Driver to drive?

Am 19.03.2018 um 11:28 schrieb Castorp:
So, here's the device with popcorn noise in one of the channels:

http://nbeev.web.cern.ch/device1_psd.png
http://nbeev.web.cern.ch/device1_td.png

The second device is my own 89440 - the only one I have access to right now. Channel A is clearly better in terms of LF noise. The magenta curve is cross-spectrum.

http://nbeev.web.cern.ch/device2_psd_hf.png
http://nbeev.web.cern.ch/device2_psd_lf.png

All these measurements are on the finest range, 1MOhm inputs with external short, DC-coupled.

I coulnd't find the ADA4522-1 preamp measurement files, but I found notes on the setup. The preamp was followed by an SRS amplifier, and the total gain was 10000. That was enough to ensure flat floor down to a few mHz, but around there it did intersect with the 89440A 1/f noise. For my purposes back then it was fine.

All of the batteries I tested showed steeper than 1/f behaviour at low frequencies, so they were not good enough as a DC source for my tests. And I did it carefully - temperature-stabilized oven, no stress, mechanical relief, plenty of time to settle, etc...
Click to expand...

Hi, Nikolai,
thanks for the information.

I'm just plowing through the 89441A programming manual to upgrade
my control program. The manual leaves of lot of open questions,
the only thing they say again and again is that I cannot use
options that are not built-in.

regards,
Gerhard
 
On 20/03/2018 13:58, Ralph Mowery wrote:
In article <0radnSinAYWBEi3HnZ2dnUU78YudnZ2d@giganews.com>, void-
invalid-dead-dontuse@gmail.com says...

On 30/01/2018 20:56, oldschool@tubes.com wrote:
I have a GB Instruments multimeter (GMT -19A).
I've had this meter for years and it's always worked fine.

It came with 2 fuses. One was installed in the fuse holder inside by the
batteries. The other is a spare fuse which was in a plastic clip on the
other side of the batteries, and meant to be a spare.

The fuses are 7/8 inch long and are supposed to be SFE 0.5 amp / 250V.
...

WTF does SFE mean??

Society of Fuse Engineers

snip
Click to expand...

Definitely very sub-standard for this application then.

--

Brian Gregory (in England).
 
please send me that 'Principles of Electronic Materials and Devices, 4th Edition By Safa Kasap' solution. thank you so much.
 
On Saturday, 7 April 2018 04:24:47 UTC+1, olds...@tubes.com wrote:
I have a clip on light that I want to use temporarily for light in a
room I am redoing. The fixture has a dimmer on it, but I dont want to
dim it, just leave it on full brightness.

Can I use a non-dimming LED bulb on this fixture as long as it's left on
full brightness, or will the dimmer damage something just because it's
there?

I've never used a dimmer on LED bulbs, so I am not sure.
If it's a problem, I'll just use an incandescent bulb, since this is
only for a few days anyhow, until I get some permanent lights installed
in the room.

And just for the heck of knowing, what does happen if someone dims the
non-dimming LED bulbs?
Click to expand...

If it really stays on 100% full, no problem. If not
- if it's a CR psu, it'll fry rapidly.
- if it's a smpsu it'll either flicker or fry.


NT
 
On Friday, April 6, 2018 at 8:24:47 PM UTC-7, olds...@tubes.com wrote:
I have a clip on light that I want to use temporarily for light in a
room I am redoing. The fixture has a dimmer on it, but I dont want to
dim it, just leave it on full brightness.

Can I use a non-dimming LED bulb on this fixture as long as it's left on
full brightness
Click to expand...

Probably not. Two reasons: 'full' is maybe 90%, and there's an
abrupt turnon with dimmer switches that is absent with straight AC.
That puts (possibly) extra current through a capacitor dropper circuit,
which can burn out the LED power parts, after a few minutes, that ordinarily
would survive ONE abrupt turn-on.

Second reason: many dimmers expect a resistive load, and may misbehave in
connection with the LED, so 'full brightness' might not be possible for the
dimmer. Flicker is not an uncommon result; very annoying.
 
On Tuesday, November 7, 2017 at 7:16:36 PM UTC+1, Don Kuenz wrote:
The DC voltage on many (all?) ham radio power supplies tops out at
about 14VDC. So what do you do when you find the perfect relay, but it
only comes in the 24VDC or 28VDC pull-in flavor?
"Using Direct-Current Relays at Lower Coil Voltages" (KE0FF), in
the current issue of _QEX_, talks about how to use a boost capacitor to
kick start a relay using a voltage lower than the pull-in voltage, Vpi.
The circuit exploits the difference between Vpi and the typically much
smaller holding voltage, Vh. KE0FF's _QEX_ article builds on "How to
Operate 24V relays on 12V" (KO4BB) [1].
The operation of KO4BB's circuit (shown at the link) seems simple
enough. Be that as it may, allow me to "walk through" it for the sake of
thoroughness. Any constructive criticism or elaboration on your part is
encouraged.
Next to the coil is a snubber diode. When the switch is open, the
transistor's shut off and both relay poles are at a Vdd - 0.6V = V1
potential. The capacitor also charges to a V1 potential when the switch
is open.
When the switch is closed the transistor turns on and grounds the
lower pole of the coil. The top diode turns off while the bottom diode
free-wheels the cap and the top pole of the coil up to Vdd + V1. At this
point a Vdd + V1 potential is impressed against the relay's coil, which
causes the relay to close.
The whole trick is to keep enough potential impressed against the
coil long enough for Vh to come into play. At that point, as long as
Vdd is greater than Vh the relay will stay closed. The cap must be sized
to accommodate the timing constant from the coil's internal resistance.

Note.

1. http://www.ko4bb.com/ham_radio/Projects/24V_Relays/
Click to expand...

I have a relay that has a specified must operate voltage of 9V (12V relay, so 85% of nominal)

The holding voltage is lower than the must operate, since the must operate is for pulling in the armature. When the armature is pulled in, the magnetic path is lower, and thus needs less current to have the same force on the armature to withstand vibration etc

I do not have a holding spec, but I need it and would like to deduce it from the must operate voltage

So I was thinking about opening up the relay, and mouting it downwards, so i could place a weight on the armature, to measure precisely the force needed to keep the equilibrium state (no movement of the armature), both for the pulled-in case, and also for the released state, so I can calculate the needed holding voltage

(and yes, I have contacted Omron, but they can sofar not present Holding voltage specs)

I could also measure the inductance of the coil, in both pulled-in state and the released state, which also should give me the different in current to obtain the same magnetic field (magnetic path in pulled-in state is shorter)

Anyone got ideas?

Cheers

Klaus
 
SNIP
So I was thinking about opening up the relay, and mouting it downwards, so i could place a weight on the armature, to measure precisely the force needed to keep the equilibrium state (no movement of the armature), both for the pulled-in case, and also for the released state, so I can calculate the needed holding voltage

(and yes, I have contacted Omron, but they can sofar not present Holding voltage specs)

I could also measure the inductance of the coil, in both pulled-in state and the released state, which also should give me the different in current to obtain the same magnetic field (magnetic path in pulled-in state is shorter)

Anyone got ideas?

Cheers

Klaus
Click to expand...
Drive it with a variable voltage PSU ???? Start with 9V to operate, then
reduce the voltage until the relay drops out... then add some margin % ?
Seems simple to me.

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
 
TTman <kraken.sankey@gmail.com> wrote:
SNIP
So I was thinking about opening up the relay, and mouting it downwards,
so i could place a weight on the armature, to measure precisely the force
needed to keep the equilibrium state (no movement of the armature), both
for the pulled-in case, and also for the released state, so I can calculate
the needed holding voltage

(and yes, I have contacted Omron, but they can sofar not present Holding
voltage specs)

I could also measure the inductance of the coil, in both pulled-in state
and the released state, which also should give me the different in current
to obtain the same magnetic field (magnetic path in pulled-in state is shorter)

Anyone got ideas?

Drive it with a variable voltage PSU ???? Start with 9V to operate, then
reduce the voltage until the relay drops out... then add some margin % ?
Seems simple to me.
Click to expand...

Your procedure gives the undisturbed value of Vh. If you lack the
equipment to introduce temperature and vibration stimuli, the margin %
must be estimated. The QEX author, KE0FF, believes that if the
undisturbed Vh is lower than 75% of the rated coil voltage value, then
the relay ought to reliably hold in the engaged position.

Thank you,

--
Don Kuenz, KB7RPU
 
On Monday, April 16, 2018 at 2:47:11 PM UTC+2, TTman wrote:
SNIP
So I was thinking about opening up the relay, and mouting it downwards, so i could place a weight on the armature, to measure precisely the force needed to keep the equilibrium state (no movement of the armature), both for the pulled-in case, and also for the released state, so I can calculate the needed holding voltage

(and yes, I have contacted Omron, but they can sofar not present Holding voltage specs)

I could also measure the inductance of the coil, in both pulled-in state and the released state, which also should give me the different in current to obtain the same magnetic field (magnetic path in pulled-in state is shorter)

Anyone got ideas?

Cheers

Klaus

Drive it with a variable voltage PSU ???? Start with 9V to operate, then
reduce the voltage until the relay drops out... then add some margin % ?
Seems simple to me.

I know how to do that, but I need the robustness margin for vibration etc to be valid
Click to expand...

Cheers

Klaus
 
On Monday, April 16, 2018 at 1:25:29 PM UTC-4, Klaus Kragelund wrote:
On Monday, April 16, 2018 at 2:47:11 PM UTC+2, TTman wrote:
SNIP
So I was thinking about opening up the relay, and mouting it downwards, so i could place a weight on the armature, to measure precisely the force needed to keep the equilibrium state (no movement of the armature), both for the pulled-in case, and also for the released state, so I can calculate the needed holding voltage

(and yes, I have contacted Omron, but they can sofar not present Holding voltage specs)

I could also measure the inductance of the coil, in both pulled-in state and the released state, which also should give me the different in current to obtain the same magnetic field (magnetic path in pulled-in state is shorter)

Anyone got ideas?

Cheers

Klaus

Drive it with a variable voltage PSU ???? Start with 9V to operate, then
reduce the voltage until the relay drops out... then add some margin % ?
Seems simple to me.

I know how to do that, but I need the robustness margin for vibration etc to be valid

Cheers

Klaus
Click to expand...

I like the idea of hanging it upsides down. I have no idea how to
guesstimate the vibration? Say 10g.? (98 m/s^2)
So hang a weight that is 10x the armature weight?

George H.
 
On Monday, 16 April 2018 18:25:29 UTC+1, Klaus Kragelund wrote:
On Monday, April 16, 2018 at 2:47:11 PM UTC+2, TTman wrote:

SNIP
So I was thinking about opening up the relay, and mouting it downwards, so i could place a weight on the armature, to measure precisely the force needed to keep the equilibrium state (no movement of the armature), both for the pulled-in case, and also for the released state, so I can calculate the needed holding voltage

(and yes, I have contacted Omron, but they can sofar not present Holding voltage specs)

I could also measure the inductance of the coil, in both pulled-in state and the released state, which also should give me the different in current to obtain the same magnetic field (magnetic path in pulled-in state is shorter)

Anyone got ideas?

Cheers

Klaus

Drive it with a variable voltage PSU ???? Start with 9V to operate, then
reduce the voltage until the relay drops out... then add some margin % ?
Seems simple to me.

I know how to do that, but I need the robustness margin for vibration etc to be valid

Cheers

Klaus
Click to expand...

the only way to ensure it's valid is test it, using frequency swept vibration. Reducing coil power is nice but it does erode that margin.


NT
 
On 08-Nov-17 8:45 AM, Don Kuenz wrote:
Rheilly Phoull <froggins@iinet.net.au> wrote:
On 8/11/2017 2:16 AM, Don Kuenz wrote:

The DC voltage on many (all?) ham radio power supplies tops out at
about 14VDC. So what do you do when you find the perfect relay, but it
only comes in the 24VDC or 28VDC pull-in flavor?
"Using Direct-Current Relays at Lower Coil Voltages" (KE0FF), in
the current issue of _QEX_, talks about how to use a boost capacitor to
kick start a relay using a voltage lower than the pull-in voltage, Vpi.
The circuit exploits the difference between Vpi and the typically much
smaller holding voltage, Vh. KE0FF's _QEX_ article builds on "How to
Operate 24V relays on 12V" (KO4BB) [1].
The operation of KO4BB's circuit (shown at the link) seems simple
enough. Be that as it may, allow me to "walk through" it for the sake of
thoroughness. Any constructive criticism or elaboration on your part is
encouraged.
Next to the coil is a snubber diode. When the switch is open, the
transistor's shut off and both relay poles are at a Vdd - 0.6V = V1
potential. The capacitor also charges to a V1 potential when the switch
is open.
When the switch is closed the transistor turns on and grounds the
lower pole of the coil. The top diode turns off while the bottom diode
free-wheels the cap and the top pole of the coil up to Vdd + V1. At this
point a Vdd + V1 potential is impressed against the relay's coil, which
causes the relay to close.
The whole trick is to keep enough potential impressed against the
coil long enough for Vh to come into play. At that point, as long as
Vdd is greater than Vh the relay will stay closed. The cap must be sized
to accommodate the timing constant from the coil's internal resistance.

Note.

1. http://www.ko4bb.com/ham_radio/Projects/24V_Relays/

Might be better to use a switch symbol rather than the push button to
avoid confusion.

Yes, a switch works better. The circuit shown in the schematic's
more conceptual than practical. A push button's used to it simple for
the sake of discussion.
The _QEX_ article uses a DPDT switch to embellish the concept. It
then replaces the conceptual switch with MOSFETs in a practical circuit,
which offers digital control.
My mind got so preoccupied with the walk-through that it forgot to
ask about the picture of Tek scope that appears near the bottom of the
link. Does anyone recognize the model of the Tek scope from the picture
of its display?

Thank you,

--
Don Kuenz, KB7RPU
Click to expand...

Tek TDS 210 or 220.
 
I don't want to start a flame-war with everyone on this thread, but circuits like the one described are exactly why I am proud to say I never wanted to get my Amateur Radio license!

It's not the worst hack I've seen (that honor might go to two back-to-back Motorola Mitrek mobiles to make a "repeater"?), but it's in the running.

Disclaimer: I'm presently hyper-sensitive to crappy shortcut circuits.
Co-worker. Don't ask. :)
 
mpm <mpmillard@aol.com> wrote:
I don't want to start a flame-war with everyone on this thread, but circuits
like the one described are exactly why I am proud to say I never wanted to
get my Amateur Radio license!

It's not the worst hack I've seen (that honor might go to two back-to-back
Motorola Mitrek mobiles to make a "repeater"?), but it's in the running.

Disclaimer: I'm presently hyper-sensitive to crappy shortcut circuits.
Co-worker. Don't ask. :)
Click to expand...

Ham radio power supplies typically output ~13VDC. Many coax (microwave)
relays operate only at a higher voltages. That's why this circuit comes
in handy for ham radio operators.
It sounds like your work might suck a little. Maybe you ought to
lighten up, get your ham license, and enjoy the on-the-air party.

Thank you,

--
Don Kuenz, KB7RPU
 
Perry <Perry@null.com> wrote:
On 08-Nov-17 8:45 AM, Don Kuenz wrote:
Rheilly Phoull <froggins@iinet.net.au> wrote:
On 8/11/2017 2:16 AM, Don Kuenz wrote:

The DC voltage on many (all?) ham radio power supplies tops out at
about 14VDC. So what do you do when you find the perfect relay, but it
only comes in the 24VDC or 28VDC pull-in flavor?
"Using Direct-Current Relays at Lower Coil Voltages" (KE0FF), in
the current issue of _QEX_, talks about how to use a boost capacitor to
kick start a relay using a voltage lower than the pull-in voltage, Vpi.
The circuit exploits the difference between Vpi and the typically much
smaller holding voltage, Vh. KE0FF's _QEX_ article builds on "How to
Operate 24V relays on 12V" (KO4BB) [1].
The operation of KO4BB's circuit (shown at the link) seems simple
enough. Be that as it may, allow me to "walk through" it for the sake of
thoroughness. Any constructive criticism or elaboration on your part is
encouraged.
Next to the coil is a snubber diode. When the switch is open, the
transistor's shut off and both relay poles are at a Vdd - 0.6V = V1
potential. The capacitor also charges to a V1 potential when the switch
is open.
When the switch is closed the transistor turns on and grounds the
lower pole of the coil. The top diode turns off while the bottom diode
free-wheels the cap and the top pole of the coil up to Vdd + V1. At this
point a Vdd + V1 potential is impressed against the relay's coil, which
causes the relay to close.
The whole trick is to keep enough potential impressed against the
coil long enough for Vh to come into play. At that point, as long as
Vdd is greater than Vh the relay will stay closed. The cap must be sized
to accommodate the timing constant from the coil's internal resistance.

Note.

1. http://www.ko4bb.com/ham_radio/Projects/24V_Relays/

Might be better to use a switch symbol rather than the push button to
avoid confusion.

Yes, a switch works better. The circuit shown in the schematic's
more conceptual than practical. A push button's used to it simple for
the sake of discussion.
The _QEX_ article uses a DPDT switch to embellish the concept. It
then replaces the conceptual switch with MOSFETs in a practical circuit,
which offers digital control.
My mind got so preoccupied with the walk-through that it forgot to
ask about the picture of Tek scope that appears near the bottom of the
link. Does anyone recognize the model of the Tek scope from the picture
of its display?


Tek TDS 210 or 220.
Click to expand...

------------------------------------------------------------------------
Surplus microwave relays are relatively widely available on eBay and
other surplus stores but they usually have a 24 or 28V coil.

Most of the smaller ones I have (non-latching, SMA connectors) have a
200 ohm coil, and they turn on around 14-16V and turn off around 7-9V,
which makes them unuseable directly from a 12V battery.

If your transverter uses a MA/COM brick or other similar oscillator, you
already need a 21V nominal source, which can be used to drive the
relay(s). However, if you do not already need a higher voltage, it is
unnecessary to build a voltage converter just for the relays, since it
is much simpler to use the circuit below.
------------------------------------------------------------------------

Thank you,

--
Don Kuenz, KB7RPU
 
Perry <Perry@null.com> wrote:
On 08-Nov-17 8:45 AM, Don Kuenz wrote:
Rheilly Phoull <froggins@iinet.net.au> wrote:
On 8/11/2017 2:16 AM, Don Kuenz wrote:

The DC voltage on many (all?) ham radio power supplies tops out at
about 14VDC. So what do you do when you find the perfect relay, but it
only comes in the 24VDC or 28VDC pull-in flavor?
"Using Direct-Current Relays at Lower Coil Voltages" (KE0FF), in
the current issue of _QEX_, talks about how to use a boost capacitor to
kick start a relay using a voltage lower than the pull-in voltage, Vpi.
The circuit exploits the difference between Vpi and the typically much
smaller holding voltage, Vh. KE0FF's _QEX_ article builds on "How to
Operate 24V relays on 12V" (KO4BB) [1].
The operation of KO4BB's circuit (shown at the link) seems simple
enough. Be that as it may, allow me to "walk through" it for the sake of
thoroughness. Any constructive criticism or elaboration on your part is
encouraged.
Next to the coil is a snubber diode. When the switch is open, the
transistor's shut off and both relay poles are at a Vdd - 0.6V = V1
potential. The capacitor also charges to a V1 potential when the switch
is open.
When the switch is closed the transistor turns on and grounds the
lower pole of the coil. The top diode turns off while the bottom diode
free-wheels the cap and the top pole of the coil up to Vdd + V1. At this
point a Vdd + V1 potential is impressed against the relay's coil, which
causes the relay to close.
The whole trick is to keep enough potential impressed against the
coil long enough for Vh to come into play. At that point, as long as
Vdd is greater than Vh the relay will stay closed. The cap must be sized
to accommodate the timing constant from the coil's internal resistance.

Note.

1. http://www.ko4bb.com/ham_radio/Projects/24V_Relays/

Might be better to use a switch symbol rather than the push button to
avoid confusion.

Yes, a switch works better. The circuit shown in the schematic's
more conceptual than practical. A push button's used to it simple for
the sake of discussion.
The _QEX_ article uses a DPDT switch to embellish the concept. It
then replaces the conceptual switch with MOSFETs in a practical circuit,
which offers digital control.
My mind got so preoccupied with the walk-through that it forgot to
ask about the picture of Tek scope that appears near the bottom of the
link. Does anyone recognize the model of the Tek scope from the picture
of its display?


Tek TDS 210 or 220.
Click to expand...

You're a good man. Here's the designer's rational for this circuit (from
the link):

------------------------------------------------------------------------
Surplus microwave relays are relatively widely available on eBay and
other surplus stores but they usually have a 24 or 28V coil.

Most of the smaller ones I have (non-latching, SMA connectors) have a
200 ohm coil, and they turn on around 14-16V and turn off around 7-9V,
which makes them unuseable directly from a 12V battery.

If your transverter uses a MA/COM brick or other similar oscillator, you
already need a 21V nominal source, which can be used to drive the
relay(s). However, if you do not already need a higher voltage, it is
unnecessary to build a voltage converter just for the relays, since it
is much simpler to use the circuit below.
------------------------------------------------------------------------

Thank you,

--
Don Kuenz, KB7RPU
 
On 2018-04-16, Klaus Kragelund <klauskvik@hotmail.com> wrote:
I have a relay that has a specified must operate voltage of 9V (12V relay, so 85% of nominal)

The holding voltage is lower than the must operate, since the must operate is for pulling in the armature. When the armature is pulled in, the magnetic path is lower, and thus needs less current to have the same force on the armature to withstand vibration etc

I do not have a holding spec, but I need it and would like to deduce it from the must operate voltage

So I was thinking about opening up the relay, and mouting it downwards, so i could place a weight on the armature, to measure precisely the force needed to keep the equilibrium state (no movement of the armature), both for the pulled-in case, and also for the released state, so I can calculate the needed holding voltage

(and yes, I have contacted Omron, but they can sofar not present Holding voltage specs)

I could also measure the inductance of the coil, in both pulled-in state and the released state, which also should give me the different in current to obtain the same magnetic field (magnetic path in pulled-in state is shorter)
Click to expand...

Operate voltage is usually 75% of rated, hold voltage usually 25% both
are affected by vibration, gee forces (orientation, acceleration), vibration, aging etc.

> Anyone got ideas?

To measure just hook it up to a variable supply turn the voltage up
and down and shake it etc.
Perhaps connect a lamp to the relay contacts so you can see the state.
Some relays have a half-on state where both contacts are open.


Once you get below its operating voltage the relay
will switch in response to external mechanical impulses.
(Tap on the bottom/back and it turns off, tap pn the front/top and it turns on.
etc...)

if it must be reliable stick to "must operate", or arrange a feedback
loop in-case it drops out...

--
ŘŞ
 
On 2018-04-16, George Herold <gherold@teachspin.com> wrote:
On Monday, April 16, 2018 at 1:25:29 PM UTC-4, Klaus Kragelund wrote:
On Monday, April 16, 2018 at 2:47:11 PM UTC+2, TTman wrote:
SNIP
So I was thinking about opening up the relay, and mouting it downwards, so i could place a weight on the armature, to measure precisely the force needed to keep the equilibrium state (no movement of the armature), both for the pulled-in case, and also for the released state, so I can calculate the needed holding voltage

(and yes, I have contacted Omron, but they can sofar not present Holding voltage specs)

I could also measure the inductance of the coil, in both pulled-in state and the released state, which also should give me the different in current to obtain the same magnetic field (magnetic path in pulled-in state is shorter)

Anyone got ideas?

Cheers

Klaus

Drive it with a variable voltage PSU ???? Start with 9V to operate, then
reduce the voltage until the relay drops out... then add some margin % ?
Seems simple to me.

I know how to do that, but I need the robustness margin for vibration etc to be valid

Cheers

Klaus

I like the idea of hanging it upsides down. I have no idea how to
guesstimate the vibration? Say 10g.? (98 m/s^2)
So hang a weight that is 10x the armature weight?
Click to expand...

Drop it from some height? 10g is like one inch onto a wooden desktop
(guesstimate).

--
ŘŞ
 
tabbypurr@gmail.com writes:

On Monday, 16 April 2018 18:25:29 UTC+1, Klaus Kragelund wrote:
On Monday, April 16, 2018 at 2:47:11 PM UTC+2, TTman wrote:

SNIP
So I was thinking about opening up the relay, and mouting it
downwards, so i could place a weight on the armature, to measure
precisely the force needed to keep the equilibrium state (no
movement of the armature), both for the pulled-in case, and also
for the released state, so I can calculate the needed holding
voltage

(and yes, I have contacted Omron, but they can sofar not present Holding voltage specs)

I could also measure the inductance of the coil, in both
pulled-in state and the released state, which also should give
me the different in current to obtain the same magnetic field
(magnetic path in pulled-in state is shorter)

Anyone got ideas?

Cheers

Klaus

Drive it with a variable voltage PSU ???? Start with 9V to operate, then
reduce the voltage until the relay drops out... then add some margin % ?
Seems simple to me.

I know how to do that, but I need the robustness margin for vibration etc to be valid

Cheers

Klaus

the only way to ensure it's valid is test it, using frequency swept vibration. Reducing coil power is nice but it does erode that margin.
Click to expand...

Even then I think there is still the possibility of variations in the
springs (when new and also perhaps aging). The manufacturers must also
have to allow for this in the spec. So maybe determine what the pull-in
margin actually is and then use the same margin for the hold?

Seems like some other workaround would be more practical here.

There are latched relays, maybe one of those would be better for the
application?


--

John Devereux
 
Jasen Betts <jasen@xnet.co.nz> wrote in news:pb449b$qr8$4@gonzo.alcatraz:

Drop it from some height? 10g is like one inch onto a wooden desktop
(guesstimate).
Click to expand...

That is just stupid. Any hard surface yields an abrupt signature with a
hign, fast slew rate toward infinite Gs. Theoretically.

Pool balls are solid objects, right?

Sorry, but a one inch drop does not yield a 10G shock into an object.

If you want to look at vibe prcedures AND specs, look at hard drive
manufacturers.

They take over 40Gs when not under power.

They tell you exactly how they get their figures.
 
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