Technical data
ECOFAST Motor Starters
A-4
GWA 4NEB 950 5221-12 DS 02
Switching Frequency
If motors are switched too frequently, the thermal motor model is activated.
The maximum permissible switching frequency depends on the following
operating data:
Fig. A-1: Load diagram for switching frequency
The following diagrams can be used to determine the maximum switching
frequency.
Maximum switching frequency when I
a
= 4 x I
e
(with example)
Fig. A-2: Maximum switching frequency when Ia = 4 x Ie (with example)
I
a
I
e
t
a
t
b
t
ED
t
p
t
s
Load diagram
I
a
Direct motor starting current
I
e
Rated motor operational current
t
a
Motor starting time
t
b
Operating time
t
p
Idle time
t
ED
Cyclic duration factor
t
s
Operating cycle
ED[%] =
t
ED
t
s
x 100%
Thermal
motor model
Class
Example: Cyclic duration factor: 1 s, starting time: t
a
= 0.1 s, I
e
: 6 A, mechanical
switching
Determined switching frequency: approx. 1300 switching cycles/h,
Limit when I
e
= 6 A for mechanical switching
Note: No limit with electronic switching
(dotted line, approx. 3000 switching cycles/h)
Maximum switching frequency when I
a
= 4 x I
e
0.1
1
10
100
1000
10000
Lim
it
a
tion f
o
r
de
vi
ces wi
th
mec
h. switc
hing
elements
Cyclic duration factor t
ED
in [s]
S
w
itc
h
in
g cy
cles/h
Summary of Contents for ecofast 3RK1702-2GB18-0AA1
Page 1: ...Motor Starter Handbuch Manual 04 2009 ecofast Totally Integrated Automation ...
Page 2: ......
Page 12: ...ECOFAST Motorstarter viii GWA 4NEB 950 5221 12 DS 02 ...
Page 40: ...Montage von Motorstartern ECOFAST Motorstarter 3 8 GWA 4NEB 950 5221 12 DS 02 ...
Page 58: ...Gerätefunktionen ECOFAST Motorstarter 6 6 GWA 4NEB 950 5221 12 DS 02 ...
Page 70: ...Bestellnummern ECOFAST Motorstarter C 4 GWA 4NEB 950 5221 12 DS 02 ...
Page 74: ...Korrekturblatt ECOFAST Motorstarter GWA 4NEB 950 5221 12 DS 01 ...
Page 84: ...ECOFAST Motor Starters viii GWA 4NEB 950 5221 12 DS 02 ...
Page 112: ...Installation of Motor Starters ECOFAST Motor Starters 3 8 GWA 4NEB 950 5221 12 DS 02 ...
Page 130: ...Device functions ECOFAST Motor Starters 6 6 GWA 4NEB 950 5221 12 DS 02 ...
Page 138: ...Technical data ECOFAST Motor Starters A 8 GWA 4NEB 950 5221 12 DS 02 ...
Page 146: ...ECOFAST Motor Starters GWA 4NEB 950 5221 12 DS 02 ...
Page 149: ......
