Seeking a ~5KV High Current rated contactor/relay
SpaceWyzard, Fri Dec 04 2020, 07:17PMI need a relay that I can use to discharge my HV capacitor bank (about 0.7kJ). I bought one on ebay and it works great, except the contacts keep getting obliterated on the discharge side when the capacitors discharge through them. I bought some silver-coated tungsten contacts that I can solder on, and those also work ok, but I get maybe 30 firings out of them before the tungsten looses from the silver cladding and goes flying off somewhere. I need something that i don't have to keep replacing the contacts on that is made for high voltage, high current discharge that is SPDT and physically about fist sized or maybe a bit larger. I have looked over ebay several times, but can't seem to find exactly what I need. Does anyone have any suggestions for similar projects they have done, or just a link to something like what I am looking for? Thanks!!!
Re: Seeking a ~5KV High Current rated contactor/relay
Nik, Sat Dec 05 2020, 03:57AM
A mercury relay might work for you, I'm not sure if you can get them with high voltage ratings but they wont suffer from exploded contacts as the mercury is self healing.
Nik, Sat Dec 05 2020, 03:57AM
A mercury relay might work for you, I'm not sure if you can get them with high voltage ratings but they wont suffer from exploded contacts as the mercury is self healing.
Re: Seeking a ~5KV High Current rated contactor/relay
MRMILSTAR, Sat Dec 05 2020, 04:25AM
I use a spark gap switch for my pulsed power generator. The triggering is strictly mechanical with one contact being stationary and the other one being spring-loaded. The contacts consist of 2-inch diameter brass round bar. By constructing it carefully I can get the electrodes to come within 0.5 mm of each other. This is good for triggering down to about 2000 volts. The electrodes cannot be allowed to touch because they will weld together. I have used this switch at up to 12,000 joules and 13 KV so far. It has proven to be very reliable and has required no maintenance.
MRMILSTAR, Sat Dec 05 2020, 04:25AM
I use a spark gap switch for my pulsed power generator. The triggering is strictly mechanical with one contact being stationary and the other one being spring-loaded. The contacts consist of 2-inch diameter brass round bar. By constructing it carefully I can get the electrodes to come within 0.5 mm of each other. This is good for triggering down to about 2000 volts. The electrodes cannot be allowed to touch because they will weld together. I have used this switch at up to 12,000 joules and 13 KV so far. It has proven to be very reliable and has required no maintenance.
Re: Seeking a ~5KV High Current rated contactor/relay
SpaceWyzard, Tue Dec 08 2020, 12:40AM
Thank you both. Good suggestions! I like the mercury switch idea a lot of it wasn't for the risk of breakage of the glass. If I could make it robust it sounds cool.
How do you actuate the brass contactor? Manually?
SpaceWyzard, Tue Dec 08 2020, 12:40AM
Thank you both. Good suggestions! I like the mercury switch idea a lot of it wasn't for the risk of breakage of the glass. If I could make it robust it sounds cool.
How do you actuate the brass contactor? Manually?
Re: Seeking a ~5KV High Current rated contactor/relay
MRMILSTAR, Tue Dec 08 2020, 04:21AM
I actuate it manually with a nylon lanyard. I don't trust electronics for triggering these high-energy discharges. For safety I need 100% reliability or as close to that as I can get. I also don't want any conductors, even for triggering, leading back to my hand.
MRMILSTAR, Tue Dec 08 2020, 04:21AM
I actuate it manually with a nylon lanyard. I don't trust electronics for triggering these high-energy discharges. For safety I need 100% reliability or as close to that as I can get. I also don't want any conductors, even for triggering, leading back to my hand.
Re: Seeking a ~5KV High Current rated contactor/relay
SpaceWyzard, Wed Dec 09 2020, 05:14PM
Good call there. Thanks! I will see what I can come up with.
SpaceWyzard, Wed Dec 09 2020, 05:14PM
Good call there. Thanks! I will see what I can come up with.
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