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References: [ +subject:/^(?:^\s*(re|sv|fwd|fw)[\[\]\d]*[:>-]+\s*)*\[Amps\]\s+Re\:\s+Step\-start\s+calculation\s*$/: 22 ]

Total 22 documents matching your query.

1. [Amps] Re: Step-start calculation (score: 1)
Author: "Roy Koeppe" <royanjoy@ncn.net>
Date: Sat, 20 Nov 2004 07:49:56 -0600
I don't like to think about it. I gives me a headache. 73, Roy K6XK "...What would be a suitable value of step-start R to limit the inrush current to 50A-rms?..." In this practical & real world, it w
/archives//html/Amps/2004-11/msg00323.html (6,776 bytes)

2. Re: [Amps] Re: Step-start calculation (score: 1)
Author: R.Measures <r@somis.org>
Date: Sat, 20 Nov 2004 08:39:32 -0800
Roy -- I calculated that without a step-start R, the inrush-I would be a bit over 1000A -- which is probably enough current to weld the contacts in the power contactor. cheerz. On Nov 20, 2004, at 5:
/archives//html/Amps/2004-11/msg00328.html (8,085 bytes)

3. Re: [Amps] Re: Step-start calculation (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sat, 20 Nov 2004 12:04:32 -0500
PSU designer (http://www.duncanamps.com/psud2/download.html) can do this calculation and I've got it running here. The model needs some values for various parameters. Here's some results for some sam
/archives//html/Amps/2004-11/msg00331.html (9,639 bytes)

4. Re: [Amps] Re: Step-start calculation (score: 1)
Author: R.Measures <r@somis.org>
Date: Sat, 20 Nov 2004 09:43:14 -0800
Jeff -- Here are the needed parameters: C is two, 93uF in a FWD. The mains R is 0.127-ohms, xfmr primary winding R = 0.059-ohms. The transformer sec. potential is 3200V-rms, Rsec = 16.5-ohms. The loa
/archives//html/Amps/2004-11/msg00335.html (10,454 bytes)

5. Re: [Amps] Re: Step-start calculation (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sat, 20 Nov 2004 13:38:04 -0500
Rich... Thanks for the numbers, its educational. The program assumes mains resistance of zero. Since you know the value, it adds to primary winding resistance. Results at 240V in, 2.2M RL, parallel 2
/archives//html/Amps/2004-11/msg00336.html (10,351 bytes)

6. RE: [Amps] Re: Step-start calculation (score: 1)
Author: "Joe Subich, K4IK" <k4ik@subich.com>
Date: Sat, 20 Nov 2004 15:00:20 -0500
Problem is the rectifier is a Full Wave Doubler - not a Full Wave Bridge. Effective capacitance is 93/2 = 46.5 uF. 73, ... Joe, K4IK _______________________________________________ Amps mailing list
/archives//html/Amps/2004-11/msg00338.html (7,756 bytes)

7. Re: [Amps] Re: Step-start calculation (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sat, 20 Nov 2004 16:11:11 -0500
Ok...re-running for full wave doubler Vout = 9010V with bleeders Vout = 7615 to 7395V at 4K load (220V ripple) Ipk turnon = 58 Amps Still a nice power supply Joe Subich, K4IK wrote: Thanks for the nu
/archives//html/Amps/2004-11/msg00339.html (8,601 bytes)

8. Re: [Amps] Re: Step-start calculation (score: 1)
Author: Dennis12Amplify@aol.com
Date: Sun, 21 Nov 2004 13:34:30 EST
** I would guess that because of the large inductance associated with the HV secondary winding, (which would be in series with the secondary resistance and diodes when charging the caps), there could
/archives//html/Amps/2004-11/msg00349.html (7,896 bytes)

9. Re: [Amps] Re: Step-start calculation (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sun, 21 Nov 2004 14:10:17 -0500
Dennis... A transformer has inductance when open circuit, but when something's connected to its secondary, that impedance get transferred to the primary by the square of the turns ratio. So, when the
/archives//html/Amps/2004-11/msg00350.html (9,534 bytes)

10. Re: [Amps] Re: Step-start calculation (score: 1)
Author: Dennis12Amplify@aol.com
Date: Sun, 21 Nov 2004 14:54:45 EST
A transformer has inductance when open circuit, but when something's connected to its secondary, that impedance get transferred to the primary by the square of the turns ratio. So, when the transform
/archives//html/Amps/2004-11/msg00351.html (9,904 bytes)

11. Re: [Amps] Re: Step-start calculation (score: 1)
Author: w5ca <chisholm@tca.net>
Date: Sun, 21 Nov 2004 15:11:15 -0600
One situation I don't recall being discussed is a choke input filter. It appears the "inrush" current to the rectifier/filter network should be greatly reduced by the choke.?? Al W5CA _______________
/archives//html/Amps/2004-11/msg00352.html (8,053 bytes)

12. Re: [Amps] Re: Step-start calculation (score: 1)
Author: Will Matney <craxd1@ezwv.com>
Date: Sun, 21 Nov 2004 16:53:35 -0500
I thought I ought to give a link to the following PDF file by Potter & Brumfield about the effects of using a zero-crossover switch with transformers. From this, I think most will see how and why sur
/archives//html/Amps/2004-11/msg00354.html (11,507 bytes)

13. Re: [Amps] Re: Step-start calculation (score: 1)
Author: R.Measures <r@somis.org>
Date: Sun, 21 Nov 2004 14:41:59 -0800
On Nov 21, 2004, at 10:34 AM, Dennis12Amplify@aol.com wrote: In a message dated 11/20/04 11:47:47 AM Central Standard Time, r@somis.org writes: I do not see how this computer app. could calculate inr
/archives//html/Amps/2004-11/msg00355.html (9,478 bytes)

14. Re: [Amps] Re: Step-start calculation (score: 1)
Author: R.Measures <r@somis.org>
Date: Sun, 21 Nov 2004 14:50:52 -0800
Al -- For a SSB linear-amplifier PS, the choke must be resonated with a capacitor, so the rectifiers are typically driving c. 0.2uF of input-C. This would probably make the inrush-I slightly higher t
/archives//html/Amps/2004-11/msg00356.html (8,582 bytes)

15. Re: [Amps] Re: Step-start calculation (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sun, 21 Nov 2004 18:31:06 -0500
Will... Wow...that's a scary paper. But, I just don't understand it. ...And the calculations don't make sense. For example, the paper insists that zero voltage switching will cause horrible problems
/archives//html/Amps/2004-11/msg00358.html (13,489 bytes)

16. Re: [Amps] Re: Step-start calculation (score: 1)
Author: R.Measures <r@somis.org>
Date: Sun, 21 Nov 2004 15:54:20 -0800
On Nov 21, 2004, at 3:31 PM, jeff millar wrote: Will... Wow...that's a scary paper. But, I just don't understand it. ...And the calculations don't make sense. For example, the paper insists that zero
/archives//html/Amps/2004-11/msg00360.html (8,996 bytes)

17. Re: [Amps] Re: Step-start calculation (score: 1)
Author: Will Matney <craxd1@ezwv.com>
Date: Sun, 21 Nov 2004 19:28:09 -0500
Jeff, I think what they're talking about is the core saturating during the first few 1/2 cycles. When this happens, there is little inductance and thus no impedance except the DC resistance of the wi
/archives//html/Amps/2004-11/msg00362.html (15,947 bytes)

18. Re: [Amps] Re: Step-start calculation (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sun, 21 Nov 2004 20:07:01 -0500
Will...Indeed that's what it says. But what's all this stuff about magnetizing current in transformers?? Someone needs to explain that effect. The paper seems to say that a transformer with nothing c
/archives//html/Amps/2004-11/msg00363.html (11,699 bytes)

19. [Amps] Re: Step-start calculation (score: 1)
Author: <exray@bellsouth.net>
Date: Sun, 21 Nov 2004 21:29:20 -0500
Jeff' The magnitude of the current depends a great deal on the transformer type....for instance a fair size torroid, say 1 or 2 KVA will absolutely require some form of current limiting or you WILL t
/archives//html/Amps/2004-11/msg00364.html (8,055 bytes)

20. Re: [Amps] Re: Step-start calculation (score: 1)
Author: Tomm Aldridge <KD7QAE@ARRL.NET>
Date: Mon, 22 Nov 2004 03:55:41 +0000
All, Transformers frequently have a gap in the core just to prevent the flux walking behavior described in the article. The reason tape wound toroid cored transformers behave so badly in this regard
/archives//html/Amps/2004-11/msg00365.html (9,977 bytes)

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