pradeeba Posted May 11, 2007 Report Share Posted May 11, 2007 how to select the value of fusible resistor Quote Link to comment Share on other sites More sharing options...
esp1 Posted May 11, 2007 Report Share Posted May 11, 2007 hi,Your question is like asking what size fuse shall I use??Its not possible to suggest a 'fusible link' without knowing more of the application.If possible, post a drawing of the circuit you want to protect. Quote Link to comment Share on other sites More sharing options...
pradeeba Posted May 14, 2007 Author Report Share Posted May 14, 2007 sorry I cant post the schematics. can u tel me is there any formula to calculate fusible resistor. end application is battery charger. and can u tel me the relation between the peak primary current? Quote Link to comment Share on other sites More sharing options...
esp1 Posted May 14, 2007 Report Share Posted May 14, 2007 hi,I would not normally fit a fusible resistor in a battery charger, a standard, slow blow fuse would be OK.If its a typical battery charger I would expect a 5 or 10Amp fuse would be OK.Does the battery charger have a current meter??>> relation between the peak primary current?I'm not sure what you are comparing with peak primary current???? Quote Link to comment Share on other sites More sharing options...
pradeeba Posted May 15, 2007 Author Report Share Posted May 15, 2007 output power is 1.25W. we used 10E,1w fusible resistor. it got blowed & diode in the bridge rectifier connected in the neutral path also got blowed.then we used 20E,1W fusible resistor, again same thing happened. can u assist me what to do further? ther e is no current meter. my question was is there any relation b/w primary peak current to choose the value of fusible resistor or fuse. if not how to calculate fuse value. Quote Link to comment Share on other sites More sharing options...
esp1 Posted May 15, 2007 Report Share Posted May 15, 2007 output power is 1.25W. we used 10E,1w fusible resistor. it got blowed & diode in the bridge rectifier connected in the neutral path also got blowed.then we used 20E,1W fusible resistor, again same thing happened. can u assist me what to do further? ther e is no current meter. my question was is there any relation b/w primary peak current to choose the value of fusible resistor or fuse. if not how to calculate fuse value.Hi,If its blowing the bridge rectifier, the problems not with the fuse link. I would suspect you have a short on the output of the charger. Have you tested across the output terminals with a ohms meter. [ WITH THE MAINS POWER DISCONNECTED] ???Also, does it blow fuses when no battery is connected to the output??Also, is the charger rated at the same voltage as the battery, example: 12Vcharger, 12Vbattery??Also, is the input mains selection for the transformer set for you local mains supply voltage??? Quote Link to comment Share on other sites More sharing options...
pradeeba Posted May 15, 2007 Author Report Share Posted May 15, 2007 hi,Actually there are 8 boards. 6 are working fine. only 2 boards are giving the problem. fuse blows when no battery is connected to the output. power suuply o/p is 5V & battery for battery 3.6V is needed. :) Quote Link to comment Share on other sites More sharing options...
esp1 Posted May 15, 2007 Report Share Posted May 15, 2007 The 2 boards that are blowing fuses, have you done a resistance check on the output pins.I sounds as though you have short on the boards, especially as they blow with no battery connected.Do you have a circuit you can post, it will make it easier to suggest a repair.Are the 3.6 Vbty for mobile phones? Quote Link to comment Share on other sites More sharing options...
ante Posted May 21, 2007 Report Share Posted May 21, 2007 Are the output connectors switched? Quote Link to comment Share on other sites More sharing options...
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