S1
F1
L
N
1
2
3
4
5
6
7
8
1 2 3 4 5 6 7 8
20/017.000.2
200 - 500V~
200 - 300V~
R: 0
Ω
-10M
Ω
IN
OUT
U– = 0,45×U~
+
–
S
DC
ROBA -switch
I
= 1,8A
max
–
0,05-2sec
t:
R
R
S1
F1
L
N
1
2
3
4
5
6
7
8
1 2 3 4 5 6 7 8
20/017.000.2
200 - 500V~
200 - 300V~
R: 0
Ω
-10M
Ω
IN
OUT
U– = 0,45×U~
+
–
S
DC
ROBA -switch
I
= 1,8A
max
–
0,05-2sec
t:
R
R
0
0 %
20 %
40 %
60 %
80 %
100 % 120 % 140 % 160 %
140 %
120 %
100 %
80 %
60 %
40 %
20 %
0 %
34 %
50 %
125 %
160 %
Electrical Connection
Holding brake
equals
15 %
spring force
for Sizes 2 – 500
Coil
F1: external fuse
Coil
F1: external fuse
** RMS coil capacity P
RMS
P
RMS
≤
P
nom
The coil capacity P
RMS
must not be larger than P
nom
.
Otherwise, the coil may fail due to thermic overload.
Calculations:
P
RMS
[W]
RMS coil capacity, dependent on switching
frequency, overexcitation, power reduction and
switch-on time duration
P
RMS
=
P
over
x t
over
+ P
hold
x t
hold
t
tot
P
nom
[W]
Coil
nominal
capacity
(Catalogue
values
or
Type tag)
P
over
[W]
Coil capacity on overexcitation
P
over
=
(
U
over
)²
x P
nom
U
nom
P
hold
[W]
Coil capacity on power reduction
P
hold
=
(
U
hold
)²
x P
nom
U
nom
t
over
[s]
Overexcitation time
t
hold
[s]
Time of operation with power reduction
t
off
[s]
Time without voltage
t
tot
[s]
Total time (t
over
+ t
hold
+ t
off
)
U
over
[V]
Overexcitation voltage (bridge voltage)
U
hold
[V]
Holding voltage (half-wave voltage)
U
nom
[V]
Coil nominal voltage
Time Diagram:
U
over
U
nom
U
hold
t
tot
t
on
t
off
t
over
t
hold
*
Overexcitation time t
over
Increased wear and therefore an enlarged air gap as well as coil
heat lengthen the separation time t
2
of the brake. Therefore, as
overexcitation time t
over
, please select at least double the separation
time t
2
with nominal power on each brake size.
The spring forces also influence the brake separation time t
2
: Higher
spring forces increase the separation time t
2
and lower spring forces
reduce the separation time t
2
. The separation time t
2
alterations due
to the spring configuration can be seen in the adjoining diagram.
Spring force (braking torque adjustment) < 100 %:
The overexcitation time t
over
is less than double the separation time
t
2
on each brake size.
Example: braking torque adjustment = 34 %
--> separation time t
2
= 50 %
--> overexcitation time t
over
= 200 % x 50 % = 100 % t
2
Spring force (braking torque adjustment) = 100 %:
The overexcitation time t
over
is double the separation time t
2
on each
brake size.
Spring force (braking torque adjustment) > 100 %:
The overexcitation time t
over
is higher than double the separation
time t
2
on each brake size.
Example: braking torque adjustment = 125 %
-->
separation time t
2
=
120
%
--> overexcitation time t
over
= 200 % x 120 % = 240 % t
2
•
•
•
Magnetic Field Removal
AC-side switching
The power circuit is interrupted
before the rectifier. The magnetic
field slowly reduces. This delays
the rise in braking torque.
When switching times are not
important, please switch AC-side,
as no protective measures are
necessary for coil and switching
contacts.
AC-side switching means
low-noise switching
; however, the brake
engagement time is longer (c. 6 – 10 times longer than with DC-side
switch-off). Use for non-critical braking times.
DC-side switching
The power circuit is interrupted
between the rectifier and the coil as
well as mains-side. The magnetic
field is removed very quickly,
resulting in a rapid rise in braking
torque.
When switching DC-side, high
voltage peaks are produced in
the coil, which lead to wear on
the contacts from sparks and to
destruction of the insulation.
DC-side switching means
short brake engagement times (e.g. for
EMERGENCY STOP operation)
. However, this produces louder
switching noises.
Protective Circuit
When using DC-side switching, the coil must be protected by
a suitable protective circuit according to VDE 0580, which is
integrated in
mayr
®
rectifiers. To protect the switching contact from
consumption when using DC-side switching, additional protective
measures may be necessary (e.g. series connection of switching
contacts). The switching contacts used should have a minimum
contact opening of 3 mm and should be suitable for inductive load
switching. Please make sure on selection that the rated voltage
and the rated operation current are sufficient. Depending on the
application, the switching contact can also be protected by other
protective circuits (e.g.
mayr
®
spark quenching units), although this
may of course then alter the switching times.
•
•
•
Holding brake
equals
160 %
spring force
for Size 1000
Diagram:
Brake separation time t
2
dependent on spring configuration
Spring force (braking torque adjustment in %)
Separation time t
(in %)
1
1
