Sponenburgh wrote:

The speed [current?] is dependent upon the mass of air being moved.
It's pretty large when sucking and blowing freely. The motor does the
most work moving the largest volume. When the inlet is blocked, the fan
just recirculates the air in the volute, and it's (essentially)
unloaded.
...

Oh, yeah ... I remember now, about the current increasing as restriction
decreases. Seems paradoxical until you think about it as a matter of
mass of air being moved. Thanks for that "model".

Now, back to the original problem: with the "extractor" operational, it
was overheating. The mass-of-air model would suggest that the cause of
that would be an air _leak_, not a blockage. I'll look into that & be
back.

Either that or the excess friction in the motor -- it really ought to spin
more or less freely (taking bearing seals into account, which I doubt are
there).

I recall grabbing the shaft of a 10-horse compressor motor and (slowly)
giving it a spin -- I think that would be my baseline.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

On 04/28/2015 9:13 PM, Lloyd E. Sponenburgh wrote:
Gunner fired this volley in
:

But the bearings/bushings ARE the problem..so ask yourself
...can you replace them yourself? Or does he need to order a new
motor....?


Gunner makes a good point. If the (I'll bet bushings) are even a little
snug when cold, you can bet they'll bind up when hot.

If Festool is using only bushings in a $650 shop-vac, I'm _sure_ they're
more than just over-priced.

--

On 4/29/2015 12:34 PM, Tim Wescott wrote:
On Tue, 28 Apr 2015 21:46:38 -0400, Bob Engelhardt wrote:
....
Now, back to the original problem: with the "extractor" operational, it
was overheating. The mass-of-air model would suggest that the cause of
that would be an air _leak_, not a blockage. I'll look into that & be
back.


Either that or the excess friction in the motor -- it really ought to spin
more or less freely (taking bearing seals into account, which I doubt are
there).
...

OK: I put my hand over the intake of the fan, blocking it totally and
the current dropped some, from 7.4 to 5.6A. Still way above the spec'ed
minimum of 2.9. So the problem is not a leak. Meaning it must(?) be
bearings.

I'm going to try to do some cleaning without disassembly. Not Gunner's
total immersion, cause I'll use PB Blaster, some such, and I don't have
a gallon of that.

Bob

On 4/29/2015 1:13 PM, dpb wrote:
On 04/28/2015 9:13 PM, Lloyd E. Sponenburgh wrote:
Gunner fired this volley i

But the bearings/bushings ARE the problem..so ask yourself
...can you replace them yourself? Or does he need to order a new
motor....?


Gunner makes a good point. If the (I'll bet bushings) are even a little
snug when cold, you can bet they'll bind up when hot.


If Festool is using only bushings in a $650 shop-vac, I'm _sure_ they're
more than just over-priced.

I'm pretty sure that I read that it has bearings. Festool does not
consider them serviceable and sells the motor-fan for $95.

Bob

On Wed, 29 Apr 2015 15:31:09 -0400
Bob Engelhardt wrote:

snip
OK: I put my hand over the intake of the fan, blocking it totally and
the current dropped some, from 7.4 to 5.6A. Still way above the spec'ed
minimum of 2.9. So the problem is not a leak. Meaning it must(?) be
bearings.

I'm going to try to do some cleaning without disassembly. Not Gunner's
total immersion, cause I'll use PB Blaster, some such, and I don't have
a gallon of that.

How do they control the speed? i.e. can you check/get in between the
speed control and the actual motor?

Just wondering if something went bad in the speed control and it's
sinking the extra amperage. Do you have any kind of schematic to work
with that might show any of this?

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

On 4/29/2015 3:44 PM, Leon Fisk wrote:
How do they control the speed? i.e. can you check/get in between the
speed control and the actual motor?

Just wondering if something went bad in the speed control and it's
sinking the extra amperage. Do you have any kind of schematic to work
with that might show any of this?

There is a PC board for speed control. No schematic that I could find
on the net.

I had this thought too & I put a Fluke clamp-on true RMS meter between
the controller and the motor. It read the same as the ammeter on the input.

Bob

On Wed, 29 Apr 2015 18:24:03 -0400
Bob Engelhardt wrote:

snip
There is a PC board for speed control. No schematic that I could find
on the net.

I had this thought too & I put a Fluke clamp-on true RMS meter between
the controller and the motor. It read the same as the ammeter on the input.

I'm guessing that this is the model you're working on:

http://www.festoolusa.com/power-tool...tractor-583492

Per their website they list the amperage as "Power Consumption
350-1200 watts, 2.9-10.0 amps". Maybe the temperature sensing mechanism
is at fault and not the motor. Just saying...

Interestingly the manual:

http://www.festoolusa.com/media/pdf/...EPA_Manual.pdf

has the amperage as you said:

===
Power consumption (dust extractor only) 2.9 - 8.3 A (350 - 1000 W) see
note 1 .

Note 1: 8.3 A (1000 W) is the medium value for different operation
conditions, a maximum power consumption of 10 A (1200 W) is possible.
===

Different model comparison chart on this page along with amperage
values:

http://www.festoolusa.com/power-tool...st-extractors/

Any loose heat-sink items on the electronics board or something that
could mess up the temperature sensing?

One last thought after perusing the manual... Have you experienced the
unit overheating? From what I could deduce reading the manual:

===
Max. rating of connected Power Tool = 3.7 A - Note: When the suction
power adjuster [1-7] is adjusted to the lowest suction power (see page
10, chapter Settings - Adjusting the suction power) the maximal rating
of a connected power tool can be 9.1 Amps.
===

It doesn't say whether this load is being sensed by the over
temperature alarm but I think it might be. Did your neighbor have
something a bit too greedy plugged into it?

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

On 4/30/2015 10:32 AM, Leon Fisk wrote:
I'm guessing that this is the model you're working on:

http://www.festoolusa.com/power-tool...tractor-583492

Yes

... Maybe the temperature sensing mechanism
is at fault and not the motor.

I don't think so, because of the large currents that I am measuring.

....
Any loose heat-sink items on the electronics board or something that
could mess up the temperature sensing?

The temperature sensor is on the side of the motor. There could be
circuitry that reads it on the board, but I do believe that it does
overheat, from the currents I measure.

One last thought after perusing the manual... Have you experienced the
unit overheating? ...

No - I haven't let it run very long.

Max. rating of connected Power Tool = 3.7 A - Note: When the suction
power adjuster [1-7] is adjusted to the lowest suction power (see page
10, chapter Settings - Adjusting the suction power) the maximal rating
of a connected power tool can be 9.1 Amps.
===

It doesn't say whether this load is being sensed by the over
temperature alarm but I think it might be. Did your neighbor have
something a bit too greedy plugged into it?

The vac plus the connected load can't exceed 12A. Maybe the sensor on
the motor is a switch that interrupts both & its limit is 12A.

The neighbor has experienced shut-off with no connected load.

I've never felt very strongly that the bearings are the problem - they
just don't seem tight enough to cause that much draw (5.6A on low speed
vs 2.9 spec'ed). But it was the only thing that I thought of.

Another thing that I just thought of was damaged field winding. I.e.,
adjacent turns shorted, reducing the field, and drawing more current. I
don't know if that makes sense, if it ever happens, or how to test for it.

The motor-fan unit has fragile fans pressed on both ends, has a housing
that is glued or heat-welded together, and is just not going to be
explored. I'm about ready to pull the plug and have the neighbor order
a new one.

Bob

On Thu, 30 Apr 2015 19:51:40 -0400
Bob Engelhardt wrote:

snip
I've never felt very strongly that the bearings are the problem - they
just don't seem tight enough to cause that much draw (5.6A on low speed
vs 2.9 spec'ed). But it was the only thing that I thought of.

Have you got a scope that you could look at the waveform with? I've
been wondering right along how accurate your ampmeter is when measuring
this type of waveform. I know you said it was a Fluke with RMS but...

The manual mentions that too light of an extension cord could cause
problems. It also mentions that they make both 50 and 60 hz models. Any
chance it might be a 50 hz unit? Followed your neighbor in from some
foreign country maybe...

Harbor Freight has their Infrared Temperature Gun on sale right now
with coupon for $25.99. Just in case you are wondering how hot the motor
gets ;-)

http://widgets.harborfreight.com/wsw...l_s1021_c1815b

I bought one a while back, same price with coupon. It works okay,
nothing special. I wanted to measure how hot my front wheel hubs
were getting on my truck. Was afraid I might have a caliper dragging...

Used it for other odds and ends since then.

One of these days I'll tear it apart. Suspect it may be capable of
doing some other things too but doesn't have the switches or something.
The most annoying thing about it is the default is Centigrade readings.
You have to switch it to Fahrenheit every time you use it. Centigrade
is okay, but I just don't think that way...

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

On Fri, 1 May 2015 10:06:37 -0400, Leon Fisk
wrote:

On Thu, 30 Apr 2015 19:51:40 -0400
Bob Engelhardt wrote:

snip
I've never felt very strongly that the bearings are the problem - they
just don't seem tight enough to cause that much draw (5.6A on low speed
vs 2.9 spec'ed). But it was the only thing that I thought of.

Have you got a scope that you could look at the waveform with? I've
been wondering right along how accurate your ampmeter is when measuring
this type of waveform. I know you said it was a Fluke with RMS but...

The manual mentions that too light of an extension cord could cause
problems. It also mentions that they make both 50 and 60 hz models. Any
chance it might be a 50 hz unit? Followed your neighbor in from some
foreign country maybe...
A 50 hz unit will run fine on 60 - just a bit faster. Running a 60 on
50 will cause problems (or at least very likely would) %0 hz needs
more iron than 60.

Harbor Freight has their Infrared Temperature Gun on sale right now
with coupon for $25.99. Just in case you are wondering how hot the motor
gets ;-)

http://widgets.harborfreight.com/wsw...l_s1021_c1815b

I bought one a while back, same price with coupon. It works okay,
nothing special. I wanted to measure how hot my front wheel hubs
were getting on my truck. Was afraid I might have a caliper dragging...

Used it for other odds and ends since then.

One of these days I'll tear it apart. Suspect it may be capable of
doing some other things too but doesn't have the switches or something.
The most annoying thing about it is the default is Centigrade readings.
You have to switch it to Fahrenheit every time you use it. Centigrade
is okay, but I just don't think that way...