What are short time ratings?

A rating defining the load that a machine, apparatus, or device can carry for a specified short time. The size and bulk of metal-frame power breakers at higher interruption and short-time ratings render them impractical.

What does the rating of a generator mean?

The capacity of a synchronous generator is equal to the product of the voltage per phase, the current per phase, and the number of phases. The voltage rating of the generator is normally stated as the operating voltage between two of its three terminals—i.e., the phase-to-phase voltage. …

What do generator kW ratings mean?

To expand on it a bit more, the kW rating is essentially the resulting power output a generator can supply based on the horsepower of an engine. kW is figured by the horsepower rating of the engine times . 746. For example if you have a 500 horsepower engine it has a kW rating of 373.

How do I know my generator rating?

For equipment rated in amperes, you can convert amps to watts with the following formula:

1. For resistive loads (most common type): Wattage = amperes x volts.
2. For reactive loads: Wattage = amperes x volts x load factor.

What is the difference between interrupt ratings and short circuit current ratings?

Specifiers often use the terms short-circuit current rating (SCCR) and interrupting rating (IR) interchangeably. Fuses and circuit breakers must have sufficient IRs for the fault current they interrupt. Usually, the SCCR of a system is much less than the maximum IR of the main overcurrent device.

Why are circuit breakers designed to have a short time rating?

The short-time rating is used by the engineer to determine the ability of the circuit breaker to protect itself and other devices and to coordinate with other circuit breakers so the system will trip selectively.

What is Prime rating of a generator?

The prime power rating is the maximum power accessible at the variable load for an unlimited number of hours per year in a variable load setting. Engines in generator sets may operate up to 750 hours per year at power levels less than the maximum prime power rating.

Is ekW the same as kw?

ekW = electrical power (electrical kW)

What are rated watts?

Running, or rated watts are the continuous watts needed to keep items running. Starting watts are extra watts needed for two to three seconds to start motor-driven products like a refrigerator or circular saw, this is the maximum wattage the generator can produce.

Why are circuit breakers designed to have a short-time rating?