solenoids hot
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Posts: 46,084
you will have to measure the coil resistence firt wile
cold on a new one then the ones you are working with
now as the windings heat up insulation melts
the coil will start shorting layer at a time all
depends on the insulation on the coil wires the
resistence check will let you know if you have a
problem good luck
--- "[noparse][[/noparse].........................................]"
<manwithapipe@y...> wrote:
> I'm working with a BS2, an I/O Module rack , & a
> 12VDC/6A power supply
> for eight 10.5VDC 29-Ohm intermittent tubular pull
> solenoids (whew!).
> They are each spending around 30% of their time
> active. I realize
> that this is a lot of time for intermittent
> solenoids, but it's an
> availability and size issue.
>
> Aside from that, during extended periods of testing
> (more than and
> hour or two) the solenoids heat up quite a bit. How
> hot is TOO hot
> with standard solenoids? Also, what are the
> repercussions of heat and
> is there an effective way to dissipate heat?
>
>
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cold on a new one then the ones you are working with
now as the windings heat up insulation melts
the coil will start shorting layer at a time all
depends on the insulation on the coil wires the
resistence check will let you know if you have a
problem good luck
--- "[noparse][[/noparse].........................................]"
<manwithapipe@y...> wrote:
> I'm working with a BS2, an I/O Module rack , & a
> 12VDC/6A power supply
> for eight 10.5VDC 29-Ohm intermittent tubular pull
> solenoids (whew!).
> They are each spending around 30% of their time
> active. I realize
> that this is a lot of time for intermittent
> solenoids, but it's an
> availability and size issue.
>
> Aside from that, during extended periods of testing
> (more than and
> hour or two) the solenoids heat up quite a bit. How
> hot is TOO hot
> with standard solenoids? Also, what are the
> repercussions of heat and
> is there an effective way to dissipate heat?
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed.
> Text in the Subject and Body of the message will be
> ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
__________________________________
Do you Yahoo!?
Yahoo! SiteBuilder - Free, easy-to-use web site design software
http://sitebuilder.yahoo.com
Comments
solenoids use to stay on.
Find what the minimum activation voltage is. Sometimes they will work
at say 9 VDC. What application that they are used in will also
determind how much power you will need to activate the solenoid.
Once the solenoid is on you can reduce the power required by PWM the
drive signal to reduce the amound of power going to the solenoids.
Sometimes you can get by with a 50% duty cycle to maintain the state
of the solenoid.
Add a fan blowing across the solenoids when they are active.
Jason
> > Aside from that, during extended periods of testing
> > (more than and
> > hour or two) the solenoids heat up quite a bit. How
> > hot is TOO hot
> > with standard solenoids? Also, what are the
> > repercussions of heat and
> > is there an effective way to dissipate heat?
> >
Everyone has a different opinion on 'Too Hot'
Most solenoids will run warm to the touch. If it is too hot to grab hold of
comfortably then it is most likely too hot.
The manufacturer's spec sheet will give Max operating temps.
Cooling the unit with a fan will help, but the core will heat up the most,
where the least cooling air will flow by, none. If the heat cant get out of the
core fast enough then you will still do damage. Most coils are not designed
for this type of heating.
As for intermittent duty, the spec sheet will also describe this as duty
cycle or on/off cycles versus time.
Mother nature does not care if you are rich or poor, if you exceed the
ratings the device will fail prematurely. And Murphy is related to Mother
Nature..It
will fail at the worst possible moment.
Figure the cost of continuous duty solenoids Vs the cost of failure of the
ones you are using.
Will equipment be damaged?
Loss of income from a piece of non functioning machinery?
Embarrassment when your Scrub-A-Dub Laser Light Show malfunctions?
Hope this helps,
Alan Bradford
Plasma Technologies
In a message dated 7/21/2003 10:05:46 PM Eastern Daylight Time,
manwithapipe@y... writes:
>
> I'm working with a BS2, an I/O Module rack , &a 12VDC/6A power supply
> for eight 10.5VDC 29-Ohm intermittent tubular pull solenoids (whew!).
> They are each spending around 30% of their time active. I realize
> that this is a lot of time for intermittent solenoids, but it's an
> availability and size issue.
>
> Aside from that, during extended periods of testing (more than and
> hour or two) the solenoids heat up quite a bit. How hot is TOO hot
> with standard solenoids? Also, what are the repercussions of heat and
> is there an effective way to dissipate heat?
[noparse][[/noparse]Non-text portions of this message have been removed]
As to how hot? I would say to the point where insulation breakdown or
distortion become a problem. Insulation eventually will breakdown if design
parameters are exceded, so be sure to protect the drive circuitry from
failure due to short circuits. It seems you are trading reliability for
availability so you just need to expect a greater frequency of replacement
than ideal. As to effective ways to dissipate heat; simplest way is of
course to provide air flow over the solenoid bodies. Since you are powering
this device using an AC supply, add a fan to blow air across the solenoids.
If you mount the solenoids with aluminum brackets, some heat will transfer
to them and their surface area exposed to the air flow will help dissipate
some heat. Use thermal grease to enhance heat transfer. You may also find
that the holding current required on a solenoid is less than the current
required to active the solenoid and with better electronic controls, you may
limit current in that condition and not generate as much heat in the first
place. Usually a two level control is commonly used with a pulsed higher
voltage to activate and a holding level below that. A crude but simple way
to achieve this function is mearly to discharge a capacitor to activate and
apply a lower fixed level to hold.
good luck,
jim
http://www.geocities.com/jimforkin2003/
Original Message
From: [noparse][[/noparse].........................................]
[noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=aqhS49l5PA7JxmGW2zm8l8hv9RVbw8wmKCMi6GON0iiShPucSf5_G3KPk2bxUtUdDfrnXES7wo5WJZbOkg]manwithapipe@y...[/url
Sent: Monday, July 21, 2003 10:04 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] solenoids hot
I'm working with a BS2, an I/O Module rack , & a 12VDC/6A power supply
for eight 10.5VDC 29-Ohm intermittent tubular pull solenoids (whew!).
They are each spending around 30% of their time active. I realize
that this is a lot of time for intermittent solenoids, but it's an
availability and size issue.
Aside from that, during extended periods of testing (more than and
hour or two) the solenoids heat up quite a bit. How hot is TOO hot
with standard solenoids? Also, what are the repercussions of heat and
is there an effective way to dissipate heat?
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
Stepper motors, similar coils, different application.
but some stepper motors are spec'd to run 180 C ! lemme say that is
HOT !
But it does sound like you have enough power to add one of those
small CPU colling fans and not worry. I caution the reliance on
such a device. the fan fails, the units overheat (if they are out of
spec) and you have problems.
Dave
--- In
basicstamps@yahoogroups.com, "[noparse][[/noparse].......................................
..]" <manwithapipe@y...> wrote:
> I'm working with a BS2, an I/O Module rack , & a 12VDC/6A power
supply
> for eight 10.5VDC 29-Ohm intermittent tubular pull solenoids
(whew!).
> They are each spending around 30% of their time active. I realize
> that this is a lot of time for intermittent solenoids, but it's an
> availability and size issue.
>
> Aside from that, during extended periods of testing (more than and
> hour or two) the solenoids heat up quite a bit. How hot is TOO hot
> with standard solenoids? Also, what are the repercussions of heat
and
> is there an effective way to dissipate heat?
Regarding most electronic and electromechanical
devices, I always make the determination by hand. If
it is too hot to hold my finger on it for two seconds,
I seek alternative cooling sources. If you can keep
your finger on the part in questions for more than two
seconds comfortably, then it will probably survive a
long time. If not, you should consider fan cooling, a
heatsink, or a mounting method that conducts heat from
the hot part. I've built devices that last for decades
using this method. Follow datasheets, of course, but
this also seems to work.
Dr. Diode
--- Jim Forkin <jjf@p...> wrote:
> You asked about solenoids; As a general rule
> solenoids do run hot normally.
> As to how hot? I would say to the point where
> insulation breakdown or
> distortion become a problem. Insulation eventually
> will breakdown if design
> parameters are exceded, so be sure to protect the
> drive circuitry from
> failure due to short circuits. It seems you are
> trading reliability for
> availability so you just need to expect a greater
> frequency of replacement
> than ideal. As to effective ways to dissipate heat;
> simplest way is of
> course to provide air flow over the solenoid bodies.
> Since you are powering
> this device using an AC supply, add a fan to blow
> air across the solenoids.
> If you mount the solenoids with aluminum brackets,
> some heat will transfer
> to them and their surface area exposed to the air
> flow will help dissipate
> some heat. Use thermal grease to enhance heat
> transfer. You may also find
> that the holding current required on a solenoid is
> less than the current
> required to active the solenoid and with better
> electronic controls, you may
> limit current in that condition and not generate as
> much heat in the first
> place. Usually a two level control is commonly used
> with a pulsed higher
> voltage to activate and a holding level below that.
> A crude but simple way
> to achieve this function is mearly to discharge a
> capacitor to activate and
> apply a lower fixed level to hold.
>
> good luck,
>
> jim
> http://www.geocities.com/jimforkin2003/
>
>
>
Original Message
> From: [noparse][[/noparse].........................................]
> [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=f0xB7k89GiTSiYBncOG1-LbknYjhYg2s4KLpvBDqMzV4H9SjLlxvMj6I8ivYv-oVYEVUFWAU6JqrpCWDL5HM]manwithapipe@y...[/url
> Sent: Monday, July 21, 2003 10:04 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] solenoids hot
>
>
> I'm working with a BS2, an I/O Module rack , & a
> 12VDC/6A power supply
> for eight 10.5VDC 29-Ohm intermittent tubular pull
> solenoids (whew!).
> They are each spending around 30% of their time
> active. I realize
> that this is a lot of time for intermittent
> solenoids, but it's an
> availability and size issue.
>
> Aside from that, during extended periods of testing
> (more than and
> hour or two) the solenoids heat up quite a bit. How
> hot is TOO hot
> with standard solenoids? Also, what are the
> repercussions of heat and
> is there an effective way to dissipate heat?
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed.
> Text in the Subject and
> Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed.
> Text in the Subject and Body of the message will be
> ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
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microcontrollers. These were 24 Volt solenoids. We put a 12 volt
automobile tail lamp in series with the solenoid. When the lamp is
cold, it has a low resistance which gives the solenoid the current it
needs to pull in, Once energized, the lamp lit to full brilliance, its
resistance went up such that about 12 volts was dropped across each item
in series.
Best suggestion I've heard so far is to feed it with a 50% duty cycle
square wave once activated, if you can live with or filter the RFI that
this may generate.
Jim Forkin wrote:
[noparse][[/noparse]and BR snipped and edited]
> A crude but simple way
> to achieve this function is mearly to discharge a capacitor to activate and
> apply a lower fixed level to hold.
what type of solenoid are you using, is it designed for your project or did
you just find one and use it there are solenoids for ac and dc use the wrong
source and you will get heat. If the solenoid is actuating something and not
coming to its full throw it will get hot. some of the things I found is that
intermittent and continuous are the same solenoids, BUT with different
voltage ratings ex a 9vdc solenoid continuous may be the same as a 24vdc
intermittent duty they will give you the duty cycle in the spec sheet, there
are so many more things that could make the solenoid hot you will need to
look it up and size it correctly. Then it could be you! there is always
someone who says its too hot and the person next to them is saying its too
cold, get the spec sheet and measure the temp compare it to the operating
temp of the unit I have sites for solenoids (tubular types mostly ).
Larry Gaminde
Original Message
From: "Bob Reite" <bobr@t...>
To: <basicstamps@yahoogroups.com>
Sent: July 23, 2003 12:17 AM
Subject: Re: [noparse][[/noparse]basicstamps] solenoids hot
> We had a similar problems with hot solenoids back in the old days before
> microcontrollers. These were 24 Volt solenoids. We put a 12 volt
> automobile tail lamp in series with the solenoid. When the lamp is
> cold, it has a low resistance which gives the solenoid the current it
> needs to pull in, Once energized, the lamp lit to full brilliance, its
> resistance went up such that about 12 volts was dropped across each item
> in series.
>
> Best suggestion I've heard so far is to feed it with a 50% duty cycle
> square wave once activated, if you can live with or filter the RFI that
> this may generate.
>
>
> Jim Forkin wrote:
>
> [noparse][[/noparse]and BR snipped and edited]
> > A crude but simple way
> > to achieve this function is mearly to discharge a capacitor to activate
and
> > apply a lower fixed level to hold.
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>