CAD CAM EDM DRO - Yahoo Group Archive

Re: [CAD_CAM_EDM_DRO] Re: What size capacitor should I use? resistors....

Posted by Jon Elson
on 2005-01-26 22:33:41 UTC
cnc_4_me wrote:

>
>
>>I understand the desire to limit the starting inrush current as
>>
>>
>well
>
>
>>as the need for the smallest time constant.
>>
>>would it not be prudent to charge the cap slowly up to some value,
>>and at that point, switch over to the raw voltage directly ?
>>
>>It would seem a simple electromechanical relay would be a
>>
>>
>possibliity
>
>
>>to eleminate the hum of initial power on.
>>
>>Dave
>>
>>
>
>You are exactly right dave...And for a example Jon Elson used to have
>on his site a schematic of what you just described (not sure if it is
>still there). He used a time delay relay to slowly charge the caps...
>
>This method also helps save the bridge rectifier from the huge
>inrush...I usally spec the bridge rectifier current rating 50 to 100%
>larger than desired current because of this huge inrush...
>
>
Actually, that circuit is to reduce the inrush when a big DC supply is
connected to
the smaller caps in a bank of servo amps. Connecting two caps at
different voltages
with a big relay is one way to define a spot welder! But, the circuit
is about
the same.

The transformer limits the inrush a bit due to leakage inductance. If
you just rectify
the line directly, the inrush can reach 4000 A! Power Switches don't
handle too
many surges like that. With a big transformer, the surges may only
reach 400 A
or so, but that can still kill the rectifier and power switch after a while.

Jon

Discussion Thread

rllalonde2000 2005-01-26 04:28:01 UTC What size capacitor should I use? A. G. Eckstein 2005-01-26 04:58:31 UTC Re: [CAD_CAM_EDM_DRO] What size capacitor should I use? Simon Arthur 2005-01-26 05:38:23 UTC Re: [CAD_CAM_EDM_DRO] What size capacitor should I use? R Rogers 2005-01-26 06:56:31 UTC Re: [CAD_CAM_EDM_DRO] What size capacitor should I use? Terrenoire, Adrien L 2005-01-26 07:00:14 UTC Re: [CAD_CAM_EDM_DRO] What size capacitor should I use? Andy Wander 2005-01-26 07:01:23 UTC RE: [CAD_CAM_EDM_DRO] What size capacitor should I use? turbulatordude 2005-01-26 07:07:50 UTC Re: What size capacitor should I use? - voltage ? A. G. Eckstein 2005-01-26 07:13:30 UTC Re: [CAD_CAM_EDM_DRO] What size capacitor should I use? caudlet 2005-01-26 08:00:51 UTC Re: What size capacitor should I use? Bengt 2005-01-26 09:11:26 UTC Re: What size capacitor should I use? Jon Elson 2005-01-26 09:28:27 UTC Re: [CAD_CAM_EDM_DRO] What size capacitor should I use? Roy J. Tellason 2005-01-26 09:44:34 UTC Re: [CAD_CAM_EDM_DRO] What size capacitor should I use? turbulatordude 2005-01-26 09:58:26 UTC Re: What size capacitor should I use? Andy Wander 2005-01-26 10:19:07 UTC RE: [CAD_CAM_EDM_DRO] Re: What size capacitor should I use? caudlet 2005-01-26 11:29:56 UTC Re: What size capacitor should I use? Roy J. Tellason 2005-01-26 11:41:56 UTC Re: [CAD_CAM_EDM_DRO] Re: What size capacitor should I use? Rob Polley 2005-01-26 11:43:12 UTC Looking for advice Dan Mauch 2005-01-26 12:18:29 UTC Re: [CAD_CAM_EDM_DRO] Looking for advice Codesuidae 2005-01-26 12:34:15 UTC Re: [CAD_CAM_EDM_DRO] Looking for advice victorlorenzo@y... 2005-01-26 12:55:47 UTC Re: Looking for advice Stephen Wille Padnos 2005-01-26 13:38:53 UTC Re: [CAD_CAM_EDM_DRO] Re: What size capacitor should I use? John 2005-01-26 14:04:29 UTC Re: [CAD_CAM_EDM_DRO] Re: What size capacitor should I use? Simon Arthur 2005-01-26 14:09:40 UTC Re: [CAD_CAM_EDM_DRO] What size capacitor should I use? erie 2005-01-26 14:33:11 UTC Re: [CAD_CAM_EDM_DRO] Re: What size capacitor should I use? Stephen Wille Padnos 2005-01-26 14:37:28 UTC Re: [CAD_CAM_EDM_DRO] What size capacitor should I use? R Rogers 2005-01-26 14:56:53 UTC [CAD_CAM_EDM_DRO] Toroidal transformer ratings?? Amps? Kv? Kva? JanRwl@A... 2005-01-26 15:04:42 UTC Re: [CAD_CAM_EDM_DRO] What size capacitor should I use? Les Newell 2005-01-26 15:05:07 UTC Re: [CAD_CAM_EDM_DRO] Toroidal transformer ratings?? Amps? Kv? Kva? cnc_4_me 2005-01-26 15:08:24 UTC Re: What size capacitor should I use? David Paulson 2005-01-26 15:10:21 UTC Re: [CAD_CAM_EDM_DRO] Toroidal transformer ratings?? Amps? Kv? Kva? cnc_4_me 2005-01-26 15:23:15 UTC Re: Toroidal transformer ratings?? Amps? Kv? Kva? JanRwl@A... 2005-01-26 15:40:19 UTC Re: [CAD_CAM_EDM_DRO] Re: What size capacitor should I use? R Rogers 2005-01-26 15:49:48 UTC Re: [CAD_CAM_EDM_DRO] Toroidal transformer ratings?? What after being rectified? cnc_4_me 2005-01-26 15:55:58 UTC Re: What size capacitor should I use? cnc_4_me 2005-01-26 16:14:14 UTC Re: Toroidal transformer ratings?? What after being rectified? R Rogers 2005-01-26 16:18:19 UTC Re: [CAD_CAM_EDM_DRO] Re: What size capacitor should I use?sizing supply Ron Ginger 2005-01-26 17:01:36 UTC Re: Looking for advice polaraligned 2005-01-26 17:09:38 UTC What size capacitor should I use? Polaraligned 2005-01-26 17:25:09 UTC Re: Toroidal transformer ratings?? Amps? Kv? Kva? R Rogers 2005-01-26 17:29:00 UTC Re: [CAD_CAM_EDM_DRO] Re: Looking for advice cnc_4_me 2005-01-26 18:05:05 UTC Re: What size capacitor should I use? victorlorenzo@y... 2005-01-26 18:19:00 UTC Re: Looking for advice codeSuidae 2005-01-26 18:32:59 UTC Re: [CAD_CAM_EDM_DRO] Re: What size capacitor should I use? cnc_4_me 2005-01-26 18:54:06 UTC Re: What size capacitor should I use? Ken Langston 2005-01-26 18:56:05 UTC Re: [CAD_CAM_EDM_DRO] Re: Toroidal transformer ratings?? Amps? Kv? Kva? cnc_4_me 2005-01-26 19:01:47 UTC Re: Toroidal transformer ratings?? Amps? Kv? Kva? Rob Polley 2005-01-26 19:24:26 UTC Re: [CAD_CAM_EDM_DRO] Re: Looking for advice codeSuidae 2005-01-26 19:26:51 UTC Re: [CAD_CAM_EDM_DRO] Re: What size capacitor should I use? cnc_4_me 2005-01-26 19:35:49 UTC Re: Looking for advice bobmcknight@c... 2005-01-26 19:37:07 UTC Re: [CAD_CAM_EDM_DRO] Re: Toroidal transformer ratings?? Amps? Kv? Kva? bobmcknight@c... 2005-01-26 19:37:08 UTC Re: [CAD_CAM_EDM_DRO] Re: What size capacitor should I use? cnc_4_me 2005-01-26 19:54:55 UTC Re: What size capacitor should I use? turbulatordude 2005-01-26 19:57:22 UTC Re: What size capacitor should I use? resistors.... cnc_4_me 2005-01-26 20:08:00 UTC Re: What size capacitor should I use? resistors.... JanRwl@A... 2005-01-26 21:34:22 UTC Re: [CAD_CAM_EDM_DRO] What size capacitor should I use? JanRwl@A... 2005-01-26 21:43:19 UTC Re: [CAD_CAM_EDM_DRO] Toroidal transformer ratings?? Amps? Kv? Kva? codeSuidae 2005-01-26 21:56:30 UTC Re: [CAD_CAM_EDM_DRO] Re: What size capacitor should I use? Jon Elson 2005-01-26 21:56:33 UTC Re: [CAD_CAM_EDM_DRO] Toroidal transformer ratings?? What after being rectified? Mariss Freimanis 2005-01-26 21:58:04 UTC Re: What size capacitor should I use? resistors.... Jon Elson 2005-01-26 22:08:03 UTC Re: [CAD_CAM_EDM_DRO] Re: What size capacitor should I use? JanRwl@A... 2005-01-26 22:09:14 UTC Re: [CAD_CAM_EDM_DRO] Re: Looking for advice Jon Elson 2005-01-26 22:22:35 UTC Re: [CAD_CAM_EDM_DRO] Re: Toroidal transformer ratings?? Amps? Kv? Kva? Jon Elson 2005-01-26 22:29:43 UTC Re: [CAD_CAM_EDM_DRO] Re: What size capacitor should I use? resistors.... Jon Elson 2005-01-26 22:33:41 UTC Re: [CAD_CAM_EDM_DRO] Re: What size capacitor should I use? resistors.... Simon Arthur 2005-01-27 00:01:53 UTC Re: [CAD_CAM_EDM_DRO] What size capacitor should I use? Polaraligned 2005-01-27 04:15:31 UTC Re: What size capacitor should I use? Polaraligned 2005-01-27 04:29:29 UTC Re: Toroidal transformer ratings?? What after being rectified? turbulatordude 2005-01-27 06:26:30 UTC Re: What size capacitor should I use? resistor or not ?? turbulatordude 2005-01-27 06:45:41 UTC Re: Toroidal transformer ratings?? What after being rectified? Leslie Watts 2005-01-27 07:04:52 UTC RE: [CAD_CAM_EDM_DRO] Re: Toroidal transformer ratings?? What after being rectified? Jon Elson 2005-01-27 10:30:37 UTC Re: [CAD_CAM_EDM_DRO] Re: Toroidal transformer ratings?? What after being rectified? Jon Elson 2005-01-27 10:40:20 UTC Re: [CAD_CAM_EDM_DRO] Re: What size capacitor should I use? resistor or not ?? cnc_4_me 2005-01-27 10:47:17 UTC Re: Toroidal transformer ratings?? What after being rectified? Les Newell 2005-01-27 12:49:45 UTC Re: [CAD_CAM_EDM_DRO] Re: Toroidal transformer ratings?? What after being rectified? Polaraligned 2005-01-27 13:39:18 UTC Re: Toroidal transformer ratings?? What after being rectified? Stephen Wille Padnos 2005-01-27 14:44:25 UTC Re: [CAD_CAM_EDM_DRO] Re: Toroidal transformer ratings?? What after being rectified? Polaraligned 2005-01-27 18:13:16 UTC Re: Toroidal transformer ratings?? What after being rectified? Steve Stallings 2005-01-27 18:18:44 UTC Re: Toroidal transformer ratings?? What after being rectified? Stephen Wille Padnos 2005-01-27 18:28:46 UTC Re: [CAD_CAM_EDM_DRO] Re: Toroidal transformer ratings?? What after being rectified? Jon Elson 2005-01-27 21:35:23 UTC Re: [CAD_CAM_EDM_DRO] Re: Toroidal transformer ratings?? What after being rectified? Kevin Martin 2005-01-28 05:32:28 UTC RE: [CAD_CAM_EDM_DRO] Re: Toroidal transformer ratings?? What after being rectified? m0nkey0ne 2005-01-28 11:22:47 UTC Re: Toroidal transformer ratings?? What after being rectified? Mcginnis, Darrell S 2005-03-22 14:43:20 UTC RE: [CAD_CAM_EDM_DRO] What size capacitor should I use?