Installation and Operational Instructions for ROBA
®
-diskstop
®
Type 894.5_ _._ _ Sizes 9 and 10
(B.8.4.5.EN)
27/08/2020 TK/TL/GC/SU
Chr. Mayr GmbH + Co. KG
Eichenstraße 1, D-87665 Mauerstetten, Germany
Phone: +49 8341 804-0, Fax: +49 8341 804-421
Page 14 of 17
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Electrical Connection and Wiring
The brakes must only be operated with
overexcitation.
DC current is necessary for operation of the brake. The coil
nominal 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). The brake must only be operated with
overexcitation (e.g. using a ROBA
®
-switch or -multiswitch fast
acting rectifier or phase demodulator). The connection
possibilities can vary dependent on the brake equipment. Please
follow the exact connections according to the Wiring Diagram.
The manufacturer and the user must observe the applicable
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
covers therefore not only the basic insulation, but also the
connection of all conductive parts to the protective conductor
(PE) on the fixed installation. If the basic insulation fails, no
contact voltage 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
suitable 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
switching times are influenced by the temperature and the air
gap between the armature disk and the coil carrier (dependent
on the wear condition of the linings).
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
inductivity 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
temporarily placed under a higher voltage than the nominal
voltage, as the current then increases more quickly. Once the
brake is released, 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
interrupted in front of 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 (approx. 6-10 times longer than
with DC-side disconnection), 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 reduces 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 contacts from
sparks and to destruction 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
integrated 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 voltage 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
quenching unit, half-wave and bridge rectifiers), although this
may of course then alter the switching times.
Coil
F1: external fuse
Coil
F1: external fuse
