0
.37
Synchronous Speed The speed the rotating magnetic field three-phase motor.
Time Current Characteristics Curve
Siemens Frame Circuit Breaker
.
Thyristor family multi-layer semiconductor devices that includes
silicon controlled rectifiers (SCR), gate turnoff (GTO) thyristors,
and other similar devices. For example, thermal-
magnetic circuit breaker can tripped either heat or
magnetic force resulting from overcurrent.01
.1
1
10
100
1,000
10,000
Ii
= Instantaneous Pickup
-20% +20%
Ii
Ii
(Max.
Thermistor device used sense temperature that varies resistance as
temperature changes.)
Times Continuous Current Rating (In
)
Time
in
seconds
Trip Unit 525
Timing Relay control relay that incorporates preset delay contact
response. Others begin the time delay when the relay
is de-energized.
.
Time-Current Curve graph showing how long before circuit breaker will trip at
each level fault current.1
3,000
1,000
100
10
1. Some timing relays begin the time delay when the
relay energized.)
Ii
(Min.
Synchronous Speed (Ns) =
f frequency
P number poles
120f
P
Thermal-Magnetic Used describe device that uses both heat and magnetism
as part its operating principles.
Synchronous speed determined the line frequency and the
number motor poles.Thyristors are often used rectifier or
power switching circuits
