Jim On 8/29/2014 2:50 AM, Hypatia's Protégé wrote:
Indeed your difficulty would appear issue of a 'ground-fault' -- With the aim of confirming/eliminating this possibility, please consider exciting the bridge from a line-isolated feed. Moreover employment of a current-limiting resistor (while troubleshooting) would be advisable.Note also that proper operation requires an exciting EMF sufficient to properly bias the string (howbeit this consideration has no bearing upon overheating)Good luck & best regards Dan ----- Original Message ----- From: "dave pierson" <dave_p@xxxxxxxxxxx> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx> Sent: Thursday, August 28, 2014 7:53 PM Subject: Re: [TCML] overheating diode stringsThere is a gotcha with bridge rectifiers, it bit me yaars ago. Borrowing the sketch below: WHERE, if anywhere, are the 'grounds'? ----- Original Message ---Your schematic should look something like the following, with a whole lot more diodes: (AC Input) | |--|>|--|>|--|>|--|--|>|--|>|--|>|--| | | | (-) | (+) | | |--|>|--|>|--|>|--|--|>|--|>|--|>|--| | | | (Negative) (AC Input) (Positive) (output) (Output) I'd guess you have one leg of the bridge turned around.As i understand the test rig, the low/common side of the variac is at 'ground'. IF (note the IF....) the negative output is 'grounded' one string is trying to short the variac wiper to 'ground', half the time. This would not be an issue in the real application, unless the secondary is 'grounded'. best dwp _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla_______________________________________________ Tesla mailing list Tesla@xxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla
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