rfranzk

Hello all, What about using a non contact tachometer that uses a refelective tape applied to the rotating surface? This would eliminate or reduce any balance problems using magnets and weights. Take a look at the link for one. rfranzk. http://www.amazon.com/Neiko-Professional-Digital-Non-Contact-Tachometer/dp/B000I5LDVC

Hello and Thanks!!! Thanks HTG for the schematic and eagle files. Just had a chance to look at them this p.m. A couple of questions. On the resistors you don't have specified wattage. I am assuming 1/4 watt is good for this?? On the caps, just a ceramic?? or is tantalum or some other type a better choice?? And last the schematic notes say to increase value of R4 to increase voltage. I assume this is the voltage of the trigger output signal?? And one more, would not adjustment of P1 change this setting also?? I attempted to wrap 5 to 6 loops around fence and did not measure any voltage with a cheapo multimeter. Will try it again with my good meter. I see the design is scaled for .1mv input and my cheapo meter may not be sensitive enough to read this. My plan is to breadboard this first and try it before I etch a board. I will keep you posted on results. Will probably be a couple of weeks. Many Thanks again and again. rfranzk.

Thanks for your input HERO999, I was curious about the low current as well. With capacitive coupling would you still recommend the 50v/2ma neon bulb?? All I want is a visual of fence operation from a distance of 1/4 to 1/2 mile. I would like to have a high and low voltage indicator to inform me of potential load on fence from weeds etc. Would be nice if it was visible in daylight but not absolutely necessary. I would consider building a battery powered led system if the current transformer signal could be amplified to switch a semiconductor and if power consumption could be kept low. (Could use nicad or nimh pack and solar charger also) With the capacitive coupling arrangement, is gauge of wire important or just connected? I have anything from 24 gauge to 2 gauge cable available. With the transformer arrangement would fewer turns and a heavier cable provide more current, low enough voltage to drive led?? I also have 16 gauge high voltage wire that I think is rated for 10 kv. I will have to look. Lots to think about and experiment with, Will be a week or so before I have time to do so. Could use one of these led type lenses with different color leds for voltages. http://www.goldmine-elec-products.com/prodinfo.asp?number=G16752 Thank You so much for your response. rfranzk

Thanks for the quick reply HTG, Great idea of winding a few turns around the fence a sort of current transformer. Any recommendations on gauge of wire?? What about having multiple lights for multiple voltage outputs?? Would this be accomplished with multiple xformers, or one with multiple taps? It may be possible to drive led arrays with reflectors. I will experiment with this idea. Thanks again, rfranzk.

Hello all, I want to build a two or three light display that is driven by the fence charger and can be seen from 1/4 to 1/2 mile away. I was thinking of using a voltage divider network and either xenon or neon tubes with reflectors and lenses. The bulbs I am considering are neon standard brightness (http://www.chml.com/products/pdf/5-4.pdf) that draw .3 ma current and breakdown at 115vdc. I would like to have an indicator of 2kv, (red lens) 4kv (Yellow lens) and 6kv (green lens) highest kv flashing all 3 lamps. The questions I have are related to current draw and load on the fence and also since the input voltage is what varies, how to calculate the divider circuit. The input could be has high as 10 kv but more likely in the 7.5 to 8 kv range. I assume the divider should supply approximately 115 volts at each resistor to light the lamp. If I calculate for an 8 kv input will the voltage increase be too much at the display with a 10 kv input causing bulb failure? Will a partially shorted fence, ie weeds touching fence cause the voltage to drop below levels of flashing the 2kv lamp? The voltage is not applied constantly but in 50 ms pulses at intervals of 500 ms to 1000 ms. I know the bulb current draw can load the fence and cause reduced effectiveness. If two lights are better for efficient fencer output I can live with that. Or circuit that would only flash one light depending on input. Any recommendations would be greatly appreciated. Thanks in advance. rfranzk.

Thanks for your reply. I guess I will either have to pony up and purchase one or put another project on the burner. I appreciate the input. I would be interested in schematics for a dc clamp on meter. Thanks. rfranzk

Hello Everyone. I have a fairly inexpensive clamp on multimeter with ac current capabilities 20 amps to 400 amps. I work more with dc and am curious if a modification could be made to read dc current with some accuracy. I sometimes measure currents at 300 to 400 amps dc with voltages between 12 and 48 volts. (Automotive and electric golf carts) I have a dc current probe that interfaces with my dmm that is limited to 30 amps for smaller measurements. Thanks in advance for any ideas and feed back. rfranzk.

Hello folks: I made a spot welder based on this one using 2 farad capacitor for stereo system woofer a power supply, large triac and some cables. check it out. rfranzk. http://www.philpem.me.uk/welder/

Hi Ante!! Yes it is a polymer positive temperature coefficient switch!! I am curious about using them to protect the batteries of a cordless tool during the charge process. Most battery packs use a thermal circuit breaker that measures battery temperature and cuts off charge current. http://www.pepiusa.com/ The pptc will change resistance at temperature. I am unsure as to whether these can be surface mounted to battery to sense battery temperature or whether they change temperature and resistance based on current flow or resistance to flow? Also what do I consider when choosing the proper device? Thanks for the quick reply rfranzk

Hi Ante!!! I have welded a few battery packs with my capacitive discharge welder and am looking for a source for the pepi thermal fuses, or information on how to configure pptc device to battery pack. The pptc resistance changes with temperature and I am unsure how temperature rises during the charge cycle will affect overall operation. I have looked hi and lo for sources and have had no luck on the pepi. Thanks in Advance. rfranzk

Hi auidoguru. Thanks for the quick reply. I knew this was the case with analog vein type meters but was unsure about the digital displays. I will dig up schematics and possible photos of completed stuff. ps. I made the supply to power a capacitive discharge welder for welding battery packs. works cool!! Thanks rfranzk

Hello everyone. I would like to have a digital ammeter to add to my recently completed 0-30 volt power supply. Is supposed to have a 30 amp capacity. Have not tested it that hard at this point. Can this meter be easily modified to read current??? Thanks in advance for any help rfranzk

Hi Ante!! I have been distracted lately. Moved and some other stuff and still don't have internet service at my home. I did complete a capacitive discharge welder with an adjustable power supply (just completed) a 2 farad audio capacitor and large triac to trigger the discharge. Works well for my intended purpose. I am also experimenting with another transformer recently aquired at a farm auction. Will send photos of project and weld results when possible. Thanks for your help rfranzk

Hi Ante, I have not measured voltage drops. Good idea !! I have tried brass, aluminum and copper contacts. I have tried different tip and contact areas and shapes. I have some tungsten contacts I can try. Havn't yet. I will have to dig up a digital camera to send photos. I do not know what you mean about the solid state relay zero crossfire?? The one shot timer and relay circuit are isolated and powered with 12v dc from a battery pack. I will check voltage drops and get back. I suspect this is an issue but also feel that contact pressure could be a problem with this arrangement. Thanks rfranzk.

Hi Ante,