SIEMENS
6/30
Siemens MD 50.8 · 2017
Motor options
Mounted components
Brake
6
■
Brake options
(continued)
Monitoring
Brake with microswitch to monitor the release
The air gap
s
gap
of the brake is monitored by a microswitch
mounted on the base plate of the solenoid assembly.
The motor does not start up until the brake has been fully released
(
s
gap
= 0) and the armature disk is in contact with the solenoid
assembly. The microswitch is actuated and controls the motor
contactor.
When the brake is switched off, the armature disk reaches the
maximum air gap (
s
gapmax
) and the microswitch opens. This
means that the motor contactor is not controlled and the motor
does not start.
This method is used for machines and units which require a pre-
cisely defined starting and braking procedure, as well as for fault
monitoring of faulty rectifiers, interrupted connecting cables,
faulty solenoids, and excessively large air gaps (brake solenoid
cannot fully attract the armature disk).
The microswitch for air gap monitoring is available for brakes in
sizes L32 to L150.
Note:
The mechanical components of the microswitch must be
protected against icing at low temperatures.
Fig. 6/43
Circuit principle with microswitch
Brake cable protection
The brake cable of the geared motors is normally routed through
the cable gland of the terminal box.
We are offering an optional version of brake cable routing which
ensures enhanced protection for the brake cable. In this version,
the brake cable is brought into the motor directly under the fan
cover through a hole in the base of the terminal box. This
arrangement ensures that most of the cable is covered and
protected against mechanical damage.
Enclosed brake
The brakes L can be supplied as enclosed brakes.
Enclosed brakes include a dust protection ring around the
circumference and an integrated shaft sealing ring at the shaft
outlet. This prevents the release and penetration of dust,
moisture, and other pollution. Other advantages are reduced
noise when applying the brake as well as, in combination with a
motor anti-condensation heater, a reduced risk of the rotor
freezing on the friction surfaces.
In addition, a condensation drain hole can be incorporated in the
dust protection ring for brakes L.
The enclosed brake can also be shipped in combination with a
manual brake release lever and a manual brake release lever
with locking mechanism.
Corrosion protection
The brakes L are supplied as standard with corrosion protection.
A friction plate or adapter flange is always mounted between the
mating friction surface (end shield on the ventilation side) and
the rotor. The rotor is made of a rustproof material.
Brake with increased corrosion protection
The adapter flanges and armature disks of the brakes are
chromium-plated for increased protection against corrosion.
This prevents the friction surfaces from seizing up.
Increased corrosion protection is employed when a motor is
used in corrosive environmental conditions (high air humidity,
dripping water, crane systems, for example) and/or during
prolonged standstill periods.
Order code:
Microswitch for monitoring brake release
C04
Order code:
Brake cable protection
C80
G_D087_XX_00033
–
L1
N
L2
L3
Order code:
Enclosed brake
C01
Enclosed brake
with condensation drain hole
C11
Order code:
Increased corrosion protection
C10
Corrosion protection
Brake type
Design
Material
L4
L8
L16
L32
L60
L80
L150
Standard corrosion protection
Friction
surface
to the motor
Friction plate of
stainless steel
✓
✓
✓
✓
✓
✓
Adapter flange
with thin zinc film
✓
Armature disk
Gas-nitrided
✓
✓
✓
✓
Thin zinc film
✓
✓
✓
Increased corrosion protection
Friction
surface
to the motor
Friction plate of
stainless steel
✓
✓
✓
✓
✓
✓
Chromium-plated
adapter flange
✓
Armature disk
Chromium-plated
✓
✓
✓
✓
✓
✓
✓
© Siemens AG 2017