50Hz 230 volt power in a 60Hz world

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mivey

Senior Member
Here's one we made earlier ... Admittedly it's a bit more than 7.5kW and has a few bells and whistles to provide control functions for the specific application.
Well whadda-ya-know, you have mowed this grass before, although on a much larger and more sophisticated level.

Let's suppose you were to make one of these in the 7.5 kW range without all the bells and whistles not needed for the OP's application. What kind of investment are we talking about? $1000's, 10's of $1000 or what? Nothing too precise, just something to get a relative feel for the more elegant solution vs the inverter<->battery bank<->inverter or the simple rotary option.
 

Besoeker

Senior Member
Location
UK
Well whadda-ya-know, you have mowed this grass before, although on a much larger and more sophisticated level.

Let's suppose you were to make one of these in the 7.5 kW range without all the bells and whistles not needed for the OP's application. What kind of investment are we talking about? $1000's, 10's of $1000 or what? Nothing too precise, just something to get a relative feel for the more elegant solution vs the inverter<->battery bank<->inverter or the simple rotary option.
As it happens there are a couple of that rating among a bunch of others in a project we've just been awarded - after about six months of negotiations. Excruciatingly protracted and detailed negotiations I might add. Mostly on technical compliance issues down to the specification for the timber to be used for export packing - there's a 44 page spec on that alone!.....Petrochem projects can be nightmarish in that respect.
Added to the mix is a British supplier, us, a European based customer, Indian consultants, a middle-eastern main contractor.....

I digress. Without giving too many commercial secrets away, the material cost including the metal enclosure, isolators, contactors, terminals, vent fan, hardware, and a bit of control circuitry is around ?2k or $3k.
 

mivey

Senior Member
the material cost including the metal enclosure, isolators, contactors, terminals, vent fan, hardware, and a bit of control circuitry is around ?2k or $3k.
Since she is throwing away about $12 a day in energy (her number), plus more on other maintenance, it seems like the smart thing to do would be to invest in a system like that.
 

Besoeker

Senior Member
Location
UK
Since she is throwing away about $12 a day in energy (her number), plus more on other maintenance, it seems like the smart thing to do would be to invest in a system like that.
Yes, you'd be inclined to think so.
But there will be some objection to it.....
 

Besoeker

Senior Member
Location
UK
I can't imagine. What's up with that?
In a word, consultants.
I think they have to dredge up every specification that might have any relevance to the project, however tenuous that might be.
I even had one that was even longer and specified the angle at which the nails had to be driven in. It might even have given a spec for the nails........
 

mivey

Senior Member
In a word, consultants.
I think they have to dredge up every specification that might have any relevance to the project, however tenuous that might be.
I even had one that was even longer and specified the angle at which the nails had to be driven in. It might even have given a spec for the nails........
Manufacturers are at fault too. Over-specifying is an attempt to cut out the competition. Genericization is a must. Yeah, that's a word.
 

jumper

Senior Member
In a word, consultants.
I think they have to dredge up every specification that might have any relevance to the project, however tenuous that might be.
I even had one that was even longer and specified the angle at which the nails had to be driven in. It might even have given a spec for the nails........

Mine would not only spec the type and size of fastener, but the specific brand/manufacturer and distributer.:D
 

Besoeker

Senior Member
Location
UK
Mine would not only spec the type and size of fastener, but the specific brand/manufacturer and distributer.:D
I've had that but not too often. More often it's instructions on what type of fastener and to how to correctly use/fit it. What type of bolt to use, when/where spring washers/shakeproof washers must be used, how many threads must be visible on the bolt after the nut is done up........you sometimes think hang on a bit Mr Consultant, the customer has awarded us this project and is paying us to make the stuff because we have demonstrated, prior to order, that not only do we know how to make the stuff but have demonstrated that we competent do so to a standard that meets his requirements so why are you in the picture telling us how make things that we have demonstrated we know how to make?
It goes with the territory I suppose.
 
I've had that but not too often. More often it's instructions on what type of fastener and to how to correctly use/fit it. What type of bolt to use, when/where spring washers/shakeproof washers must be used, how many threads must be visible on the bolt after the nut is done up........you sometimes think hang on a bit Mr Consultant, the customer has awarded us this project and is paying us to make the stuff because we have demonstrated, prior to order, that not only do we know how to make the stuff but have demonstrated that we competent do so to a standard that meets his requirements so why are you in the picture telling us how make things that we have demonstrated we know how to make?
It goes with the territory I suppose.

Many times it is overdone, but you have to look back to the origin of how those specifications generated.

One reason is closing the barn-door after the horses have escaped. Somewhere along the line a nut wasn't tightened to specification, there were only 1.5 thread exposed due to the shortness of the bolt, etc.

Second is quality control. Say what you do and do what you say and document it that you've done.

We had an 800HP MV drive failed due to an unchecked/faulty capacitor connection that was hidden and not visible without disassembling some panels. The tech' had a hard time finding it, even thouhg he was demonstrably highly skilled. The drive itself is world class assembly from a/the leading manufacturer. The drive was down for days. The short of it is that there were no recuperable damages, production loss, whereas if a specification had detailed checklist for connections and such records were asked to be furnished, the likeliness of this type failure would have been reduced. I think ISO9000 series went a long way so that you CAN audit the manufacturing QC process and only write into your spec that is missing from their process, but you think is important. Often times during the Factory Audit the Manufacturer will revise their ISO process to accommodate your interest.
 

jumper

Senior Member
I've had that but not too often. More often it's instructions on what type of fastener and to how to correctly use/fit it. What type of bolt to use, when/where spring washers/shakeproof washers must be used, how many threads must be visible on the bolt after the nut is done up........you sometimes think hang on a bit Mr Consultant, the customer has awarded us this project and is paying us to make the stuff because we have demonstrated, prior to order, that not only do we know how to make the stuff but have demonstrated that we competent do so to a standard that meets his requirements so why are you in the picture telling us how make things that we have demonstrated we know how to make?
It goes with the territory I suppose.

Many times it is overdone, but you have to look back to the origin of how those specifications generated.

One reason is closing the barn-door after the horses have escaped. Somewhere along the line a nut wasn't tightened to specification, there were only 1.5 thread exposed due to the shortness of the bolt, etc.

Second is quality control. Say what you do and do what you say and document it that you've done.

We had an 800HP MV drive failed due to an unchecked/faulty capacitor connection that was hidden and not visible without disassembling some panels. The tech' had a hard time finding it, even thouhg he was demonstrably highly skilled. The drive itself is world class assembly from a/the leading manufacturer. The drive was down for days. The short of it is that there were no recuperable damages, production loss, whereas if a specification had detailed checklist for connections and such records were asked to be furnished, the likeliness of this type failure would have been reduced. I think ISO9000 series went a long way so that you CAN audit the manufacturing QC process and only write into your spec that is missing from their process, but you think is important. Often times during the Factory Audit the Manufacturer will revise their ISO process to accommodate your interest.


You two have pretty much summed up the job I landed in. The paper work, QC inspections, detailed specs, ISO9000, etc was a new new world for me.
 

Besoeker

Senior Member
Location
UK
Many times it is overdone, but you have to look back to the origin of how those specifications generated.

One reason is closing the barn-door after the horses have escaped. Somewhere along the line a nut wasn't tightened to specification, there were only 1.5 thread exposed due to the shortness of the bolt, etc.
I agree with that.
What I have also found is what I think amounts a bit of laziness or sloppiness by those who generate the specifications.
A couple of examples. You know that our area is power electronics generally with quite a heavy emphasis on VSDs. We'll get specs that have been clearly written around fixed speed motor starters.

Another real gem was a huge pile of specifications dumped on me after the contract was placed. The guy staggered into my office with a box of papers. It was a box that we get A4 printer paper in, five reams at a time so 2,500 sheets. And it had great wodges of other bumf taped to the outside of it. So we're looking at probably 3,000 plus pages. And specs that referenced others that weren't included. Made "War and Peace" look like a short tale...
Among this lot was a specification on how to write manuals. There was a whole page on the correct use of the comma. I kid you not.

Second is quality control. Say what you do and do what you say and document it that you've done.
Yes. Part of the manufacturing process. Everything documented from detailed mechanical and electrical drawings, factory acceptance tests, site acceptance tests, certificates of conformity for all component parts, certificates of origin.....etc. And all listed in the document dossier.

We had an 800HP MV drive failed due to an unchecked/faulty capacitor connection that was hidden and not visible without disassembling some panels. The tech' had a hard time finding it, even thouhg he was demonstrably highly skilled. The drive itself is world class assembly from a/the leading manufacturer. The drive was down for days. The short of it is that there were no recuperable damages, production loss, whereas if a specification had detailed checklist for connections and such records were asked to be furnished, the likeliness of this type failure would have been reduced.
Again, I agree. In the works we have an inspection procedure that checks all connections and they get marked with a felt tipped pen when they have been. Not foolproof of course - you could have someone on a bad day just marking them off and not checking.

I think ISO9000 series went a long way so that you CAN audit the manufacturing QC process and only write into your spec that is missing from their process, but you think is important. Often times during the Factory Audit the Manufacturer will revise their ISO process to accommodate your interest.

We are ISO9001 certified. The main thing is, as you say, document what you do and demonstrate you do.
Tomorrow we have another quality audit by a different body that we need to keep us on the list for being kept informed of contracts being let in the utility sectors.
 

tallgirl

Senior Member
Location
Great White North
Occupation
Controls Systems firmware engineer
In violation of the Fair Trade Act, unless it is substantiated by interchangeability or availability reasons.

+1

I've had a devil of a time finding the boards I use to manufacture DAQs. Single / sole source is a BAD idea. Really bad.

Make the vendors compete. Find your 2nd and 3rd source that way.
 

hurk27

Senior Member
In violation of the Fair Trade Act, unless it is substantiated by interchangeability or availability reasons.

Does not apply to custom designed equipment:p only equipment pre-designed and offered for sale as advertised in which repair parts must be availble for at least 10 years or used to be, but tell the computer industry that:roll:
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
Does not apply to custom designed equipment:p only equipment pre-designed and offered for sale as advertised in which repair parts must be availble for at least 10 years or used to be, but tell the computer industry that:roll:
I am concerned about systems in the field installed with SatCon inverters.
 
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