Re: IBM 4331 Mainframe 3 phase converter

[Paul Koning via cctalk]

> On May 4, 2017, at 11:54 AM, Jon Elson via cctalk  
> wrote:
> 
> ...  But, you DO need a true sine wave source, and VFDs do not produce sine 
> waves, they put out 400 V PWM waveforms that look fine to a motor, but not 
> good at all to electronic loads.

I wonder how true that is.  Consider that (for machines of this era) power 
supplies are probably transformer input, to a rectifier and then a filter.  The 
transformer would smooth out the VFD output pulses, and whatever is left would 
definitely be removed by the output filter.  The only question I can see is 
whether the rectifier diodes have enough reverse voltage margin to deal with 
whatever peaks pass through the transformer.  (The transformer itself certainly 
will, given normal insulation design/test practice for power transformers.)

If the power supply is a swiching regulator, the details are slightly different 
but the overall picture is similar.  Then you begin with a rectifier, which 
would have to be able to deal with the input spikes, followed by some amount of 
filtering.  Once past that I don't see any further issues.

An electronic circuit that looks at the incoming AC waveform directly would 
certainly have issues with a VFD, but I can't think of too many examples of 
that.  A KW-11/L is one exception that comes to mind... :-)

paul

Re: IBM 4331 Mainframe 3 phase converter

[Guy Sotomayor Jr via cctalk]

> On May 4, 2017, at 8:59 AM, Jon Elson  wrote:
> 
> On 05/04/2017 10:36 AM, Guy Sotomayor Jr via cctalk wrote:
>>> 
>> OK, that’s not helping.  Here’s what I have (from IBM site planning docs 
>> GC22-7064-10 and GC22-7069-2):
>> 3340-A2 DASD: 2.2 kVA 3-phase
>> 3340-B2 DASD: 1.7 kVA 3-phase (powered from 3340-A2)
>> 3803 Tape Control unit: 1.8 kVA 3-phase
>> 3420 Tape drive: 2.9 kVA 3-phase (powered from 3803) (x2)
>> 2821 control unit: 1.4 kVA 3-phase
>> 1403N1 Printer: 1.5 kVA 3-phase (powered from 2821)
>> 2540 card reader/punch: 1.2 kVA 3-phase (powered from 2821)
>> 
>> So I have 3 potential power feeds:
>> DASD: 3.9 kVA
>> Tape: 10.5 kVA
>> I/O: 4.1 kVA
>> 
>> For a total of 18.5 kVA
>> 
>> So the several $1000 question is how do the kVA’s map into 208v 3-phase amps?
> 18.5 KVA /208 = 88.94
> 88.94 / 1.732 = 51 A
> 
> Since this is given as KVA, it should include the power factor.
>>   Depending upon how that works out I need to figure out if 2/3 converters 
>> make sense or just one big one.
>> 
>> My simple minded conversion is to take the 18.5kVA, multiply by 1000 and 
>> divide by 208.  That gives me just shy of 90A.  Do I then divide by 3 to get 
>> A/phase?  If so, then it’s 30A per phase which seems reasonable.  But I 
>> don’t know if that’s the correct formulation.
> It isn't.  See above.  A lot of this is circulating current, so the real 
> power draw from the mains will be less.  Still, most likely over 10 
> real-power KW from your 240 V single-phase mains.

Thanks.

So if I want to run it off of one converter, that needs to be able to supply 
51A.  If I split it, then I would end up with:
Tape: 30A
DASD: 11A
I/O: 12A

So at this point it comes down to cost.  If I can find one that can supply 60A 
that’s reasonable that would work.  Otherwise I’d likely get either 2 30A 
converters or 1 30A and 2 15A (if they come in those sizes).  ;-)  I’ll just 
have to figure out what makes the most sense cost wise.

Thanks.

TTFN - Guy

Re: IBM 4331 Mainframe 3 phase converter

[Paul Koning via cctalk]

kVA is simply kilovolts times amps.  It is roughly a synonym for kW, except 
that it probably ignores the phase angle.  So for resistive loads, kVA == kW 
but for inductive or capacitive loads, kVA would be larger.

1 hp == 746 W.  But when people talk about phase converter hp limits, they are 
looking not just at the steady state load but also at the startup peak current, 
which is a fairly substantial multiple of the steady state load.

For your application, you probably have some motor loads and possibly some 
others (power supplies).  If they are mostly motor loads, use the steady state 
kVA spec and convert that back to hp by dividing by 0.746.  Alternatively, if 
the converter has a rated steady state load, match that against the steady 
state power spec for the machine.  The peak current handling of the converter 
will take care of either motor startup peaks, or power supply inrush current.

paul

> On May 4, 2017, at 10:36 AM, Guy Sotomayor Jr via cctalk 
>  wrote:
> 
> Does anyone know how to convert KVa to 208v 3-phase currents and/or HP?  
> IBM’s docs all specify power in KVa and most of the 3 phase converters (other 
> than what Bob posted) seem to specify HP.  If I’m going to spend serious coin 
> on a phase converter (I think I found it online for ~$3k…ouch!), I want to 
> make sure it’s sized properly.
> 
> Thanks.
> 
> TTFN - Guy

Re: IBM 4331 Mainframe 3 phase converter

[Jon Elson via cctalk]

On 05/04/2017 10:36 AM, Guy Sotomayor Jr via cctalk wrote:

On May 4, 2017, at 8:04 AM, jim stephens via cctalk  
wrote:



On 5/4/2017 7:36 AM, Guy Sotomayor Jr via cctalk wrote:

Does anyone know how to convert KVa to 208v 3-phase currents and/or HP?  IBM’s 
docs all specify power in KVa and most of the 3 phase converters (other than 
what Bob posted) seem to specify HP.  If I’m going to spend serious coin on a 
phase converter (I think I found it online for ~$3k…ouch!), I want to make sure 
it’s sized properly.

Thanks.

TTFN - Guy

You will also need to get the motor start information, or you will vaporize a 
phase converter.

Another possible approach that a friend is taking is to take three single phase 
identical UPS system and synch the phases of the three converter output 
circuits to proper three phase.

He's made up one from three junk APC units I've got.  I can forward info if you 
would like on this approach from him.  One thing that helps is he snagged and 
maintained the drawings of all of the APC and other output circuits over the 
years and has good info on how to pull this off.

The quadrature power will be something to deal with on your three phase loads, 
but you may be able to run quite a bit of single phase hardware directly off of 
the mains.


OK, that’s not helping.  Here’s what I have (from IBM site planning docs 
GC22-7064-10 and GC22-7069-2):
3340-A2 DASD: 2.2 kVA 3-phase
3340-B2 DASD: 1.7 kVA 3-phase (powered from 3340-A2)
3803 Tape Control unit: 1.8 kVA 3-phase
3420 Tape drive: 2.9 kVA 3-phase (powered from 3803) (x2)
2821 control unit: 1.4 kVA 3-phase
1403N1 Printer: 1.5 kVA 3-phase (powered from 2821)
2540 card reader/punch: 1.2 kVA 3-phase (powered from 2821)

So I have 3 potential power feeds:
DASD: 3.9 kVA
Tape: 10.5 kVA
I/O: 4.1 kVA

For a total of 18.5 kVA

So the several $1000 question is how do the kVA’s map into 208v 3-phase amps?

18.5 KVA /208 = 88.94
88.94 / 1.732 = 51 A

Since this is given as KVA, it should include the power factor.

   Depending upon how that works out I need to figure out if 2/3 converters 
make sense or just one big one.

My simple minded conversion is to take the 18.5kVA, multiply by 1000 and divide 
by 208.  That gives me just shy of 90A.  Do I then divide by 3 to get A/phase?  
If so, then it’s 30A per phase which seems reasonable.  But I don’t know if 
that’s the correct formulation.
It isn't.  See above.  A lot of this is circulating current, 
so the real power draw from the mains will be less.  Still, 
most likely over 10 real-power KW from your 240 V 
single-phase mains.


Jon

Jon

Re: IBM 4331 Mainframe 3 phase converter

[Jon Elson via cctalk]

On 05/04/2017 09:36 AM, Guy Sotomayor Jr via cctalk wrote:

Does anyone know how to convert KVa to 208v 3-phase currents and/or HP?  IBM’s 
docs all specify power in KVa and most of the 3 phase converters (other than 
what Bob posted) seem to specify HP.  If I’m going to spend serious coin on a 
phase converter (I think I found it online for ~$3k…ouch!), I want to make sure 
it’s sized properly.


Line current times voltage give you KVA per line.  Then, 
multiply by 1.732 to get total KVA.  KW / .7457 give HP, not 
counting losses or power factor.  You don't actually need a 
3-phase source, you only need to generate one new phase
(although if the 4331, etc. want 208, you probably don't 
want to feed it 240 V).  But, you DO need a true sine wave 
source, and VFDs do not produce sine waves, they put out 400 
V PWM waveforms that look fine to a motor, but not good at 
all to electronic loads.


It is possible that a hefty used VFD with an appropriate 
filter would turn it into a nice sine wave at lower cost.  
For multiple KVA loads, that might be a more economical way 
to go, if you don't mind creating such a filter.  (Probably 
be good to put a transformer between the VFD/filter and the 
computers, so the line could be balanced around neutral, too.)


Jon

Re: IBM 4331 Mainframe 3 phase converter

[Guy Sotomayor Jr via cctalk]

> On May 4, 2017, at 8:04 AM, jim stephens via cctalk  
> wrote:
> 
> 
> 
> On 5/4/2017 7:36 AM, Guy Sotomayor Jr via cctalk wrote:
>> Does anyone know how to convert KVa to 208v 3-phase currents and/or HP?  
>> IBM’s docs all specify power in KVa and most of the 3 phase converters 
>> (other than what Bob posted) seem to specify HP.  If I’m going to spend 
>> serious coin on a phase converter (I think I found it online for 
>> ~$3k…ouch!), I want to make sure it’s sized properly.
>> 
>> Thanks.
>> 
>> TTFN - Guy
> You will also need to get the motor start information, or you will vaporize a 
> phase converter.
> 
> Another possible approach that a friend is taking is to take three single 
> phase identical UPS system and synch the phases of the three converter output 
> circuits to proper three phase.
> 
> He's made up one from three junk APC units I've got.  I can forward info if 
> you would like on this approach from him.  One thing that helps is he snagged 
> and maintained the drawings of all of the APC and other output circuits over 
> the years and has good info on how to pull this off.
> 
> The quadrature power will be something to deal with on your three phase 
> loads, but you may be able to run quite a bit of single phase hardware 
> directly off of the mains.
> 

OK, that’s not helping.  Here’s what I have (from IBM site planning docs 
GC22-7064-10 and GC22-7069-2):
3340-A2 DASD: 2.2 kVA 3-phase
3340-B2 DASD: 1.7 kVA 3-phase (powered from 3340-A2)
3803 Tape Control unit: 1.8 kVA 3-phase
3420 Tape drive: 2.9 kVA 3-phase (powered from 3803) (x2)
2821 control unit: 1.4 kVA 3-phase
1403N1 Printer: 1.5 kVA 3-phase (powered from 2821)
2540 card reader/punch: 1.2 kVA 3-phase (powered from 2821)

So I have 3 potential power feeds:
DASD: 3.9 kVA
Tape: 10.5 kVA
I/O: 4.1 kVA

For a total of 18.5 kVA

So the several $1000 question is how do the kVA’s map into 208v 3-phase amps?  
Depending upon how that works out I need to figure out if 2/3 converters make 
sense or just one big one.

My simple minded conversion is to take the 18.5kVA, multiply by 1000 and divide 
by 208.  That gives me just shy of 90A.  Do I then divide by 3 to get A/phase?  
If so, then it’s 30A per phase which seems reasonable.  But I don’t know if 
that’s the correct formulation.

TTFN - Guy

Re: IBM 4331 Mainframe 3 phase converter

[jim stephens via cctalk]

On 5/4/2017 7:36 AM, Guy Sotomayor Jr via cctalk wrote:

Does anyone know how to convert KVa to 208v 3-phase currents and/or HP?  IBM’s 
docs all specify power in KVa and most of the 3 phase converters (other than 
what Bob posted) seem to specify HP.  If I’m going to spend serious coin on a 
phase converter (I think I found it online for ~$3k…ouch!), I want to make sure 
it’s sized properly.

Thanks.

TTFN - Guy
You will also need to get the motor start information, or you will 
vaporize a phase converter.


Another possible approach that a friend is taking is to take three 
single phase identical UPS system and synch the phases of the three 
converter output circuits to proper three phase.


He's made up one from three junk APC units I've got.  I can forward info 
if you would like on this approach from him.  One thing that helps is he 
snagged and maintained the drawings of all of the APC and other output 
circuits over the years and has good info on how to pull this off.


The quadrature power will be something to deal with on your three phase 
loads, but you may be able to run quite a bit of single phase hardware 
directly off of the mains.


thanks
Jim

Re: IBM 4331 Mainframe 3 phase converter

[Guy Sotomayor Jr via cctalk]

Does anyone know how to convert KVa to 208v 3-phase currents and/or HP?  IBM’s 
docs all specify power in KVa and most of the 3 phase converters (other than 
what Bob posted) seem to specify HP.  If I’m going to spend serious coin on a 
phase converter (I think I found it online for ~$3k…ouch!), I want to make sure 
it’s sized properly.

Thanks.

TTFN - Guy

> On May 3, 2017, at 11:26 PM, Curious Marc via cctalk <cctalk@classiccmp.org> 
> wrote:
> 
> Bob,
> 
> Thanks, that looks just about perfect. Solid state, true sinusoid 3 phase, 
> 30A continuous but can do 140A for 4 seconds - seems made to power a big 
> bunch of vacuum column tapes.
> 
> Marc
> 
> 
> 
> From: cctalk <cctalk-boun...@classiccmp.org> on behalf of 
> "cctalk@classiccmp.org" <cctalk@classiccmp.org>
> Reply-To: Bob Rosenbloom <boba...@sbcglobal.net>, "cctalk@classiccmp.org" 
> <cctalk@classiccmp.org>
> Date: Wednesday, May 3, 2017 at 10:04 PM
> To: "cctalk@classiccmp.org" <cctalk@classiccmp.org>
> Subject: Re: IBM 4331 Mainframe 3 phase converter
> 
> 
> 
> I use a solid state one, an older version of this:
> 
> http://www.phasetechnologies.com/downloads/products/phase-perfect/pt330specs.pdf
> 
> 
> 
> Bought on ebay quite a few years ago.
> 
> 
> 
> I also have a small Phoenix rotary phase converter, also from ebay. This 
> 
> one seems to have unbalanced outputs.
> 
> I believe it is for motor loads only.
> 
> 
> 
> Bob
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 

Re: IBM 4331 Mainframe 3 phase converter

[Curious Marc via cctalk]

Bob,

Thanks, that looks just about perfect. Solid state, true sinusoid 3 phase, 30A 
continuous but can do 140A for 4 seconds - seems made to power a big bunch of 
vacuum column tapes.

Marc

 

From: cctalk <cctalk-boun...@classiccmp.org> on behalf of 
"cctalk@classiccmp.org" <cctalk@classiccmp.org>
Reply-To: Bob Rosenbloom <boba...@sbcglobal.net>, "cctalk@classiccmp.org" 
<cctalk@classiccmp.org>
Date: Wednesday, May 3, 2017 at 10:04 PM
To: "cctalk@classiccmp.org" <cctalk@classiccmp.org>
Subject: Re: IBM 4331 Mainframe 3 phase converter

 

I use a solid state one, an older version of this:

http://www.phasetechnologies.com/downloads/products/phase-perfect/pt330specs.pdf

 

Bought on ebay quite a few years ago.

 

I also have a small Phoenix rotary phase converter, also from ebay. This 

one seems to have unbalanced outputs.

I believe it is for motor loads only.

 

Bob

 

 

 

 

 

Re: IBM 4331 Mainframe 3 phase converter

[Bob Rosenbloom via cctalk]

I use a solid state one, an older version of this:
http://www.phasetechnologies.com/downloads/products/phase-perfect/pt330specs.pdf

Bought on ebay quite a few years ago.

I also have a small Phoenix rotary phase converter, also from ebay. This 
one seems to have unbalanced outputs.

I believe it is for motor loads only.

Bob



On 5/3/2017 1:23 PM, Curious Marc via cctalk wrote:

Let me know what you come up with for the 3 phase converter solution. I have 
the exact same problem right now to provide power for my 3 3420 tapes and the 
3803 controller. Also have 220V 50A single phase coming in the shop (er, 
garage), courtesy of the EV charger.
Marc

On Apr 30, 2017, at 9:38 PM, Guy Sotomayor Jr via cctalk 
 wrote:

Just to let folks know that I finally moved the IBM 4331 Mainframe this past 
weekend
from where it was currently stored to my shop.  Pictures are here:
https://www.flickr.com/gp/150223282@N04/NrX91K 


As can be seen in the pictures, it filled a 26’ box truck that I had rented for 
this purpose.
Right now I just have it placed somewhat in my shop.  Some early tasks will be:
   * I have to verify that I have everything.  Even if I missed some items, 
they won’t be
 scrapped.  I just need to go over what is currently in my shop and verify 
that I didn’t
 leave anything behind.  I’m mostly worried about cables at this point.
  * I have to figure out some way to produce enough “clean” 3-phase power to 
run the
peripherals (the CPU is 220v single phase) as I only have 220v single phase 
coming
into my shop.

Starting to power it up will probably be a while yet.  ;-)

TTFN - Guy





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