Thanks VTer - That was my original intent, but the responses I received sent me down the road of removing all gf protection. I like the idea of having fast acting low magnitude fault protection. I guess I would just need to set pickup above the charging current value (1a/MVA) to avoid...
Appreciate it, Groovy. Unfortunately this is an existing installation. So rather than try to use the ZSCT for high impedance faults (below contactor rating), I should short/ground the zsct and rely on the fuse for any/all ground faults, correct?
I'm hoping someone can provide some insight into ground fault pickup settings.
Motor info:
1. 2400 volt;
2. Solidly grounded;
3. Fuse/vacuum contactor starter;
4. 1.15 SF
5. ~8k amps ground fault current
6. Zero sequence 50:5 CT for ground fault protection;
7. 300Hp
I've read through the Buff...
@waross - Great response, that makes sense. So without knowing all of those operating characteristics and not wanting to risk motor damage, it sounds like setting just below the hot stall curve would be the most conservative approach. I've also read some papers which indicate to set the the...
Saw this post and was wondering the same thing. Has this been asked/answered anywhere else? rockman7892's post was never answered.
"rockman7892 (Electrical)
(OP)
16 Jan 10 11:42
I have recently been looking at some motor protection relay curves and noticed some curves that were set below both...
