25 Jul
2018
25 Jul
'18
6:50 a.m.
Why don't you simply power it through an inverter that will output 60 Hz, eventually
even "down to" 120 V , true sine wave, of course ??? They are not that expensive
by now.
And be carefull : motor designed for 60 Hz, running "under" 50 Hz, OR THE
OPPOSITE, I do not recall !!!, display a significant reduced life time.
I have to check which is which, but I know this is a question of saturated magnetic field.
Better check first.
25 Jul
25 Jul
6:54 a.m.
On Jul 25, 2018, at 9:50 AM, GerardCJAT via cctech
<cctech at classiccmp.org> wrote:
Why don't you simply power it through an inverter that will output 60 Hz, eventually
even "down to" 120 V , true sine wave, of course ??? They are not that expensive
by now.
I wouldn't worry about "true sine wave". That seems more of a marketing
thing anyway, and motors don't care. Just feed them with a variable frequency motor
drive and all should be well.
And be carefull : motor designed for 60 Hz, running
"under" 50 Hz, OR THE OPPOSITE, I do not recall !!!, display a significant
reduced life time.
I have to check which is which, but I know this is a question of saturated magnetic
field. Better check first.
That doesn't sound right. If you run the frequency up high enough you might get into
problems with magnetic materials not designed for it. And much lower probably gives you
reduced torque. But 50 vs. 60 Hz is a trivial difference for a motor, I can't see any
reasons for that to cause trouble. I routinely run my lathe at half frequency if not
less, and it doesn't complain.
paul
9:48 a.m.
On Wed, Jul 25, 2018 at 7:54 AM, Paul Koning via cctalk <
cctalk at classiccmp.org> wrote:
I'm not sure about motors, but 60 Hz power transformers can't handle as
high a maximum power (or current) when used for 50 Hz. The maximum power
has to be derated. Some transformers are specified/sold with a single power
specification for both 50 and 60 Hz use, which just means that the vendor
has built the necessary derating into even the 60 Hz specification.
Some products were built using different transformers for 50 vs 60 Hz
models, and the 60 Hz models uses a transformer inadequate for 50 Hz
operation.
On Jul 25,
2018, at 9:50 AM, GerardCJAT via cctech <
cctech at classiccmp.org> wrote:
Why don't you simply power it through an inverter that will output 60
Hz,
eventually even "down to" 120 V , true sine wave, of course ??? They
are not that expensive by now.
I wouldn't worry about "true sine wave". That seems more of a marketing
thing anyway, and motors don't care. Just feed them with a variable
frequency motor drive and all should be well.
And be carefull : motor designed for 60 Hz,
running "under" 50 Hz, OR
THE OPPOSITE, I do not recall !!!, display a
significant reduced life time.
I have to check which is which, but I know this
is a question of
saturated magnetic field. Better check first.
That doesn't sound right. If you run the frequency up high enough you
might get into problems with magnetic materials not designed for it. And
much lower probably gives you reduced torque. But 50 vs. 60 Hz is a
trivial difference for a motor, I can't see any reasons for that to cause
trouble. I routinely run my lathe at half frequency if not less, and it
doesn't complain.
11:06 a.m.
Eric Smith via cctalk wrote:
On Wed, Jul 25, 2018 at 7:54 AM, Paul Koning via
cctalk <
cctalk at classiccmp.org> wrote:
I'm not sure about motors, but 60 Hz power transformers can't handle as
high a maximum power (or current) when used for 50 Hz. The maximum power
has to be derated. Some transformers are specified/sold with a single power
specification for both 50 and 60 Hz use, which just means that the vendor
has built the necessary derating into even the 60 Hz specification.
Some products were built using different transformers for 50 vs 60 Hz
models, and the 60 Hz models uses a transformer inadequate for 50 Hz
operation.
It has to do with the physics of flux linkages and saturation. Under
sinusoidal operation, voltage is proportional to the product of maximum
flux and frequency.? If you fix the voltage, in order to operate at 5/6
of the nominal frequency you need a flux that is? 6/5 the nominal one.?
This might not seem like much more flux, but due to the nonlinear
magnetization characteristics,? the required magnetization current will
not be 6/5 times the nominal current, but it could in fact be three
times higher or even more, and highly distorted.
Under-frequency and over-voltage can kill power transformers easily.
A transformer designed to operate at 50 Hz will therefore have much more
iron mass in its core, power and voltage being equal.? That's why in
airplanes power is distributed at 400Hz; the transformers will be much
lighter.
carlos.
On Jul
25, 2018, at 9:50 AM, GerardCJAT via cctech <
cctech at classiccmp.org>
wrote:
Why don't you simply power it through an
inverter that will output 60
Hz, eventually even "down to" 120 V , true
sine wave, of course ??? They
are not that expensive by now.
I wouldn't worry about "true sine wave". That seems more of a marketing
thing anyway, and motors don't care. Just feed them with a variable
frequency motor drive and all should be well.
And be carefull : motor designed for 60 Hz,
running "under" 50 Hz, OR
THE OPPOSITE, I do not recall !!!, display a
significant reduced life time.
I have to check which is which, but I know this
is a question of
saturated magnetic field. Better check first.
That doesn't sound right. If you run the frequency up high enough you
might get into problems with magnetic materials not designed for it. And
much lower probably gives you reduced torque. But 50 vs. 60 Hz is a
trivial difference for a motor, I can't see any reasons for that to cause
trouble. I routinely run my lathe at half frequency if not less, and it
doesn't complain.
26 Jul
26 Jul
5:26 a.m.
Omg finally I know why airplanes use 400Hz, thank you! Honestly that's been
on my mind for years.
=]
On Wed, Jul 25, 2018 at 2:06 PM Carlos E Murillo-Sanchez via cctalk <
cctalk at classiccmp.org> wrote:
Eric Smith via cctalk wrote:
power
--
Anders Nelson
+1 (517) 775-6129
www.erogear.com
On Wed, Jul 25, 2018 at 7:54 AM, Paul Koning via
cctalk <
cctalk at classiccmp.org> wrote:
>> On Jul 25, 2018, at 9:50 AM, GerardCJAT via cctech <
> cctech at classiccmp.org> wrote:
>> Why don't you simply power it through an inverter that will output 60
> Hz, eventually even "down to" 120 V , true sine wave, of course ??? They
> are not that expensive by now.
>
> I wouldn't worry about "true sine wave". That seems more of a
marketing
> thing anyway, and motors don't care. Just feed them with a variable
> frequency motor drive and all should be well.
>
>> And be carefull : motor designed for 60 Hz, running "under" 50 Hz, OR
> THE OPPOSITE, I do not recall !!!, display a significant reduced life
time.
>> I have to check which is which, but I
know this is a question of
> saturated magnetic field. Better check first.
>
> That doesn't sound right. If you run the frequency up high enough you
> might get into problems with magnetic materials not designed for it.
And
> much lower probably gives you reduced torque.
But 50 vs. 60 Hz is a
> trivial difference for a motor, I can't see any reasons for that to
cause
trouble.
I routinely run my lathe at half frequency if not less, and it
doesn't complain.
I'm not sure about motors, but 60 Hz power transformers can't handle as
high a maximum power (or current) when used for 50 Hz. The maximum power
has to be derated. Some transformers are specified/sold with a single specification for both 50 and 60 Hz use, which
just means that the vendor
has built the necessary derating into even the 60 Hz specification.
Some products were built using different transformers for 50 vs 60 Hz
models, and the 60 Hz models uses a transformer inadequate for 50 Hz
operation.
It has to do with the physics of flux linkages and saturation. Under
sinusoidal operation, voltage is proportional to the product of maximum
flux and frequency. If you fix the voltage, in order to operate at 5/6
of the nominal frequency you need a flux that is 6/5 the nominal one.
This might not seem like much more flux, but due to the nonlinear
magnetization characteristics, the required magnetization current will
not be 6/5 times the nominal current, but it could in fact be three
times higher or even more, and highly distorted.
Under-frequency and over-voltage can kill power transformers easily.
A transformer designed to operate at 50 Hz will therefore have much more
iron mass in its core, power and voltage being equal. That's why in
airplanes power is distributed at 400Hz; the transformers will be much
lighter.
carlos.
-- 
6:55 a.m.
That is not the whole story of 400Hz. The other part of that story is that now, all of the
downstream equipment that uses the 400 Hz can have much simpler AC to DC power supplies in
them. At 400 Hz it is much easier to regulate and filter out ripple. So instead of every
piece of equipment each having lots of large capacitors, now they only need small
capacitors. Space is at a premium as well as weight on a plane.
________________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Anders Nelson via
cctalk <cctalk at classiccmp.org>
Sent: Thursday, July 26, 2018 8:26 AM
To: Carlos E Murillo-Sanchez; General Discussion: On-Topic and Off-Topic Posts;
carlos_murillo at ieee.org
Subject: Re: RK05 spindle pulleys - trade 50Hz vs 60Hz?
Omg finally I know why airplanes use 400Hz, thank you! Honestly that's been
on my mind for years.
=]
On Wed, Jul 25, 2018 at 2:06 PM Carlos E Murillo-Sanchez via cctalk <
cctalk at classiccmp.org> wrote:
Eric Smith via cctalk wrote:
power
--
Anders Nelson
+1 (517) 775-6129
www.erogear.com
On Wed, Jul 25, 2018 at 7:54 AM, Paul Koning via
cctalk <
cctalk at classiccmp.org> wrote:
>> On Jul 25, 2018, at 9:50 AM, GerardCJAT via cctech <
> cctech at classiccmp.org> wrote:
>> Why don't you simply power it through an inverter that will output 60
> Hz, eventually even "down to" 120 V , true sine wave, of course ??? They
> are not that expensive by now.
>
> I wouldn't worry about "true sine wave". That seems more of a
marketing
> thing anyway, and motors don't care. Just feed them with a variable
> frequency motor drive and all should be well.
>
>> And be carefull : motor designed for 60 Hz, running "under" 50 Hz, OR
> THE OPPOSITE, I do not recall !!!, display a significant reduced life
time.
>> I have to check which is which, but I
know this is a question of
> saturated magnetic field. Better check first.
>
> That doesn't sound right. If you run the frequency up high enough you
> might get into problems with magnetic materials not designed for it.
And
> much lower probably gives you reduced torque.
But 50 vs. 60 Hz is a
> trivial difference for a motor, I can't see any reasons for that to
cause
trouble.
I routinely run my lathe at half frequency if not less, and it
doesn't complain.
I'm not sure about motors, but 60 Hz power transformers can't handle as
high a maximum power (or current) when used for 50 Hz. The maximum power
has to be derated. Some transformers are specified/sold with a single specification for both 50 and 60 Hz use, which
just means that the vendor
has built the necessary derating into even the 60 Hz specification.
Some products were built using different transformers for 50 vs 60 Hz
models, and the 60 Hz models uses a transformer inadequate for 50 Hz
operation.
It has to do with the physics of flux linkages and saturation. Under
sinusoidal operation, voltage is proportional to the product of maximum
flux and frequency. If you fix the voltage, in order to operate at 5/6
of the nominal frequency you need a flux that is 6/5 the nominal one.
This might not seem like much more flux, but due to the nonlinear
magnetization characteristics, the required magnetization current will
not be 6/5 times the nominal current, but it could in fact be three
times higher or even more, and highly distorted.
Under-frequency and over-voltage can kill power transformers easily.
A transformer designed to operate at 50 Hz will therefore have much more
iron mass in its core, power and voltage being equal. That's why in
airplanes power is distributed at 400Hz; the transformers will be much
lighter.
carlos.
--
7:49 a.m.
On Jul 26, 2018, at 9:55 AM, W2HX via cctalk
<cctalk at classiccmp.org> wrote:
That is not the whole story of 400Hz. The other part of that story is that now, all of
the downstream equipment that uses the 400 Hz can have much simpler AC to DC power
supplies in them. At 400 Hz it is much easier to regulate and filter out ripple. So
instead of every piece of equipment each having lots of large capacitors, now they only
need small capacitors. Space is at a premium as well as weight on a plane.
This even applies to some terrestrial equipment. CDC used 400 Hz 3-phase power for the
6000 series mainframes. 3-phase power cuts the ripple by a large fraction and raises the
ripple frequency 3x; 400 Hz instead of 60 or 50 raises the ripple frequency further by
that ratio. So high power supplies get much smaller, both in the transformers and in the
filter capacitors.
The 400 Hz came from motor-generators. Those also clean up the power a lot, because any
spikes or brief dips are absorbed by the mechanical intertia and don't appear on the
output.
paul
7:54 a.m.
To get that power, did they have to use a rotary convertor from 60Hz
3-phase to get 400Hz?
https://en.wikipedia.org/wiki/Rotary_converter
=]
--
Anders Nelson
+1 (517) 775-6129
www.erogear.com
On Thu, Jul 26, 2018 at 10:49 AM Paul Koning via cctalk <
cctalk at classiccmp.org> wrote:
On Jul 26, 2018, at 9:55 AM, W2HX via cctalk
<cctalk at classiccmp.org>
wrote:
That is not the whole story of 400Hz. The other part of that story is
that now,
all of the downstream equipment that uses the 400 Hz can have
much simpler AC to DC power supplies in them. At 400 Hz it is much easier
to regulate and filter out ripple. So instead of every piece of equipment
each having lots of large capacitors, now they only need small capacitors.
Space is at a premium as well as weight on a plane.
This even applies to some terrestrial equipment. CDC used 400 Hz 3-phase
power for the 6000 series mainframes. 3-phase power cuts the ripple by a
large fraction and raises the ripple frequency 3x; 400 Hz instead of 60 or
50 raises the ripple frequency further by that ratio. So high power
supplies get much smaller, both in the transformers and in the filter
capacitors.
The 400 Hz came from motor-generators. Those also clean up the power a
lot, because any spikes or brief dips are absorbed by the mechanical
intertia and don't appear on the output.
paul
8:14 a.m.
On 07/26/2018 07:54 AM, Anders Nelson via cctalk wrote:
To get that power, did they have to use a rotary
convertor from 60Hz
3-phase to get 400Hz?
https://en.wikipedia.org/wiki/Rotary_converter
As Paul mentioned, less a "rotary converter" than a AC motor-AC
generator hookup. One advantage is that the rotational inertia in such
a setup does have the ability to smooth over small power disruptions.
Such MG setups were very common in industry before modern
semiconductors. When I had a summer job showing movies at a drive-in
theater (a long time ago), the supply for the carbon-arc lamps was a
40hp motor powered by 3-phase 60Hz, driving a DC generator. In WWII
radio equipment, MGs in a unitzed form called "dynamotors" were used to
supply the high-voltage anode voltage for the tubes. Electroplating
shops similarly used large DC generator setups to supply plating current.
3 phase full-wave rectified AC has approximately 87% DC content at 6x
the supply frequency. So for 400Hz, the ripple is only 13 percent at
2400 Hz before filtering.
--Chuck
8:22 a.m.
Best mailing list ever. Thanks for the detail!
=]
--
Anders Nelson
+1 (517) 775-6129
www.erogear.com
On Thu, Jul 26, 2018 at 11:14 AM Chuck Guzis via cctalk <
cctalk at classiccmp.org> wrote:
On 07/26/2018 07:54 AM, Anders Nelson via cctalk
wrote:
To get that power, did they have to use a rotary
convertor from 60Hz
3-phase to get 400Hz?
https://en.wikipedia.org/wiki/Rotary_converter
As Paul mentioned, less a "rotary converter" than a AC motor-AC
generator hookup. One advantage is that the rotational inertia in such
a setup does have the ability to smooth over small power disruptions.
Such MG setups were very common in industry before modern
semiconductors. When I had a summer job showing movies at a drive-in
theater (a long time ago), the supply for the carbon-arc lamps was a
40hp motor powered by 3-phase 60Hz, driving a DC generator. In WWII
radio equipment, MGs in a unitzed form called "dynamotors" were used to
supply the high-voltage anode voltage for the tubes. Electroplating
shops similarly used large DC generator setups to supply plating current.
3 phase full-wave rectified AC has approximately 87% DC content at 6x
the supply frequency. So for 400Hz, the ripple is only 13 percent at
2400 Hz before filtering.
--Chuck
8:26 a.m.
On Thu, Jul 26, 2018 at 4:14 PM, Chuck Guzis via cctalk
<cctalk at classiccmp.org> wrote:
Such MG setups were very common in industry before
modern
semiconductors. When I had a summer job showing movies at a drive-in
theater (a long time ago), the supply for the carbon-arc lamps was a
40hp motor powered by 3-phase 60Hz, driving a DC generator. In WWII
radio equipment, MGs in a unitzed form called "dynamotors" were used to
supply the high-voltage anode voltage for the tubes. Electroplating
shops similarly used large DC generator setups to supply plating current.
I believe if you want to be pedantic that a motor-generator set is a motor
(with an armature/rotor and a field/stator) mechanically coupled to a
generator (with its own armature/rotor and field/stator) whereas a
dynamotor has a common field/stator (and possibly both armature
windings have to be wound on the same core).
-tony
9:05 a.m.
On 07/26/2018 10:26 AM, Tony Duell via cctalk wrote:
On Thu, Jul 26, 2018 at 4:14 PM, Chuck Guzis via
cctalk
<cctalk at classiccmp.org> wrote:
Yes, a dynamotor has ONE armature with a commutator on each
end. There is one set of field poles for the whole unit,
too. The low-voltage input and high-voltage output windings
are laid in the same slots in the armature.
Jon
Such MG setups were very common in industry
before modern
semiconductors. When I had a summer job showing movies at a drive-in
theater (a long time ago), the supply for the carbon-arc lamps was a
40hp motor powered by 3-phase 60Hz, driving a DC generator. In WWII
radio equipment, MGs in a unitzed form called "dynamotors" were used to
supply the high-voltage anode voltage for the tubes. Electroplating
shops similarly used large DC generator setups to supply plating current.
I
believe if you want to be pedantic that a motor-generator set is a motor
(with an armature/rotor and a field/stator) mechanically coupled to a
generator (with its own armature/rotor and field/stator) whereas a
dynamotor has a common field/stator (and possibly both armature
windings have to be wound on the same core).
9:17 a.m.
On Jul 26, 2018, at 11:26 AM, Tony Duell via cctalk
<cctalk at classiccmp.org> wrote:
On Thu, Jul 26, 2018 at 4:14 PM, Chuck Guzis via cctalk
<cctalk at classiccmp.org> wrote:
Yes, so Wikipedia is wrong to describe a dynamotor as a motor-generator and show it in the
m-g article rather than the rotary transformer article.
I remember the dynamotors shown in that photo, my father had that exact unit and several
other "Command Set" radios. The dynamotors clearly had a single armature, with
input brushes at one side and output brushes at the other.
paul
Such MG setups were very common in industry
before modern
semiconductors. When I had a summer job showing movies at a drive-in
theater (a long time ago), the supply for the carbon-arc lamps was a
40hp motor powered by 3-phase 60Hz, driving a DC generator. In WWII
radio equipment, MGs in a unitzed form called "dynamotors" were used to
supply the high-voltage anode voltage for the tubes. Electroplating
shops similarly used large DC generator setups to supply plating current.
I believe if you want to be pedantic that a motor-generator set is a motor
(with an armature/rotor and a field/stator) mechanically coupled to a
generator (with its own armature/rotor and field/stator) whereas a
dynamotor has a common field/stator (and possibly both armature
windings have to be wound on the same core).
9:28 a.m.
New subject: 400Hz supplies; was: RK05 spindle pulleys - trade 50Hz vs 60Hz?
On 07/26/2018 08:26 AM, Tony Duell wrote:
I believe if you want to be pedantic that a
motor-generator set is a motor
(with an armature/rotor and a field/stator) mechanically coupled to a
generator (with its own armature/rotor and field/stator) whereas a
dynamotor has a common field/stator (and possibly both armature
windings have to be wound on the same core).
Hence my term "unitized", which I thought to give the basic idea without
going into excessive detail on an obsolete device.
In connection with similar low-power high-voltage supplies, I could also
have mentioned vibrator-transformer supplies, run from DC battery, used
very often in lower-power tube gear, such as auto radios and even photo
strobe flash.
The high-voltage DC was obtained from the transformer secondary by
either a traditional tube (very often cold cathode gas) rectifier, later
solid-state (selenium or silicon) or an additional set of contacts on
the vibrator itself. Notorious for kicking up all sorts of RF noise.
But this is way off-topic.
--Chuck
9:35 a.m.
New subject: 400Hz supplies; was: RK05 spindle pulleys - trade 50Hz vs 60Hz?
On Thu, Jul 26, 2018 at 5:28 PM, Chuck Guzis via cctalk
<cctalk at classiccmp.org> wrote:
On 07/26/2018 08:26 AM, Tony Duell wrote:
This is classiccmp. We 'do' obsolete devices here :-)
I believe if you want to be pedantic that a
motor-generator set is a motor
(with an armature/rotor and a field/stator) mechanically coupled to a
generator (with its own armature/rotor and field/stator) whereas a
dynamotor has a common field/stator (and possibly both armature
windings have to be wound on the same core).
Hence my term "unitized", which I thought to give the basic idea without
going into excessive detail on an obsolete device.
In connection with similar low-power high-voltage supplies, I could also
have mentioned vibrator-transformer supplies, run from DC battery, used
very often in lower-power tube gear, such as auto radios and even photo
strobe flash.
Indeed. I've never seen a photoflash using such a supply, but I have read
about them. One day I'll add one to my collection.
They were commonly used in car radios over here too.
The high-voltage DC was obtained from the transformer secondary by
either a traditional tube (very often cold cathode gas) rectifier, later
0Z4 IiIRC wa a common rectifier valve.
solid-state (selenium or silicon) or an additional set
of contacts on
the vibrator itself. Notorious for kicking up all sorts of RF noise.
The latter was known as a 'synchronous vibrator' (at least over here)
as the 2 sets of contacts were synchronised to (a) apply a pulse to one
end of the primary winding and (b) select the appropriate end of
the secondary which will have an high voltage pulse of the correct
polarity.
A mad friend of mine commented that a google search for a spare
part for his car radio directed him to an awful lot of 'adult' sites...
-tony
10:34 a.m.
New subject: 400Hz supplies; was: RK05 spindle pulleys - trade 50Hz vs 60Hz?
On 07/26/2018 09:35 AM, Tony Duell wrote:
On Thu, Jul 26, 2018 at 5:28 PM, Chuck Guzis via
cctalk
Indeed. I've never seen a photoflash using such a
supply, but I have read
about them. One day I'll add one to my collection.
I recall fooling with a 60s era Dormeyer model. Not only did it use a
vibrator supply, but also a rechargeable stainless-steel enclosed
battery. A very compact unit in comparison to those units using the
510V primary battery. Either was vastly more compact than the Graflex
stroboflash-2x225V batteries in a very heavy supply.
--Chuck
11:13 a.m.
New subject: 400Hz supplies; was: RK05 spindle pulleys - trade 50Hz vs 60Hz?
Chuck...? ? ?horrible? flashback of? using this? strobe? unit in my? younger? days as a
photographer.? Still? was nicer than a? pocket? full of? flashbulbs? being? set off in a?
suit? pocket? from? carpet static? ?electricity...
We? actually? still have? of of these units in the? photographic? collection...
?
?
Ed#? ?www.smecc.org?
?
In a message dated 7/26/2018 10:34:57 AM US Mountain Standard Time, cctalk at
classiccmp.org writes:
?
Either was vastly more compact than the Graflex
stroboflash-2x225V batteries in a very heavy supply.
--Chuck
11:51 a.m.
New subject: 400Hz supplies; was: RK05 spindle pulleys - trade 50Hz vs 60Hz?
smecc has? stashed a? huge? mother gen? set? ? 115? 60cy? in? 115 400 cy? out.
was used to? run? ? rca avq? 10? raradr.... we? have.... but? could? run many? ?many
things... it is? huge,,, these things exist out there? if? you need one,....
?
Ed#? www.smecc.org?
In a message dated 7/26/2018 9:36:04 AM US Mountain Standard Time, cctalk at
classiccmp.org writes:
?
On Thu, Jul 26, 2018 at 5:28 PM, Chuck Guzis via cctalk
<cctalk at classiccmp.org> wrote:
On 07/26/2018 08:26 AM, Tony Duell wrote:
This is classiccmp. We 'do' obsolete devices here :-)
I believe if you want to be pedantic that a
motor-generator set is a motor
(with an armature/rotor and a field/stator) mechanically coupled to a
generator (with its own armature/rotor and field/stator) whereas a
dynamotor has a common field/stator (and possibly both armature
windings have to be wound on the same core).
Hence my term "unitized", which I thought to give the basic idea without
going into excessive detail on an obsolete device.
In connection with similar low-power high-voltage supplies, I could also
have mentioned vibrator-transformer supplies, run from DC battery, used
very often in lower-power tube gear, such as auto radios and even photo
strobe flash.
Indeed. I've never seen a photoflash using such a supply, but I have read
about them. One day I'll add one to my collection.
They were commonly used in car radios over here too.
The high-voltage DC was obtained from the transformer secondary by
either a traditional tube (very often cold cathode gas) rectifier, later
0Z4 IiIRC wa a common rectifier valve.
solid-state (selenium or silicon) or an additional set
of contacts on
the vibrator itself. Notorious for kicking up all sorts of RF noise.
The latter was known as a 'synchronous vibrator' (at least over here)
as the 2 sets of contacts were synchronised to (a) apply a pulse to one
end of the primary winding and (b) select the appropriate end of
the secondary which will have an high voltage pulse of the correct
polarity.
A mad friend of mine commented that a google search for a spare
part for his car radio directed him to an awful lot of 'adult' sites...
-tony
12:15 p.m.
New subject: 400Hz supplies; was: RK05 spindle pulleys - trade 50Hz vs 60Hz?
On 07/26/2018 11:51 AM, Ed Sharpe wrote:
smecc has stashed a huge mother gen set 115 60cy in 115
400 cy out. was used to run rca avq 10 raradr.... we have....
but could run many many things... it is huge,,, these things
exist out there if you need one,...
400Hz power was also used in aviation gear. I remember having a stock
of small surplus 400Hz transformers salvaged from various bits of
equipment purchased on Chicago's "Surplus Row".
Transformers are much smaller than their 50/60 Hz cousins.
On the other hand, when I worked in a steel mill, much of the power
distribution was 25Hz. Transformers were much larger. At some point,
one of the mills converted their lighting from incandescent to
mercury-vapor running from that 25Hz supply. I'm surprised that nobody
experienced seizures from the flicker.
--Chuck
23 Aug
23 Aug
2:02 a.m.
New subject: 400Hz supplies; was: RK05 spindle pulleys - trade 50Hz vs 60Hz?
tor 2018-07-26 klockan 12:15 -0700 skrev Chuck Guzis via cctalk:
On 07/26/2018 11:51 AM, Ed Sharpe wrote:
The electric arc furnace works much better at 25 Hz.
The hydro power station in Trollh?ttan was first built as a 25 Hz
because :
desiredness of electric power for the metallurgical industry in
Trollh?tan.
Trouble: the other intended customer Gothenburg city wanted 50 Hz.
The last 25 Hz generator in Trollh?ttan was taken off the electric grid
in 1959.
smecc has stashed a huge mother gen set 115 60cy in 115
400 cy out. was used to run rca avq 10 raradr....
we have....
but could run many many things... it is huge,,, these things
exist out there if you need one,...
400Hz power was also used in aviation gear. I remember having a
stock
of small surplus 400Hz transformers salvaged from various bits of
equipment purchased on Chicago's "Surplus Row".
Transformers are much smaller than their 50/60 Hz cousins.
On the other hand, when I worked in a steel mill, much of the power
distribution was 25Hz. Transformers were much larger. At some
point,
one of the mills converted their lighting from incandescent to
mercury-vapor running from that 25Hz supply. I'm surprised that
nobody
experienced seizures from the flicker.
26 Jul
26 Jul
9:02 a.m.
On 07/26/2018 09:54 AM, Anders Nelson via cctalk wrote:
To get that power, did they have to use a rotary
convertor from 60Hz
3-phase to get 400Hz?
IBM mainframes in the late 1950's early 1960's (707x and
709x series) used motor generators to generate 400 Hz
3-phase power, which was distributed to all the major
components.
For the 360, they came up with a solid state version, it ran
the CPU, memory and such on 2500 Hz single-phase power,
using a "converter-inverter". It rectified and filtered the
3-phase 50- or 60-Hz input to DC, and then used ultra-fast
SCRs to invert it. But, the energy stored in the filter
caps in that was way smaller than the rotational energy in a
motor generator set. So, the 360 was susceptible to power
glitches and dips. For the 370, they went back to a
motor-generator set actually INSIDE the CPU cabinet to
produce 415 Hz 3-phase power. Larger systems often had a
UPS with electronic inverters in them.
Jon
9:15 a.m.
On Jul 26, 2018, at 10:54 AM, Anders Nelson
<anders.k.nelson at gmail.com> wrote:
To get that power, did they have to use a rotary convertor from 60Hz 3-phase to get
400Hz?
https://en.wikipedia.org/wiki/Rotary_converter
No, a motor-generator: https://en.wikipedia.org/wiki/Motor?generator. Same purpose, but
constructed as a motor attached to a generator, rather than the two merged into a single
armature.
http://www.bitsavers.org/pdf/cdc/cyber/cyber_70/fieldEngr/60142400B_6000_Se…
shows the ones CDC used, starting on page 27.
paul
25 Jul
25 Jul
11:17 a.m.
On Wed, Jul 25, 2018 at 5:48 PM, Eric Smith via cctalk
<cctalk at classiccmp.org> wrote:
I'm not sure about motors, but 60 Hz power
transformers can't handle as
high a maximum power (or current) when used for 50 Hz. The maximum power
has to be derated. Some transformers are specified/sold with a single power
specification for both 50 and 60 Hz use, which just means that the vendor
has built the necessary derating into even the 60 Hz specification.
Some products were built using different transformers for 50 vs 60 Hz
models, and the 60 Hz models uses a transformer inadequate for 50 Hz
operation.
This may well be true (I think it is), but the original question was about a
particular device, the DEC RK05 disk drive. According to the maintenance
manual (on bitsavers), the coversion between 50Hz and 60Hz involves changing
the motor pulley. No comment about replacing the motor, the start capacitor,
or anything else.
Does anyone have an RK05 IPB (Illustrated Parts Breakdown) manual? It would
be interesting to see if there are different part numbers for the motor (start
capacitor, blower...) for 50Hz and 60Hz versions.
Going back to a much earlier comment, I think this pulley is something that
would be a lot easier to turn (on a lathe) rather than 3D print.
-tony
11:27 a.m.
On Jul 25, 2018, at 11:17 AM, Tony Duell via cctalk
<cctalk at classiccmp.org> wrote:
On Wed, Jul 25, 2018 at 5:48 PM, Eric Smith via cctalk
<cctalk at classiccmp.org> wrote:
A while ago (can?t recall how many years), I acquired a number of 50Hz RK05?s.
Since I live in a 60Hz country, getting the drives to work simply involved changing
the pulley from the 50Hz version to the 60Hz version and changing the voltage
jumpers (the drives have worked fine after that change). I believe that the switch
over is documented somewhere?but it?s been *way* too long since I did it.
As far as I recall, the pulleys have the frequency stamped on them.
For the OP who started this thread. Yes, I still have the 50Hz pulleys *somewhere*
but at this point they're not easy to find as they are packed in a tote in the
basement
of my shop (which is packed floor to ceiling with boxes and totes?there isn?t even
an isle to walk around in?just a small area that you can almost turn around in).
TTFN - Guy
I'm not sure about motors, but 60 Hz power
transformers can't handle as
high a maximum power (or current) when used for 50 Hz. The maximum power
has to be derated. Some transformers are specified/sold with a single power
specification for both 50 and 60 Hz use, which just means that the vendor
has built the necessary derating into even the 60 Hz specification.
Some products were built using different transformers for 50 vs 60 Hz
models, and the 60 Hz models uses a transformer inadequate for 50 Hz
operation.
This may well be true (I think it is), but the original question was about a
particular device, the DEC RK05 disk drive. According to the maintenance
manual (on bitsavers), the coversion between 50Hz and 60Hz involves changing
the motor pulley. No comment about replacing the motor, the start capacitor,
or anything else.
Does anyone have an RK05 IPB (Illustrated Parts Breakdown) manual? It would
be interesting to see if there are different part numbers for the motor (start
capacitor, blower...) for 50Hz and 60Hz versions.
Going back to a much earlier comment, I think this pulley is something that
would be a lot easier to turn (on a lathe) rather than 3D print.
12:45 p.m.
On Wed, Jul 25, 2018 at 12:17 PM, Tony Duell <ard.p850ug1 at gmail.com> wrote:
On Wed, Jul 25, 2018 at 5:48 PM, Eric Smith via
cctalk
Right. I was just responding to a later, general comment about motors.
There are, however, DEC products other than the RK05 which had different
transformers for 50 Hz and 60 Hz. For example, the H771 power supply used
in the RX01 and RX02. There were three H771 models, The H771A for 90-132
VAC 60 Hz, The H771C for 90-132 VAC 50 Hz, and the H771D for 180-264 VAC 50
Hz. The H771A uses a transformer rated for 60 Hz. The H771C and H771D both
use the same 50 Hz rated transformer, with different wiring. The H771C and
H771D also require one of two different wiring harnesses to cover the
entire mains voltage range, e.g., 90-120 VAC vs 100-132 VAC for the H771C,
or twice those voltages for the H771D.
Some products were built using different
transformers for 50 vs 60 Hz
models, and the 60 Hz models uses a transformer inadequate for 50 Hz
operation.
This may well be true (I think it is), but the original question was about
a
particular device, the DEC RK05 disk drive. According to the maintenance
manual (on bitsavers), the coversion between 50Hz and 60Hz involves
changing
the motor pulley. No comment about replacing the motor, the start
capacitor,
or anything else.
8:32 p.m.
There are, however, DEC products other than the RK05
which had different
transformers for 50 Hz and 60 Hz. For example, the H771 power supply used
in the RX01 and RX02. There were three H771 models, The H771A for 90-132
VAC 60 Hz, The H771C for 90-132 VAC 50 Hz, and the H771D for 180-264 VAC 50
Hz. The H771A uses a transformer rated for 60 Hz. The H771C and H771D both
use the same 50 Hz rated transformer, with different wiring. The H771C and
H771D also require one of two different wiring harnesses to cover the
entire mains voltage range, e.g., 90-120 VAC vs 100-132 VAC for the H771C,
or twice those voltages for the H771D.
IIRC that's a ferroresonant transformer (with a capacitor to resonate one of the
windings to a harmonic of the power line frequency), so it's not
surprising it has
to be changed for 50Hz or 60Hz input.
-tony
9:21 p.m.
I can't find my IPB, but the maintenance manual shows there were both 50
and 60 hz versions made.
I think I've shipped them overseas, but never modified them. I did ship a
lot of RX02 drives overseas, and to properly convert them the pulleys,
belts, and wiring harness had to be swapped. We were always on the lookout
for parts. I still have a few different wiring harnesses around here
somewhere.
BA11-K conversions were also common. I still have interesting stories and
parts about them.
What gets me with the RK05 is how you can swap pulleys without swapping
belts. A few products had pulleys with two grooves, one for 50, the other
for 60. But you still needed a different belt.
Paul
On Wed, Jul 25, 2018 at 10:32 PM, Tony Duell via cctalk <
cctalk at classiccmp.org> wrote:
There are,
however, DEC products other than the RK05 which had different
transformers for 50 Hz and 60 Hz. For example, the H771 power supply used
in the RX01 and RX02. There were three H771 models, The H771A for 90-132
VAC 60 Hz, The H771C for 90-132 VAC 50 Hz, and the H771D for 180-264 VAC
50
Hz. The H771A uses a transformer rated for 60 Hz.
The H771C and H771D
both
use the same 50 Hz rated transformer, with
different wiring. The H771C
and
H771D also require one of two different wiring
harnesses to cover the
entire mains voltage range, e.g., 90-120 VAC vs 100-132 VAC for the
H771C,
or twice those voltages for the H771D.
IIRC that's a ferroresonant transformer (with a capacitor to resonate one
of the
windings to a harmonic of the power line frequency), so it's not
surprising it has
to be changed for 50Hz or 60Hz input.
-tony
26 Jul
26 Jul
12:19 a.m.
2018-07-26 6:21 GMT+02:00 Paul Anderson via cctalk <cctalk at classiccmp.org>:
I can't find my IPB, but the maintenance manual
shows there were both 50
and 60 hz versions made.
I think I've shipped them overseas, but never modified them. I did ship a
lot of RX02 drives overseas, and to properly convert them the pulleys,
belts, and wiring harness had to be swapped. We were always on the lookout
for parts. I still have a few different wiring harnesses around here
somewhere.
BA11-K conversions were also common. I still have interesting stories and
parts about them.
What gets me with the RK05 is how you can swap pulleys without swapping
belts. A few products had pulleys with two grooves, one for 50, the other
for 60. But you still needed a different belt.
You need to move the motor to a new position in the RK05. The drive is
already prepared for all this. It is just the pulley, moving the motor and
the 220VAC jumper that is needed.
/Mattis
Paul
On Wed, Jul 25, 2018 at 10:32 PM, Tony Duell via cctalk <
cctalk at classiccmp.org> wrote:
> There are, however, DEC products other than
the RK05 which had
different
> transformers for 50 Hz and 60 Hz. For
example, the H771 power supply
used
> in the RX01 and RX02. There were three H771
models, The H771A for
90-132
> VAC 60 Hz, The H771C for 90-132 VAC 50 Hz,
and the H771D for 180-264
VAC
50
Hz. The H771A uses a transformer rated for 60 Hz.
The H771C and H771D
both
use the same 50 Hz rated transformer, with
different wiring. The H771C
and
H771D also require one of two different wiring
harnesses to cover the
entire mains voltage range, e.g., 90-120 VAC vs 100-132 VAC for the
H771C,
or twice those voltages for the H771D.
IIRC that's a ferroresonant transformer (with a capacitor to resonate one
of the
windings to a harmonic of the power line frequency), so it's not
surprising it has
to be changed for 50Hz or 60Hz input.
-tony
28 Jul
28 Jul
6:58 p.m.
On Jul 26, 2018, at 12:19 AM, Mattis Lind via cctalk
<cctalk at classiccmp.org> wrote:
You need to move the motor to a new position in the RK05. The drive is
already prepared for all this. It is just the pulley, moving the motor and
the 220VAC jumper that is needed.
I'm just working on my second RK05 drive now, to see if I can get it going by VCF West
(I'm going to get crazy this year and rent a truck and show the 11/45, so some other
people can enjoy it :-))
In any case, I can confirm that the power supply and transformers are jumper-able for
220VAC, and the motor is on a spring-tensioned swing arm, so it probably accommodates a
different pulley just fine. HOWEVER, I noticed today that my particular motor has an
ominous bright orange sticker on it that explicitly says "60 Hz ONLY". As far
as I know, its an original motor. FWIW!
https://drive.google.com/file/d/1ZpupgCaQ2InqQrv1uruBJPZZGlDUTuwW/view
<https://drive.google.com/file/d/1ZpupgCaQ2InqQrv1uruBJPZZGlDUTuwW/view>
cheers,
--FritzM.
7:02 p.m.
On Jul 26, 2018, at 12:19 AM, Mattis Lind via cctalk
<cctalk at classiccmp.org <mailto:cctalk at classiccmp.org>> wrote:
You need to move the motor to a new position in the RK05. The drive is
already prepared for all this. It is just the pulley, moving the motor and
the 220VAC jumper that is needed.
I'm just working on my second RK05 drive now, to see if I can get it going by VCF West
(I'm going to get crazy this year and rent a truck and show the 11/45, so some other
people can enjoy it :-))
In any case, I can confirm that the power supply and transformers are jumper-able for
220VAC, and the motor is on a spring-tensioned swing arm, so it probably accommodates a
different pulley just fine. HOWEVER, I noticed today that my particular motor has an
ominous bright orange sticker on it that explicitly says "60 Hz ONLY". As far
as I know, its an original motor. FWIW!
https://drive.google.com/file/d/1ZpupgCaQ2InqQrv1uruBJPZZGlDUTuwW/view
<https://drive.google.com/file/d/1ZpupgCaQ2InqQrv1uruBJPZZGlDUTuwW/view>
cheers,
--FritzM.
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