Odd voltage level
Odd voltage level
(OP)
If you have a contactor that is rated 18kA on a 1500V system,what is it rated for on a 1000V system?
Is there a rule of thumb? Does the rule work for other components, breakers, etc?
I will check with the manufacturer to make sure, however, for design estimating it would be nice to know.
Regards,
TULUM
Is there a rule of thumb? Does the rule work for other components, breakers, etc?
I will check with the manufacturer to make sure, however, for design estimating it would be nice to know.
Regards,
TULUM






RE: Odd voltage level
RE: Odd voltage level
RE: Odd voltage level
The reason I asked was that on a previous job for a Toshiba vacuum circuit breaker the manual gave the the following formula to evaluate interrupting rating;
New Short Cicuit rating = old SC x (Rate Voltage/actual Voltage).
Just wonder if it applies as a "blanket" rule of thumb.
I will have to check the 18kA rating...
RE: Odd voltage level
RE: Odd voltage level
The actual ANSI/IEEE standard C37.09 was revised in 1999 with fix factor K=Rate Voltage/actual voltage = 1. This means that the standard do not longer support changing the interrupting rating as a function of the voltage at which the vacuum of FS6 interrupting breaker was applied.
NOTE: In the past was common to manufacture oil or air interrupting devices. Today, virtually all MV circuit breakers are either vacuum or SF6 insulated. Those gases are more closely represent a constant current interrupting device, independent of the nominal system voltage.
Since MV vacuum contactor are similar to MV breaker vacuum bottle, will be safe to assume that their interrupting ratings is constant and independently of the operating voltage. .
In short, I will vote to consider the interrupting rating constant independent of the operating voltage.
RE: Odd voltage level
RE: Odd voltage level