Installation and Operational Instructions for BRE250 and BRE400
ROBA-stop
®
-M brake Type 891.
0_ _._
Sizes 250 and 500
(E070 09 203 001 4 EN)
31/10/2019 TK/MW
Chr. Mayr GmbH + Co. KG
Eichenstraße 1, D-87665 Mauerstetten, Germany
Phone: +49 8341 804-0, Fax: +49 8341 804-421
Page 14 of 20
your reliable partner
Electrical Connection and Wiring
DC current is necessary for operation of the brake. The coil nom-
inal voltage is indicated on the Type tag as well as on the brake
body and is designed according to the DIN IEC 60038 (± 10 %
tolerance). Operation can take place with alternating voltage us-
ing a rectifier or another suitable DC power supply. The connec-
tion possibilities can vary dependent on the brake equipment.
Please follow the exact connections according to the Wiring Dia-
gram. The manufacturer and the user must observe the applica-
ble regulations and standards (e.g. DIN EN 60204-1 and DIN
VDE 0580). Their observance must be guaranteed and double-
checked!
Grounding Connection
The brake is designed for Protection Class I. This protection co-
vers therefore not only the basic insulation, but also the connec-
tion of all conductive parts to the protective conductor (PE) on
the fixed installation. If the basic insulation fails, no contact volt-
age will remain. Please carry out a standardised inspection of
the protective conductor connections to all contactable metal
parts!
Device Fuses
To protect against damage from short circuits, please add suita-
ble device fuses to the mains cable.
Switching Behaviour
The reliable operational behaviour of a brake is to a large extent
dependent on the switching mode used. Furthermore, the switch-
ing times are influenced by the temperature and the air gap be-
tween the armature disk and the coil carrier (dependent on the
wear condition of the linings).
Influencing the switching time
The same switching time can be used for rectifiers manufactured
by Getriebebau Nord and for those manufactured by
mayr
®
(see
Table
2 and section “Protection circuit”).
Magnetic Field Build-up
When the voltage is switched on, a magnetic field is built up in
the brake coil, which attracts the armature disk to the coil carrier
and releases the brake.
Field build-up with normal excitation
If the magnetic coil is energised with nominal voltage, the coil
current does not immediately reach its nominal value. The coil in-
ductivity causes the current to increase slowly as an exponential
function. Accordingly, the build-up of the magnetic field takes
place more slowly and the braking torque drop (curve 1) is also
delayed.
Field build-up with overexcitation
A quicker drop in braking torque is achieved if the coil is tempo-
rarily placed under a higher voltage than the nominal voltage, as
the current then increases more quickly. Once the brake is re-
leased, it needs to be switched over to the nominal voltage
(curve 2). The ROBA
®
-(multi)switch fast acting rectifier and
phase demodulator work on this principle.
Current path
Braking torque path
Magnetic Field Removal
AC-side switching
The power circuit is inter-
rupted in front of the rectifier.
The magnetic field slowly re-
duces. 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 (approx. 6-10 times longer than
with DC-side disconnection), use for non-critical braking times.
DC-side switching
The power circuit is inter-
rupted between the rectifier
and the coil as well as mains-
side. The magnetic field re-
duces extremely quickly. This
causes a quick rise in braking
torque.
When switching DC-side, high
voltage peaks are produced in
the coil, which can lead to
wear on the switching con-
tacts from sparks and to de-
struction of the insulation.
DC-side switching means
short brake engagement times (e.g.
for EMERGENCY STOP operation)
; however, louder switching
noises.
Protection circuit
When using DC-side switching, the coil must be protected by a
suitable protection circuit according to VDE 0580, which is inte-
grated in
mayr
®
-rectifiers. To protect the switching contact from
consumption when using DC-side switching, additional protective
measures are 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 volt-
age and the rated operating current are sufficient.
Depending on the application, the switching contact can also be
protected by other protection circuits (e.g.
mayr
®
-spark quench-
ing unit, half-wave and bridge rectifiers), although this may of
course then alter the switching times.
Coil
F1: external fuse
Coil
F1: external fuse
