)
Ii
(Min.0
.01
. Others begin the time delay when the relay
is de-energized.
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
1
10
100
1,000
10,000
Ii
= Instantaneous Pickup
-20% +20%
Ii
Ii
(Max.
Time Current Characteristics Curve
Siemens Frame Circuit Breaker
.1
3,000
1,000
100
10
1.37
Synchronous Speed The speed the rotating magnetic field three-phase motor. For example, thermal-
magnetic circuit breaker can tripped either heat or
magnetic force resulting from overcurrent.
.
Thyristor family multi-layer semiconductor devices that includes
silicon controlled rectifiers (SCR), gate turnoff (GTO) thyristors,
and other similar devices.
Time-Current Curve graph showing how long before circuit breaker will trip at
each level fault current.)
Times Continuous Current Rating (In
)
Time
in
seconds
Trip Unit 525
Timing Relay control relay that incorporates preset delay contact
response.
Thermistor device used sense temperature that varies resistance as
temperature changes. Some timing relays begin the time delay when the
relay energized.Thyristors are often used rectifier or
power switching circuits
