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