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Title: Crown / qsc universal power supply and 240 split phase
Post by: joseph baio on September 12, 2017, 09:24:51 AM
Is it possible I can use the crown itech hd amps and qsc pld  4.5 on 240 volt us  split phase.  Thanks joey
Title: Re: Crown / qsc universal power supply and 240 split phase
Post by: Tony Mamoh on September 15, 2017, 05:10:09 PM
Is it possible I can use the crown itech hd amps and qsc pld  4.5 on 240 volt us  split phase.  Thanks joey

Just check the rear of the power amp, near the IEC power cable and you will be able to read the power rating to confirm if it's universal voltage rating. However I suspect you don't have the amp presently and need to reconfirm with users. That leaves you with no option but to check the online manual. I can look that up for you in a few days when I am free.
Title: Re: Crown / qsc universal power supply and 240 split phase
Post by: Tim McCulloch on September 15, 2017, 05:19:49 PM
Is it possible I can use the crown itech hd amps and qsc pld  4.5 on 240 volt us  split phase.  Thanks joey
Crown I TECH will accept line voltage from 90 to 250V. at 50 or 60 Hz. I am not familiar with the QSC power needs but that is a spec sheet item.   If you can post to this forum you should be able to get a spec sheet online....
Title: Re: Crown / qsc universal power supply and 240 split phase
Post by: joseph baio on September 17, 2017, 03:45:13 PM
Crown I TECH will accept line voltage from 90 to 250V. at 50 or 60 Hz. I am not familiar with the QSC power needs but that is a spec sheet item.   If you can post to this forum you should be able to get a spec sheet online....
  Thanks for your response! I am seeking clarification as to split phase operation. I do have crown itech hd amps in main racks as well as a qsc 4.5 in the monitor rack and nowhere in the manual does it explain split phase connection. I am looking to reduce the current load by racks being able to reduce mains cable size and all associated power cabling.
  As I understand it USA 240v is 120v on each leg out of phase plus ground so can I feed two hot legs plus ground to the amps or am I only able to send 90-250v on the hot leg with neutral and ground being what it is.             thanks again joey
Title: Re: Crown / qsc universal power supply and 240 split phase
Post by: William Schnake on September 17, 2017, 05:05:21 PM
  As I understand it USA 240v is 120v on each leg out of phase plus ground so can I feed two hot legs plus ground to the amps or am I only able to send 90-250v on the hot leg with neutral and ground being what it is.             thanks again joey
Joey, in the US, you would have to have two hot legs and a ground in order to make this work.  Someone please correct me if I am wrong, however I am sure that I am 2.5 percent sure I am correct.

Bill
Title: Re: Crown / qsc universal power supply and 240 split phase
Post by: joseph baio on September 17, 2017, 07:10:04 PM
Joey, in the US, you would have to have two hot legs and a ground in order to make this work.  Someone please correct me if I am wrong, however I am sure that I am 2.5 percent sure I am correct.

Bill
Bill
   Thats what im asking if I can send 2 hot legs of 120v plus a ground to the amps so ill get a total of 240v.  I just dont see anywhere in the manual where on how to do this. It would be great   joey
Title: Re: Crown / qsc universal power supply and 240 split phase
Post by: Scott Holtzman on September 17, 2017, 09:05:04 PM
Bill
   Thats what im asking if I can send 2 hot legs of 120v plus a ground to the amps so ill get a total of 240v.  I just dont see anywhere in the manual where on how to do this. It would be great   joey

Oh, I think I understand what you are asking.  There are no "single 120's to make a 240'  The Neutral is derivived from a center tap on the transformer.  The power on the entrance is single phase 240v, one winding of a transformer.  the power is phase to phase with each leg alternating 60 times a second.  There is no neutral in 240.

I am sure this is more confusing and someone will have a better explanation than I however for wiring purposes the IEC (if so equipped) on the amp will have the two legs go to the output windings of the transformer feeding the panel.

Title: Re: Crown / qsc universal power supply and 240 split phase
Post by: William Schnake on September 17, 2017, 09:11:19 PM
You would have to be on a 240 volt system not two 120 volt systems.  I believe that you would wire it as follows:

Black to Brass - 1st leg of 120 from a single phase 240 volt system
White to Silver - 2nd leg of 120 volts from a single phase 240 volt system
Green - Ground of the system

The key here is that you are not using two 120 volt lines you are using a 240 volt services with two hot lines.

Bill
Title: Re: Crown / qsc universal power supply and 240 split phase
Post by: Scott Holtzman on September 17, 2017, 09:21:23 PM
You would have to be on a 240 volt system not two 120 volt systems.  I believe that you would wire it as follows:

Black to Brass - 1st leg of 120 from a single phase 240 volt system
White to Silver - 2nd leg of 120 volts from a single phase 240 volt system
Green - Ground of the system

The key here is that you are not using two 120 volt lines you are using a 240 volt services with two hot lines.

Bill

Bill, that's my point, thinking about it as a leg of 120V is not right.  It's just the output of a 240V step down transformer.  120V only comes into play when the neutral line is used as a reference.  The neutral is a center tap of the 240V single phase service which is comprised of two wires. Ground is also not a reference but a safety.  Without a neutral to ground bond you would not have 120V to ground.

 
Title: Re: Crown / qsc universal power supply and 240 split phase
Post by: William Schnake on September 18, 2017, 08:54:54 AM
It's just the output of a 240V step down transformer.  120V only comes into play when the neutral line is used as a reference.  The neutral is a center tap of the 240V single phase service which is comprised of two wires. Ground is also not a reference but a safety.  Without a neutral to ground bond you would not have 120V to ground.

Agreed Scott.  Now where is drape for my 18" and 24" decks???

Bill
Title: Re: Crown / qsc universal power supply and 240 split phase
Post by: Scott Holtzman on September 18, 2017, 05:37:43 PM
Agreed Scott.  Now where is drape for my 18" and 24" decks???

Bill

That's right, you wanted the the ripped drape to make some skirts out of....

The season's over....We are in shop cleaning mode after this weekend, how many linear feet did you need?

Title: Re: Crown / qsc universal power supply and 240 split phase
Post by: William Schnake on September 18, 2017, 06:11:24 PM
That's right, you wanted the the ripped drape to make some skirts out of....

The season's over....We are in shop cleaning mode after this weekend, how many linear feet did you need?
Scott, 108 linear ft 18" if possible.

Thanks
Title: Re: Crown / qsc universal power supply and 240 split phase
Post by: joseph baio on September 18, 2017, 08:08:37 PM
You would have to be on a 240 volt system not two 120 volt systems.  I believe that you would wire it as follows:

Black to Brass - 1st leg of 120 from a single phase 240 volt system
White to Silver - 2nd leg of 120 volts from a single phase 240 volt system
Green - Ground of the system

The key here is that you are not using two 120 volt lines you are using a 240 volt services with two hot lines.

Bill
Thanks for the clarification, I think my verbiage is in error. I understand the use of 240v USA and just making sure because as I understand it in Europe the 220v is delivered on one leg and I want to verify the amps can take the 240v across 2 hot legs and not a universal voltage single hot leg. I spoke to QSC earlier and they verified the pld 4.5 will do 240v USA. I assume Crown I-tech HD will follow suit.  thanks much, joey
Title: Re: Crown / qsc universal power supply and 240 split phase
Post by: Scott Holtzman on September 18, 2017, 11:55:35 PM
Thanks for the clarification, I think my verbiage is in error. I understand the use of 240v USA and just making sure because as I understand it in Europe the 220v is delivered on one leg and I want to verify the amps can take the 240v across 2 hot legs and not a universal voltage single hot leg. I spoke to QSC earlier and they verified the pld 4.5 will do 240v USA. I assume Crown I-tech HD will follow suit.  thanks much, joey

Mike Sokol, can you step in here and clarify please.  I think we are talking semantics, current has to return somewhere.  Euro 220v has the center tap bonded to ground.  the potential between the two wires is still 220v

I only see an issue on really old gear that has a single pole switch on the mains.

Title: Re: Crown / qsc universal power supply and 240 split phase
Post by: Barry Singleton on September 19, 2017, 12:52:17 AM
The I-TECH will happily run on Americas 240V single phase/ 120-120V.

All it really cares about is having a 50-60 Hz voltage differential accross the two line pins of 90-240V. Being on the high side of this is better if your running hard.

Barry.
Title: Re: Crown / qsc universal power supply and 240 split phase
Post by: Daniel Levi on September 19, 2017, 03:43:22 AM
Ground/Neutral is irrelevant here in order for current to flow there needs to be a potential difference.
In a regular 220/230/240v system you have a 240v RMS leg/conductor and a 0V leg/conductor naturally with a potential difference of 240V RMS. The fact that the 2nd leg/conductor is 0V doesn't matter, so long as it is different to the 1st leg/conductor current will flow.

In the 2 phase system you are still getting a potential difference of 240V RMS in regards to the 2 legs/conductors it's just that rather that one leg/conductor being at 0v it is at 120° out of phase with the 1st conductor, this means that when the 1st leg is at +120V RMS the 2nd leg is at -120V RMS creating the required potential difference of 240V RMS.

The tube network in London uses a DC version of the same sort of thing and also has no direct earth and trains designed for +750/630V - 0 work just fine on +210 - -420.   
Title: Re: Crown / qsc universal power supply and 240 split phase
Post by: Barry Singleton on September 19, 2017, 09:14:13 AM
....In the 2 phase system you are still getting a potential difference of 240V RMS in regards to the 2 legs/conductors it's just that rather that one leg/conductor being at 0v it is at 120° out of phase with the 1st conductor, this means that when the 1st leg is at +120V RMS the 2nd leg is at -120V RMS creating the required potential difference of 240V RMS...

The above describes two legs of a three phase system. The 120-120V combined voltage at 120 degrees phase will be 208V

120-120V at 180 degrees phase (single phase) will be 240V.

Either work fine. :)

Barry.