On 3/13/23 12:15, Todd Zuercher wrote:
The wrong VFD settings can cause an overheat due to overcurrent. Were you
running the spindle at lower RPMs? Router spindles generally don't like
running at speeds less than 6000rpm, especially if the VFD settings aren’t
right. The VFD needs to be set so that it reduces the voltage applied with
reduced frequency. If this volt/hz reduction curve isn't right, either you can
over current and overheat the motor at lower speeds, or if set too low you lose
what little torque the spindle has. To know what these settings need to be set
to you need to know the motor's rated speed and voltage at those speeds and
current ratings. If the spindle manufacturer didn't supply a midrange voltage
setting, you may need to find that setting experimentally.
There is a much friendlier method Todd. Looking at the motors nameplate,
find the FLA rating, also known as Full Load Amps.
This is normally as you read any one phase.
For elderly 3 phase, 4 pole motors, setting whatever register controls
the low speed boost, to limit the boost applied to this FLA rating is I
believe the correct way to do that.
I have a 1 horse motor on my Sheldon 11x54, And I have the min speed
register set to 5 hz, I can do a 30 minute job at 5hz, and still lay my
hand on the motor at the end of that 30 minutes. That is at least a 60
year old motor, fairly high inductance so the coil currant is choked off
badly as the hz rises, by 180hz the 3.9 amp FLA isn't effected, because
the coil current is down to around an amp, all the vfd can do at the 250
VAC src voltage available. I haven't found need for the backgear, or a
belt change from 1st gear in years, the vfd does it all. Whisper quiet
too. Coil currant is so low that slip angle rises faster, so while I can
do 400 hz with that generic vfd, spindle speed actually falls above 200
hz. No torque either. Easily stalled, while the motor remains cold.
Sometimes it takes a careful read of the chinglish manual supplied with
the clone vfd's. And lock that manual up in the same safe you keep
accounts receivable in, cuz you're not going to be able to replace it 5
years from now.
My water cooled 4k motor on the 6040 has been tuned the same way, and it
will run down to about 2k revs indefinitely. It will of coarse warm up
the water tank but seems to stabilize in the middle 30's C.
That said, high speed spindle bearings can be failing and the spindle still
spin mostly freely by hand, but the spindle will be loud at speed due to
vibration and will overheat if run for extended periods of time at speed. A
high speed spindle should be very quiet at speed (not sound like a conventional
router motor.) Check for any slightest notchy-ness, when turning the spindle by
hand. It is often more cost-effective to have a loud spindle rebuilt before it
totally fails, than to run it till it won’t run anymore and then try to rebuilt
it or have to replace it because damage to the spindle is too severe.
What are your spindle motor’s rated speed, voltage and current? What do you
have the VFD set up for minimum, maximum, base and mid-range voltages, and
frequencies? Yes, those are 8 separate settings that most VFDs need to have
configured to run a high speed spindle correctly. Unfortunately many times the
spindle manufacture will only provide you with the spindle’s rated frequency
and voltage (use this for the “Base” frequency and voltage in the VFD) and the
maximum frequency and maybe voltage. If you are lucky and the spindle
manufacture provided you with some numbers to use for the mid-range settings if
so, use them. They may not be called that, it might just look like a low or
minimum speed setting with a reduced voltage (might be 5-7k rpm). If you don’t
have a recommendation from the spindle manufacture, experiment with different
mid-range voltage settings to find one that keeps the VFD’s current output
safely below the spindles rated continuous current.
For example I was just working at replacing a VFD for an HSD spindle that had
recommendations for 7k rpm @ 220v for the mid-range, but I also had to set the
minimum frequency and voltage to 0.5Hz and 1.0v, to prevent the motor from
occasionally stalling on acceleration when starting from stopped. When those
settings were incorrect the drive would overcurrent and shut down. When they
were close but not quite right the drive would run at high current and not
always accelerate correctly (stalling). With them correct the drive
accelerates the spindle quickly and only shows peak currents of about 15amps
while doing it.
PS I meant to send this last week, but forgot to click send, so it sat on my
work computer till this morning.
Todd Zuercher
P. Graham Dunn Inc.
630 Henry Street
Dalton, Ohio 44618
Phone: (330)828-2105ext. 2031
-----Original Message-----
From: Leonardo Marsaglia <ldmarsag...@gmail.com>
Sent: Wednesday, March 08, 2023 9:20 AM
To: Enhanced Machine Controller (EMC) <emc-users@lists.sourceforge.net>
Subject: Re: [Emc-users] OT: Air cooled router spindle problem
[EXTERNAL EMAIL] Be sure links are safe.
In fact, the day the rotor slipped, when the spindle cooled down a bit, it
started to work ok until I had the problem again. What I'm mostly worried about
is, if this was caused due to an overheat, why did that overheat occur in the
first place?
El mié, 8 mar 2023 a las 11:17, Leonardo Marsaglia (<ldmarsag...@gmail.com>)
escribió:
Most high speed spindles (such as router spindles) are rather
particular
about how the VFD is configured because of their low inductance.
What are your settings for base frequency and voltage? You may need
to adjust the settings for midrange frequency and voltage. What
these settings will do is adjust the volts/hertz curve to help keep
the motor from overcurrent when running at lower RPMs, and help
prevent stalls/excessive slippage on acceleration. These settings
usually need to be significantly different from most VFD's default
setting (which are usually configured for a 60hz
motor.)
Hi Todd,
I'll take a look and attach my settings as soon as possible for you to
see. But this setup was working well until the extreme heat days started.
Could it be that the ambient temperature (40ºC or more) could have
made the rotor slip effect worse? Maybe I was on the limit before and
the extreme heat conditions triggered the effect?
Thank you!
El mié, 8 mar 2023 a las 10:57, Todd Zuercher
(<to...@pgrahamdunn.com>)
escribió:
Most high speed spindles (such as router spindles) are rather
particular about how the VFD is configured because of their low
inductance. What are your settings for base frequency and voltage?
You may need to adjust the settings for midrange frequency and
voltage. What these settings will do is adjust the volts/hertz curve
to help keep the motor from overcurrent when running at lower RPMs,
and help prevent stalls/excessive slippage on acceleration. These
settings usually need to be significantly different from most VFD's
default setting (which are usually configured for a 60hz
motor.)
Todd Zuercher
P. Graham Dunn Inc.
630 Henry Street
Dalton, Ohio 44618
Phone: (330)828-2105ext. 2031
-----Original Message-----
From: Leonardo Marsaglia <ldmarsag...@gmail.com>
Sent: Tuesday, March 07, 2023 10:05 PM
To: Enhanced Machine Controller (EMC)
<emc-users@lists.sourceforge.net>
Subject: Re: [Emc-users] OT: Air cooled router spindle problem
[EXTERNAL EMAIL] Be sure links are safe.
Well, I tested it for almost an hour with no load at 15000 RPM and
the temperature settled at 55ºC in the bottom side where the bearings
for the tool holder are, and almost 65º in the body part where the stator is.
According to one of the Chinese suppliers of these spindles, 75ºC
it's a pretty common working temperature. I'm still waiting for a
detailed answer from the factory. This time, the VFD worked fine, no
whining with no rotor spin. Now I need to cut some wood while
monitoring the temperature during the process and hope the temperature doesn't
go too high.
Anyway, I'm looking for new VFD drives just in case. From what I can
tell the problem could be the VFD as Gene and Jon pointed out.
I'll let you know how it goes when cutting wood again.
Thanks to all for your help! :)
El dom, 5 mar 2023 a las 18:11, gene heskett (<ghesk...@shentel.net>)
escribió:
On 3/5/23 12:59, Leonardo Marsaglia wrote:
By the way, one subtle thing I noticed too that leads me to the
bearings
as
a problem.
Normally when the spindle is off and the dust removal vacuum
system is working, the spindle tends to spin by itself because of
the vacuum action on the impeller I installed. This almost never
happened yesterday. So, to sum up: I was able to free turn the
spindle by hand at all times, but the vacuum was not always able
to make it spin the impeller and if it did it wasn't nearly as
fast as days before. This is what makes me suspect about the
bearings. Also, almost all the problems I experienced yesterday
were with cutting forces involved, never with the spindle turning
free. Could
it
be that the extra heat and torque that's building up because of a
damaged bearing is what's making the VFD triggering for overcurrent?
What puzzles me still is when the spindle was too hot and with no
load
the
VFD only whined and couldn't make the spindle turn. This, as Jon
pointed out, recovered on its own a few minutes later.
I'll be there doing some tests in a few hours so I'll let you
know if I
can
note anything new.
Again a lot of thanks to you guys for being so kind and helpful!
:)
El sáb, 4 mar 2023 a las 15:51, Leonardo Marsaglia (<
ldmarsag...@gmail.com>)
escribió:
Hi guys.
Sorry for the OT but I'm having a strange behavior with my
spindle and
I'm
a little worried.
The problem I had today for the first time is the spindle was
getting really hot and started to slip (you could hear the
frequency from the inverter was on spot but the rotor sometimes
wasn't even turning).After
a
few seconds of slipping the VFD triggered the over current alarm
and the spindle was stopped. Once the the spindle cooled down it
worked
perfectly.
This never happened before but also I must clarify that today
the
ambient
temperature reached 40⁰C and I'm sure that under that roof where
the
router
is placed there were 45⁰C so I suspect this has something to do
with the problem.
The spindle is rated 11kw of max power output and is air cooled.
It has
a
built in fan motor so it doesn't rely on spindle speed for cooling.
It always gets warm (there are several labels on the spindle’s
body for caution because of the heat) but nothing like today.
Could this be normal because of the extremely hot days I'm
having
here?
Should I think about changing bearings or even rewind the motor?
I've
only
had the over current alarms when the spindle was too hot.
I will be really thankful if you can share your thoughts about this.
I think I'd want to look at the solder joints on the big capacitors
in the vfd, keeping in mind that they can hold quite a charge for
quite a while when turned off, and that is definitely a lethal
voltage. When I said look, I'm looking with an old camera lens for
a magnifying glass, checking for hairline cracks in the solder,
particularly at the edge of the solder puddle where the copper foil
begins, that is a favorite place for some seemingly crazy thermal
effects. And you can't just scrape it down to clean copper & bridge
it with solder, you must bridge the crack with a piece of suitable
gauge copper wire when patching such. And for future crack
development protection, a 2% silver bearing solder is much stronger than the
usual eutectic mix.
Same inspection comments apply to the semi's soldered joints, heat
sinks can exert joint breaking forces as they heat. I have a
couple of old 16mm projector lenses that get me up close and personal views.
An rch looks like a saw log to them.
Thanks for your help as always!
Leonardo.
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%252>
Fli%2F&data=05%7C01%7Ctoddz%40pgrahamdunn.com%7Ca716ced2cd8b45443
b1208db1fe039ab%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C6381
38820129481532%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIj
oiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=rj
6R%2BZb94rpPdzr%2F32kOery9rQ%2Ft47LLFaSdSWYo5h4%3D&reserved=0
sts.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=05%7C01%7
Cto
ddz%40pgrahamdunn.com%7C7c75dca8021a427b281508db1f821107%7C575854
4c5
73f47cebee96c3e0806fb43%7C0%7C0%7C638138415730530106%7CUnknown%7C
TWF
pbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJX
VCI
6Mn0%3D%7C3000%7C%7C%7C&sdata=s1%2FMmGIe%2BOIgMMj1IgKv6OTsDFxMuEk
7ms
t4mMsD%2FGE%3D&reserved=0
Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law
respectable.
- Louis D. Brandeis
Genes Web page
<https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fg
ene%2F&data=05%7C01%7Ctoddz%40pgrahamdunn.com%7Ca716ced2cd8b45443b1
208db1fe039ab%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C63813882
0129481532%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2lu
MzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=qogBfXcZjM
79r1NazIK82mCzsnrm4jJaRwbSLdvvPMg%3D&reserved=0
slinuxbox.net%3A6309%2F&data=05%7C01%7Ctoddz%40pgrahamdunn.com%7C7c
75d
ca8021a427b281508db1f821107%7C5758544c573f47cebee96c3e0806fb43%7C0%
7C0
%7C638138415730530106%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiL
CJQ
IjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=3X
tFc wOSBSFmFW5t2k9Bzfka64mLqLY4LnhinVrTrWY%3D&reserved=0>
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fl
ist%2F&data=05%7C01%7Ctoddz%40pgrahamdunn.com%7Ca716ced2cd8b45443b1
208db1fe039ab%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C63813882
0129481532%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2lu
MzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=dAuIKCeZqg
NHtCWkxG4a%2Bi7p332%2FkPW%2FQNlxo85am7o%3D&reserved=0
s.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=05%7C01%7Ctod
dz%
40pgrahamdunn.com%7C7c75dca8021a427b281508db1f821107%7C5758544c573f
47c
ebee96c3e0806fb43%7C0%7C0%7C638138415730530106%7CUnknown%7CTWFpbGZs
b3d
8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D
%7C
3000%7C%7C%7C&sdata=s1%2FMmGIe%2BOIgMMj1IgKv6OTsDFxMuEk7mst4mMsD%2F
GE%
3D&reserved=0
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Flis
ts.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=05%7C01%7Ctodd
z%40pgrahamdunn.com%7Ca716ced2cd8b45443b1208db1fe039ab%7C5758544c573f
47cebee96c3e0806fb43%7C0%7C0%7C638138820129481532%7CUnknown%7CTWFpbGZ
sb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%
3D%7C3000%7C%7C%7C&sdata=WUmFbAPwypt9tfFngQOn0ADiTlgp1bXQ7IFg5dmHEL0%
3D&reserved=0
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Flis
ts.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=05%7C01%7Ctodd
z%40pgrahamdunn.com%7Ca716ced2cd8b45443b1208db1fe039ab%7C5758544c573f
47cebee96c3e0806fb43%7C0%7C0%7C638138820129481532%7CUnknown%7CTWFpbGZ
sb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%
3D%7C3000%7C%7C%7C&sdata=WUmFbAPwypt9tfFngQOn0ADiTlgp1bXQ7IFg5dmHEL0%
3D&reserved=0
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=05%7C01%7Ctoddz%40pgrahamdunn.com%7Ca716ced2cd8b45443b1208db1fe039ab%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C638138820129481532%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=WUmFbAPwypt9tfFngQOn0ADiTlgp1bXQ7IFg5dmHEL0%3D&reserved=0
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users
Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users
