HV Capacitor for fence ctrl.
HV Capacitor for fence ctrl.
(OP)
Hi all,
I'm designing an electric fence controller, and currently working on the HV stage. I'm leaning for a standard appproach with a switch-mode charger for a big HV cap, and a SCR to dump the cap charge in the HV transformer, connected to the fence.
I'm looking for a 1200Vdc, 20uF cap for the HV pulse generator, but those are difficult to find. I appreciate any cap supplier contact info for this application. Any ideas or hints from more experienced designers are welcome, as well.
I'm designing an electric fence controller, and currently working on the HV stage. I'm leaning for a standard appproach with a switch-mode charger for a big HV cap, and a SCR to dump the cap charge in the HV transformer, connected to the fence.
I'm looking for a 1200Vdc, 20uF cap for the HV pulse generator, but those are difficult to find. I appreciate any cap supplier contact info for this application. Any ideas or hints from more experienced designers are welcome, as well.





RE: HV Capacitor for fence ctrl.
Z
RE: HV Capacitor for fence ctrl.
RE: HV Capacitor for fence ctrl.
Have you considered a power factor correction capacitor? Not sure on the continuous DC rating but likely to be 1200V or higher for service on a 400V system. They won't be as good as the polypropylene types in terms of pulse performance but for an electric fence is it that critical?
You are storing a large amount of energy - follow hacksaw's advice and check the permissible limits.
----------------------------------
If we learn from our mistakes I'm getting a great education!
RE: HV Capacitor for fence ctrl.
RE: HV Capacitor for fence ctrl.
We need 6-13KV for a 4000mts cable length. The pulse must be short enough not to harm animals/people or burning dry grass. Not sure, but any pulse <1ms or 2-3J energy would be OK with our local regulations.
A starting point may be a very simple switching inverter, to charge the cap through a diode bridge. A cheap SCR would discharge it through a HV transformer primary, with the 2ary connected to the fence.
A microcontroller would drive the inverter PWM and provide voltage control and misc. funcions (alarms, line/Earth monitor, etc.)
As said, I'm new to this so any hints, better ideas or sample circuits are highly appreciated.
Thanks.
RE: HV Capacitor for fence ctrl.
RE: HV Capacitor for fence ctrl.
Keith Cress
kcress - http://www.flaminsystems.com
RE: HV Capacitor for fence ctrl.
Is correct to say lower voltage means higher capacitance, to keep the same pulse energy (roughly 1/2CV^2)?
Thanks.
RE: HV Capacitor for fence ctrl.
Alan
----
"It's always fun to do the impossible." - Walt Disney
RE: HV Capacitor for fence ctrl.
Keith Cress
kcress - http://www.flaminsystems.com
RE: HV Capacitor for fence ctrl.
Some of our customers would like to check if the gardener cut the lines, without harming him. Is there any way to check for line continuity while the fence is not armed?
something like power line carrier?
BTW, we don't want to decorate our fences with fried people or cattle, just some warning pulses and then switch to an audible alarm if earth got shunted or lines were cut.
Thanks to all.
RE: HV Capacitor for fence ctrl.
http://www.patriotchargers.com/
http://ww
http://w
http://www.taylorfence.net/
Keith Cress
kcress - http://www.flaminsystems.com
RE: HV Capacitor for fence ctrl.
RE: HV Capacitor for fence ctrl.
Operahouse: Local regulations here allow us using some 7KV, 2J pulses shorter than 1ms and up to 1Hz rate, measured on a 500 ohm load (rough impedance model for a child or dog, I guess).
We got this sample fence energizer with alarm features, locally available and approved:
www.powerfence.com/default.aspx?pageid=459
The label says 6KV/2.9J pulses, 715us wide, each 1.4s. Looks like a good starting point.
-----------
Do you know any transformer supplier for this kind of energizers?
Thanks for your help!