Bill Dube via EV wrote:
We have a huge variac with a bridge diode we call "Mongo charge" that we
use if we let the magic smoke out of all our on-track chargers.
We _never_ leave it unattended. Ever.
If you (or we) decided to leave such a primitive charger
unattended, we would probably use a ~25 Amp, optically isolated, Solid
State relay on the AC side of it. We would run the SS relay from a TTL
line on the BMS. (The SS relays typically have a 3 to 30 VDC optically
isolated control input that will operate nicely from a logic level
output on the BMS.)
Good advice, Bill.
I might add that I don't trust solid-state relays for this purpose --
their failure mode is *ON*! I'd use a real contactor.
It needs to be UL-listed, and rated for at least twice the current you
are switching, and for 120vac (or 240vac); whatever you're switching.
Power for the coil of the contactor must come from the load-side of the
contacts. That way, when it switches off, it removes power from the coil
circuit, so it *stays* off. Then there is no way the contactor can
falsely turn on.
Lee Hart
--
When something bad happens, you have three choices: You can let it
define you; let it destroy you; or you can let it strengthen you.
-- Theodor Seuss Geisel
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
_______________________________________________
UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
ARCHIVE: http://www.evdl.org/archive/index.html
INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org
Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
