Topband: AC line bypass capacitors
My 160 TX is causing RFI to one of my baseboard heater programmable thermostats (switches modes, temperature, when I transmit). The thermostat has a 2 wire connection to 240VAC in a metal receptacle box that has a third wire common ground wire. I would like to try bypassing the AC line. Can someone suggest an appropriate (safe) capacitor for this purpose, e.g. a Digi-Key or Mouser part number? Should I use one capacitor across the 240VAC or two capacitors, one from each 120VAC line to the common wire? Thanks for the help. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: AC line bypass capacitors
My 160 TX is causing RFI to one of my baseboard heater programmable thermostats (switches modes, temperature, when I transmit). The thermostat has a 2 wire connection to 240VAC in a metal receptacle box that has a third wire common ground wire. I would like to try bypassing the AC line. Can someone suggest an appropriate (safe) capacitor for this purpose, e.g. a Digi-Key or Mouser part number? Should I use one capacitor across the 240VAC or two capacitors, one from each 120VAC line to the common wire? Thanks for the help. _ As a substitute for X1 Y2 line caps, an in-line RFI/EMI filter can be used that already contains the X/Y-rated caps. See the bottom of p. 21: http://audiosystemsgroup.com/RFI-Ham.pdf These filters can often be cannibalized from old PC power supplies and discarded industrial equipment. Paul, W9AC _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: AC line bypass capacitors
My 160 TX is causing RFI to one of my baseboard heater programmable thermostats (switches modes, temperature, when I transmit). The thermostat has a 2 wire connection to 240VAC in a metal receptacle box that has a third wire common ground wire. I would like to try bypassing the AC line. Can someone suggest an appropriate (safe) capacitor for this purpose, e.g. a Digi-Key or Mouser part number? Should I use one capacitor across the 240VAC or two capacitors, one from each 120VAC line to the common wire? Thanks for the help. _ The safest bypass method for 120V is to put one 250 VAC rated cap across the line, and one more cap from neutral to safety ground. The safest method for 240V would be to use two caps, one from each 120 to neutral. Then use a single cap from neutral to safety ground if it exists. This method ensures you do not screw up any GFI stuff, and if a cap faults it faults from a hot directly to a current carrying return and not into a safety system. The caps are UL VDE CSA rated line bypasses, available from Mouser and others. I would use a 0.01 uF capacitor. They are about ten ohms on 160 meters, if I remember right. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: AC line bypass capacitors
Hi, Harold - well it's been a while, I know that we regularly used line bypasses in electricity meter and they had to be really robust, but I was mostly and RF and communications guy and when I had to fool with power supply designs for the meters, I generally just copied whatever was done before. Of course out there on the line side of the meter is a hellish surge environment. On guy mentioned film capacitors, but I would be a bit skeptical of those as RF bypasses. The capacitors that we used were very robust, as they had to withstand 480 volt high-line voltage or 530 VAC. And yes I have seen my share of fried line bypass capacitors in consumer electronics and radio gear. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of HAROLD SMITH JR Sent: Wednesday, February 04, 2015 9:16 PM To: Charlie Cunningham; 'Paul Christensen'; topband@contesting.com Subject: Re: Topband: AC line bypass capacitors Hi Charlie, I can remember when the Collins S-Line used .01 600volt disk ceramic capacitors on the power supply connector. They were from the AC switch to ground. They were almost always burnt and many times only the leads left. 73 Price W0RI On Wednesday, February 4, 2015 6:31 PM, Charlie Cunningham charlie-cunning...@nc.rr.com wrote: Hi, Paul For AC line bypass capacitors look for UL-rated Ceramic Disc capacitors that typically have AC working voltages like 250 VAC or higher. These are designed and rated for AC line service and can take the surges that occur on AC lines. Check Digi-Key, Newark and others - you'll find plenty! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Paul Christensen Sent: Wednesday, February 04, 2015 3:55 PM To: topband@contesting.com Subject: Re: Topband: AC line bypass capacitors My 160 TX is causing RFI to one of my baseboard heater programmable thermostats (switches modes, temperature, when I transmit). The thermostat has a 2 wire connection to 240VAC in a metal receptacle box that has a third wire common ground wire. I would like to try bypassing the AC line. Can someone suggest an appropriate (safe) capacitor for this purpose, e.g. a Digi-Key or Mouser part number? Should I use one capacitor across the 240VAC or two capacitors, one from each 120VAC line to the common wire? Thanks for the help. _ As a substitute for X1 Y2 line caps, an in-line RFI/EMI filter can be used that already contains the X/Y-rated caps. See the bottom of p. 21: http://audiosystemsgroup.com/RFI-Ham.pdf These filters can often be cannibalized from old PC power supplies and discarded industrial equipment. Paul, W9AC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: AC line bypass capacitors
Hi, Paul For AC line bypass capacitors look for UL-rated Ceramic Disc capacitors that typically have AC working voltages like 250 VAC or higher. These are designed and rated for AC line service and can take the surges that occur on AC lines. Check Digi-Key, Newark and others - you'll find plenty! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Paul Christensen Sent: Wednesday, February 04, 2015 3:55 PM To: topband@contesting.com Subject: Re: Topband: AC line bypass capacitors My 160 TX is causing RFI to one of my baseboard heater programmable thermostats (switches modes, temperature, when I transmit). The thermostat has a 2 wire connection to 240VAC in a metal receptacle box that has a third wire common ground wire. I would like to try bypassing the AC line. Can someone suggest an appropriate (safe) capacitor for this purpose, e.g. a Digi-Key or Mouser part number? Should I use one capacitor across the 240VAC or two capacitors, one from each 120VAC line to the common wire? Thanks for the help. _ As a substitute for X1 Y2 line caps, an in-line RFI/EMI filter can be used that already contains the X/Y-rated caps. See the bottom of p. 21: http://audiosystemsgroup.com/RFI-Ham.pdf These filters can often be cannibalized from old PC power supplies and discarded industrial equipment. Paul, W9AC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: AC line bypass capacitors
Hi Charlie, I can remember when the Collins S-Line used .01 600volt disk ceramic capacitors on the power supply connector. They were from the AC switch to ground. They were almost always burnt and many times only the leads left. 73 Price W0RI On Wednesday, February 4, 2015 6:31 PM, Charlie Cunningham charlie-cunning...@nc.rr.com wrote: Hi, Paul For AC line bypass capacitors look for UL-rated Ceramic Disc capacitors that typically have AC working voltages like 250 VAC or higher. These are designed and rated for AC line service and can take the surges that occur on AC lines. Check Digi-Key, Newark and others - you'll find plenty! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Paul Christensen Sent: Wednesday, February 04, 2015 3:55 PM To: topband@contesting.com Subject: Re: Topband: AC line bypass capacitors My 160 TX is causing RFI to one of my baseboard heater programmable thermostats (switches modes, temperature, when I transmit). The thermostat has a 2 wire connection to 240VAC in a metal receptacle box that has a third wire common ground wire. I would like to try bypassing the AC line. Can someone suggest an appropriate (safe) capacitor for this purpose, e.g. a Digi-Key or Mouser part number? Should I use one capacitor across the 240VAC or two capacitors, one from each 120VAC line to the common wire? Thanks for the help. _ As a substitute for X1 Y2 line caps, an in-line RFI/EMI filter can be used that already contains the X/Y-rated caps. See the bottom of p. 21: http://audiosystemsgroup.com/RFI-Ham.pdf These filters can often be cannibalized from old PC power supplies and discarded industrial equipment. Paul, W9AC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: AC line bypass capacitors
Digikey carries Panasonic's line of ac Lin filter caps. They are Sent from my iPhone On Feb 4, 2015, at 12:52 PM, Roger Graves ve...@shaw.ca wrote: My 160 TX is causing RFI to one of my baseboard heater programmable thermostats (switches modes, temperature, when I transmit). The thermostat has a 2 wire connection to 240VAC in a metal receptacle box that has a third wire common ground wire. I would like to try bypassing the AC line. Can someone suggest an appropriate (safe) capacitor for this purpose, e.g. a Digi-Key or Mouser part number? Should I use one capacitor across the 240VAC or two capacitors, one from each 120VAC line to the common wire? Thanks for the help. _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: AC line bypass capacitors
Digikey carries the Panasonic ECQ-UL series film capacitors that are rated for use as ac line bypass caps. I've used them before in thyristor (triacs, in this case) phase control drivers. They are durable and inexpensive. They are generally either 250vac or 275vac rated. -Bill Sent from my iPhone On Feb 4, 2015, at 12:52 PM, Roger Graves ve...@shaw.ca wrote: My 160 TX is causing RFI to one of my baseboard heater programmable thermostats (switches modes, temperature, when I transmit). The thermostat has a 2 wire connection to 240VAC in a metal receptacle box that has a third wire common ground wire. I would like to try bypassing the AC line. Can someone suggest an appropriate (safe) capacitor for this purpose, e.g. a Digi-Key or Mouser part number? Should I use one capacitor across the 240VAC or two capacitors, one from each 120VAC line to the common wire? Thanks for the help. _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: AC line bypass capacitors
To add to this, I used 1,000vac rated ceramic caps in a VFD once some years back and they failed in spectacular fashion. This was in a 277vac system. Such caps should NOT be used on the AC line! Use the ones intended for AC line filtering. They tend to be film caps and they are intended for this purpose. -Bill Sent from my iPhone On Feb 4, 2015, at 8:01 PM, Jim Brown j...@audiosystemsgroup.com wrote: On Wed,2/4/2015 4:30 PM, Charlie Cunningham wrote: For AC line bypass capacitors look for UL-rated Ceramic Disc capacitors that typically have AC working voltages like 250 VAC or higher. These are designed and rated for AC line service and can take the surges that occur on AC lines. WRONG! As noted in an earlier post, capacitors for use on the AC line must be rated specifically for that use, which includes continuous 120VAC or 240VAC, AND the ability to withstand voltage spikes in the range of 3-6kV. The types are X1 and Y2. See page 21 in k9yc.com/RFI-Ham.pdf 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
