Contactor coil: 50 Hz vs. 60 Hz

[DaveC]

I may be able to obtain a very small 2-pole 240 vac contactor I need rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz? Just noisy?

Please don't ask or suggest other sources. This is a very specific device and
I've not been able to locate other than this.

Thanks,
Dave

 

[Rich Grise]

DaveC wrote:

I may be able to obtain a very small 2-pole 240 vac contactor I need rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz? Just noisy?

Please don't ask or suggest other sources. This is a very specific device
and I've not been able to locate other than this.

Plug one into 60 Hz and find out what happens. It will probably work just

fine. The Mfr only rated it for 50 because they weren't expecting
international sales.

Are you allowed to tell us why it has to be such a narrow menu of choices?

Thanks,
Rich

 

[Andrew Gabriel]

In article <0001HW.CA807E1401D86A41B01029BF@news.eternal-september.org>,
DaveC <invalid@invalid.net> writes:

I may be able to obtain a very small 2-pole 240 vac contactor I need rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz? Just noisy?

Yes, the hold-in force will be proportionally less. If the
coil impedance was due entirely to the inductance, it would
be 50/60ths of the force. However, part of the current limiting
is done by the coil resistance, and that won't change so the
reduction in hold-in force will actually be less than this.

The pull-in force before the magnetic core is closed also
depend on the impedance and resistance, but the impedance
will be lower, and thus the pull-in force will be reduced by
even less.

The pull-in force usually has to overcome a faily weak return
spring. The hold-in force has to overcome a stronger contact
pressure spring. Providing both these conditions are still met,
you should be OK. Ideally, you should check that you have a
reasonable working margin by testing the coil at lower
voltage. If you don't, then the contactor might fail to
close properly on minimum supply conditions which could cause
it to burn out.

I would not expect it to be more noisy if it closes properly.
Noise would be an indication that is isn't closing properly.

Of course, you void all waranties and certifications by
operating it outside of it's specified ratings. The
manufacturers advice should be sought, but unless you are
buying lots of them, they probably won't commit other than
to say it's at your own risk.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

 

[petrus bitbyter]

"DaveC" <invalid@invalid.net> schreef in bericht
news:0001HW.CA807E1401D86A41B01029BF@news.eternal-september.org...

I may be able to obtain a very small 2-pole 240 vac contactor I need rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz? Just noisy?

Please don't ask or suggest other sources. This is a very specific device
and
I've not been able to locate other than this.

Thanks,
Dave

As we have very limited information about this device and its usage, I can
only suggest two possible solutions:
- The easy one: Just try it out.
- Build a piece of electronics that converts your 60Hz to 50Hz.
Dimensions of that electronics depend on the required current.

petrsu bitbyter

 

[Spehro Pefhany]

On Mon, 29 Aug 2011 08:58:55 +0000 (UTC), the renowned
andrew@cucumber.demon.co.uk (Andrew Gabriel) wrote:

In article <0001HW.CA807E1401D86A41B01029BF@news.eternal-september.org>,
DaveC <invalid@invalid.net> writes:
I may be able to obtain a very small 2-pole 240 vac contactor I need rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz? Just noisy?

Yes, the hold-in force will be proportionally less. If the
coil impedance was due entirely to the inductance, it would
be 50/60ths of the force. However, part of the current limiting
is done by the coil resistance, and that won't change so the
reduction in hold-in force will actually be less than this.

The pull-in force before the magnetic core is closed also
depend on the impedance and resistance, but the impedance
will be lower, and thus the pull-in force will be reduced by
even less.

The pull-in force usually has to overcome a faily weak return
spring. The hold-in force has to overcome a stronger contact
pressure spring. Providing both these conditions are still met,
you should be OK. Ideally, you should check that you have a
reasonable working margin by testing the coil at lower
voltage. If you don't, then the contactor might fail to
close properly on minimum supply conditions which could cause
it to burn out.

<snip>

A side effect of reduced holding force can be that it is more
sensitive to opening due to external vibration in the wrong axis (and
especially so when the input voltage is on the low side). That could
cause malfunction of whatever it's connected to and premature failure
of the contactor. This might not be so easy to test without a shaker
table etc., but it should be considered if the operating conditions
involve vibration (including vibration from another nearby contactor).


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[John Fields]

On Sun, 28 Aug 2011 23:21:56 -0700, DaveC <invalid@invalid.net> wrote:

I may be able to obtain a very small 2-pole 240 vac contactor I need rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz? Just noisy?

Please don't ask or suggest other sources. This is a very specific device and
I've not been able to locate other than this.

---
Not knowing the specifics about the coil makes predicting what will
happen at 60Hz difficult.

However, assuming that the inductive reactance and resistance of the
coil will remain constant at 50 and 60Hz means that the impedance of
the coil at 60Hz will be 1.2 times (60Hz/50Hz) what it is at 50Hz.

Consequently, the current in the coil at 60Hz will be about 83% of
what it is at 50Hz.

If that turns out to be a problem, a higher drive voltage could be
used in order to increase the current, namely 1.2 times 240V; 288V.


That could easily be accomplished using a transformer to boost the
240V mains to 288V, like this: (View with a fixed pitch font.)


240AC>-----+--+
| |
oP||S
R||E
I||Co
| |
| +-----> \
| > 288AC TO COIL
240AC>-----+--------> /

The transformer would need a 240V primary, a 48V secondary, and a VA
rating greater than or equal to the contactor coil's rating.

If you go here:

http://www.signaltransformer.com/content/split-bobbin-with-isolation

and select the input as 115/230 and the output as 48, you'll wind up
with 5 transformers rated at from 6 to 400 VA, one of which would
surely work.

Also, many manufacturers make similar transformers, and Digi-Key and
Mouser stock quite a few.


--
JF

 

[NT]

On Aug 29, 7:21 am, DaveC <inva...@invalid.net> wrote:

I may be able to obtain a very small 2-pole 240 vac contactor I need rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz? Just noisy?

Please don't ask or suggest other sources. This is a very specific device and
I've not been able to locate other than this.

Thanks,
Dave

IME relays pull in at in the region of half rated voltage, and dc
ratings are typically about half the voltage of the ac rating, which
gives an idea of how much current is determined by L and how much by
R. Running your relay on 220v 60Hz it will work fine. Contact closing
speed will be slightly slower. Margin will be reduced, but its only
being reduced from enormous to slightly less enormous, so its a non-
issue except in very unusual situations. The vibration tolerance of
the contacts will be little affected in practice; if your environment
is harsh enough to shake the relay contact open, then you've got
bigger worries than contacts crackling.

If instead you meant you would use it on 110v 60Hz, then dont. But you
could use diodes to get a higher dc voltage and use that.


NT

 

[NT]

On Aug 29, 3:03 pm, John Fields <jfie...@austininstruments.com> wrote:

On Sun, 28 Aug 2011 23:21:56 -0700, DaveC <inva...@invalid.net> wrote:
I may be able to obtain a very small 2-pole 240 vac contactor I need rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz? Just noisy?

Please don't ask or suggest other sources. This is a very specific device and
I've not been able to locate other than this.


Not knowing the specifics about the coil makes predicting what will
happen at 60Hz difficult.

However, assuming that the inductive reactance and resistance of the
coil will remain constant at 50 and 60Hz means that the impedance of
the coil at 60Hz will be 1.2 times (60Hz/50Hz) what it is at 50Hz.

no, only the L component of the impedance will be 1.2 times as high.

Consequently, the current in the coil at 60Hz will be about 83% of
what it is at 50Hz.

If that turns out to be a problem, a higher drive voltage could be
used in order to increase the current, namely 1.2 times 240V; 288V.

That could easily be accomplished using a transformer to boost the
240V mains to 288V, like this: (View with a fixed pitch font.)

240AC>-----+--+
           |  |
          oP||S
           R||E
           I||Co  
           |  |
           |  +-----> \
           |           > 288AC TO COIL
240AC>-----+--------> /

The transformer would need a 240V primary, a 48V secondary, and a VA
rating greater than or equal to the contactor coil's rating.

these are the kind of 'solutions' that happen when people dont put the
relevant numbers to things.

 

[John Fields]

On Mon, 29 Aug 2011 07:28:53 -0700 (PDT), NT <meow2222@care2.com>
wrote:

On Aug 29, 3:03 pm, John Fields <jfie...@austininstruments.com> wrote:
On Sun, 28 Aug 2011 23:21:56 -0700, DaveC <inva...@invalid.net> wrote:
I may be able to obtain a very small 2-pole 240 vac contactor I need rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz? Just noisy?

Please don't ask or suggest other sources. This is a very specific device and
I've not been able to locate other than this.


Not knowing the specifics about the coil makes predicting what will
happen at 60Hz difficult.

However, assuming that the inductive reactance and resistance of the
coil will remain constant at 50 and 60Hz means that the impedance of
the coil at 60Hz will be 1.2 times (60Hz/50Hz) what it is at 50Hz.

no, only the L component of the impedance will be 1.2 times as high.

---
Well, that's true, so let's just see how far off I was, by using a
real-world example.

I have an old P&B MR5A here with a 240V 50/60Hz coil.

The coil has a resistance of 4800 ohms, and an open inductance of 14.5
henrys, so it has an impedance of 6616 ohms at 50 Hz, and 7270 ohms at
60 Hz.

7270 - 6616 = 1.1, so my error was 1 part in 11, or a little less than
10%

I can live with that.
---

Consequently, the current in the coil at 60Hz will be about 83% of
what it is at 50Hz.

If that turns out to be a problem, a higher drive voltage could be
used in order to increase the current, namely 1.2 times 240V; 288V.

That could easily be accomplished using a transformer to boost the
240V mains to 288V, like this: (View with a fixed pitch font.)

240AC>-----+--+
           |  |
          oP||S
           R||E
           I||Co  
           |  |
           |  +-----> \
           |           > 288AC TO COIL
240AC>-----+--------> /

The transformer would need a 240V primary, a 48V secondary, and a VA
rating greater than or equal to the contactor coil's rating.

these are the kind of 'solutions' that happen when people dont put the
relevant numbers to things.

---
Well, your tone is certainly insulting, while the solution remains
valid, but since the voltage into the coil will only be 11% low, the
transformer secondary will only have to supply 26V instead of 48.

In reality, 24V will be fine.

--
JF

 

[cbarn24050@aol.com]

On Aug 29, 3:25 pm, NT <meow2...@care2.com> wrote:

On Aug 29, 7:21 am, DaveC <inva...@invalid.net> wrote:

I may be able to obtain a very small 2-pole 240 vac contactor I need rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz? Just noisy?

Please don't ask or suggest other sources. This is a very specific device and
I've not been able to locate other than this.

Thanks,
Dave

IME relays pull in at in the region of half rated voltage, and dc
ratings are typically about half the voltage of the ac rating, which
gives an idea of how much current is determined by L and how much by
R. Running your relay on 220v 60Hz it will work fine. Contact closing
speed will be slightly slower. Margin will be reduced, but its only
being reduced from enormous to slightly less enormous, so its a non-
issue except in very unusual situations. The vibration tolerance of
the contacts will be little affected in practice; if your environment
is harsh enough to shake the relay contact open, then you've got
bigger worries than contacts crackling.

If instead you meant you would use it on 110v 60Hz, then dont. But you
could use diodes to get a higher dc voltage and use that.

NT

Finally someone comes up with the correct answer.

 

[Ian Field]

"NT" <meow2222@care2.com> wrote in message
news:c89fedd0-49ca-49fe-96d2-7d6bb328d22a@n12g2000yqh.googlegroups.com...
On Aug 29, 3:03 pm, John Fields <jfie...@austininstruments.com> wrote:

On Sun, 28 Aug 2011 23:21:56 -0700, DaveC <inva...@invalid.net> wrote:
I may be able to obtain a very small 2-pole 240 vac contactor I need
rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz? Just noisy?

Please don't ask or suggest other sources. This is a very specific device
and
I've not been able to locate other than this.


Not knowing the specifics about the coil makes predicting what will
happen at 60Hz difficult.

However, assuming that the inductive reactance and resistance of the
coil will remain constant at 50 and 60Hz means that the impedance of
the coil at 60Hz will be 1.2 times (60Hz/50Hz) what it is at 50Hz.

no, only the L component of the impedance will be 1.2 times as high.

Consequently, the current in the coil at 60Hz will be about 83% of
what it is at 50Hz.

If that turns out to be a problem, a higher drive voltage could be
used in order to increase the current, namely 1.2 times 240V; 288V.

That could easily be accomplished using a transformer to boost the
240V mains to 288V, like this: (View with a fixed pitch font.)

240AC>-----+--+
| |
oP||S
R||E
I||Co
| |
| +-----> \
| > 288AC TO COIL
240AC>-----+--------> /

The transformer would need a 240V primary, a 48V secondary, and a VA
rating greater than or equal to the contactor coil's rating.

these are the kind of 'solutions' that happen when people dont put the
relevant numbers to things.

-----------------------------------------

I'd have accepted the figures as near enough and the transformer with
stacked 48V secondary (wired as an autotransformer) as a convenient way to
do the job.

Even if the figures aren't correct to the nth decimal place, they're
probably within tolerance.

 

[John G]

cbarn24050@aol.com wrote on 30/08/2011 :

On Aug 29, 3:25 pm, NT <meow2...@care2.com> wrote:
On Aug 29, 7:21 am, DaveC <inva...@invalid.net> wrote:

I may be able to obtain a very small 2-pole 240 vac contactor I need rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz? Just noisy?
Please don't ask or suggest other sources. This is a very specific device
and I've not been able to locate other than this.
Thanks,
Dave

IME relays pull in at in the region of half rated voltage, and dc
ratings are typically about half the voltage of the ac rating, which
gives an idea of how much current is determined by L and how much by
R. Running your relay on 220v 60Hz it will work fine. Contact closing
speed will be slightly slower. Margin will be reduced, but its only
being reduced from enormous to slightly less enormous, so its a non-
issue except in very unusual situations. The vibration tolerance of
the contacts will be little affected in practice; if your environment
is harsh enough to shake the relay contact open, then you've got
bigger worries than contacts crackling.

If instead you meant you would use it on 110v 60Hz, then dont. But you
could use diodes to get a higher dc voltage and use that.

NT

Finally someone comes up with the correct answer.

And actually practical!
Not the wild theoretical solutions that are often way way over the head
of the original inquirer or so impractical as to be useless.

--
John G.

 

[Spehro Pefhany]

On Mon, 29 Aug 2011 07:25:23 -0700 (PDT), the renowned NT
<meow2222@care2.com> wrote:

On Aug 29, 7:21 am, DaveC <inva...@invalid.net> wrote:
I may be able to obtain a very small 2-pole 240 vac contactor I need rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz? Just noisy?

Please don't ask or suggest other sources. This is a very specific device and
I've not been able to locate other than this.

Thanks,
Dave

IME relays pull in at in the region of half rated voltage, and dc
ratings are typically about half the voltage of the ac rating, which
gives an idea of how much current is determined by L and how much by
R. Running your relay on 220v 60Hz it will work fine. Contact closing
speed will be slightly slower. Margin will be reduced, but its only
being reduced from enormous to slightly less enormous, so its a non-
issue except in very unusual situations.

Well, high ambient temperature and low input voltage. May not be that
unusual. I've seen it happen more than once, particularly in
industrial situations where ambient temperatures can be relatively
high.

I even had to wire an autotransformer into a domestic elevator control
panel because the designer ignored the necessity of allowing for
voltage drop when the drive motor started, which caused chattering of
the AC contactor even in a climate-controlled 22°C environment.

The vibration tolerance of
the contacts will be little affected in practice; if your environment
is harsh enough to shake the relay contact open, then you've got
bigger worries than contacts crackling.

Since the OP didn't describe the environment.. it may or may not be.
For aircraft work (yes, some is 60Hz) it would be a really good idea
to check. If it's sitting on a subpanel with the control cabinet
bolted to the floor rather than to an OBI punch press, not a big deal.

If instead you meant you would use it on 110v 60Hz, then dont. But you
could use diodes to get a higher dc voltage and use that.


NT

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[NT]

On Aug 29, 7:03 pm, John Fields <jfie...@austininstruments.com> wrote:

On Mon, 29 Aug 2011 07:28:53 -0700 (PDT), NT <meow2...@care2.com
wrote:



On Aug 29, 3:03 pm, John Fields <jfie...@austininstruments.com> wrote:
On Sun, 28 Aug 2011 23:21:56 -0700, DaveC <inva...@invalid.net> wrote:
I may be able to obtain a very small 2-pole 240 vac contactor I need rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz? Just noisy?

Please don't ask or suggest other sources. This is a very specific device and
I've not been able to locate other than this.

Not knowing the specifics about the coil makes predicting what will
happen at 60Hz difficult.

However, assuming that the inductive reactance and resistance of the
coil will remain constant at 50 and 60Hz means that the impedance of
the coil at 60Hz will be 1.2 times (60Hz/50Hz) what it is at 50Hz.

no, only the L component of the impedance will be 1.2 times as high.

---
Well, that's true, so let's just see how far off I was, by using a
real-world example.

I have an old P&B MR5A here with a 240V 50/60Hz coil.

The coil has a resistance of 4800 ohms, and an open inductance of 14.5
henrys, so it has an impedance of 6616 ohms at 50 Hz, and 7270 ohms at
60 Hz.

7270 - 6616 = 1.1, so my error was 1 part in 11, or a little less than
10%

I can live with that.
---



Consequently, the current in the coil at 60Hz will be about 83% of
what it is at 50Hz.

If that turns out to be a problem, a higher drive voltage could be
used in order to increase the current, namely 1.2 times 240V; 288V.

That could easily be accomplished using a transformer to boost the
240V mains to 288V, like this: (View with a fixed pitch font.)

240AC>-----+--+
           |  |
          oP||S
           R||E
           I||Co  
           |  |
           |  +-----> \
           |           > 288AC TO COIL
240AC>-----+--------> /

The transformer would need a 240V primary, a 48V secondary, and a VA
rating greater than or equal to the contactor coil's rating.

these are the kind of 'solutions' that happen when people dont put the
relevant numbers to things.


Well, your tone is certainly insulting, while the solution remains
valid, but since the voltage into the coil will only be 11% low, the
transformer secondary will only have to supply 26V instead of 48.

In reality, 24V will be fine.

The relay has a voltage margin of around 50%, the mains supply wont
vary more than 10%, so the transformer is of no use.


NT

 

[NT]

On Aug 29, 7:03 pm, John Fields <jfie...@austininstruments.com> wrote:

On Mon, 29 Aug 2011 07:28:53 -0700 (PDT), NT <meow2...@care2.com
wrote:



On Aug 29, 3:03 pm, John Fields <jfie...@austininstruments.com> wrote:
On Sun, 28 Aug 2011 23:21:56 -0700, DaveC <inva...@invalid.net> wrote:
I may be able to obtain a very small 2-pole 240 vac contactor I need rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz? Just noisy?

Please don't ask or suggest other sources. This is a very specific device and
I've not been able to locate other than this.

Not knowing the specifics about the coil makes predicting what will
happen at 60Hz difficult.

However, assuming that the inductive reactance and resistance of the
coil will remain constant at 50 and 60Hz means that the impedance of
the coil at 60Hz will be 1.2 times (60Hz/50Hz) what it is at 50Hz.

no, only the L component of the impedance will be 1.2 times as high.

---
Well, that's true, so let's just see how far off I was, by using a
real-world example.

I have an old P&B MR5A here with a 240V 50/60Hz coil.

The coil has a resistance of 4800 ohms, and an open inductance of 14.5
henrys, so it has an impedance of 6616 ohms at 50 Hz, and 7270 ohms at
60 Hz.

7270 - 6616 = 1.1, so my error was 1 part in 11, or a little less than
10%

I can live with that.
---



Consequently, the current in the coil at 60Hz will be about 83% of
what it is at 50Hz.

If that turns out to be a problem, a higher drive voltage could be
used in order to increase the current, namely 1.2 times 240V; 288V.

That could easily be accomplished using a transformer to boost the
240V mains to 288V, like this: (View with a fixed pitch font.)

240AC>-----+--+
           |  |
          oP||S
           R||E
           I||Co  
           |  |
           |  +-----> \
           |           > 288AC TO COIL
240AC>-----+--------> /

The transformer would need a 240V primary, a 48V secondary, and a VA
rating greater than or equal to the contactor coil's rating.

these are the kind of 'solutions' that happen when people dont put the
relevant numbers to things.


Well, your tone is certainly insulting,

yes, my apologies.


NT

 

[cbarn24050@aol.com]

On Aug 30, 12:44 am, John G <greent...@ozemail.com.au> wrote:

cbarn24...@aol.com wrote on 30/08/2011 :
Finally someone comes up with the correct answer.

And actually practical!
Not the wild theoretical solutions that are often way way over the head
of the original inquirer or so impractical as to be useless.

--
John G.- Hide quoted text -

Oh they don't do practical here! It's rare for them to get it right
either, this thread is no exception. Some of them even advertise their
place of work! I wonder how much business that has cost them.

 

[David Lesher]

DaveC <invalid@invalid.net> writes:

I may be able to obtain a very small 2-pole 240 vac contactor I need rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz? Just noisy?

It will be happy. If it were a 60Hz on 50, it would not be as happy.

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

 

[David Lesher]

John Fields <jfields@austininstruments.com> writes:

I have an old P&B MR5A here with a 240V 50/60Hz coil.

The coil has a resistance of 4800 ohms, and an open inductance of 14.5
henrys, so it has an impedance of 6616 ohms at 50 Hz, and 7270 ohms at
60 Hz.

What's the inductance while closed?
--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

 

[DaveC]

If instead you meant you would use it on 110v 60Hz, then dont. But you
could use diodes to get a higher dc voltage and use that.
NT

No, there are models for both 115 and 230 in both 50 and 60 Hz flavors. Here
in N. America these are difficult to get so I may have to settle for the 50
Hz models, ordered from Europe. Hence my query.

Thanks,
Dave

 

[DaveC]

..

Since the OP didn't describe the environment.. it may or may not be.
For aircraft work (yes, some is 60Hz) it would be a really good idea
to check. If it's sitting on a subpanel with the control cabinet
bolted to the floor rather than to an OBI punch press, not a big deal.
Best regards,
Spehro Pefhany

It's usually in old (60's & 70's) V-belt driven letterpress type printing
presses (think "clamshell" press). No vibration at the controls.

Thanks,
Dave