Lenze MDSLS Servo spindle motor - Manual (Page 18)

Technical data
Rated data
Spring-operated brakes
3

18 BA 33.0003 EN 1.0
3.3.1 Spring-operated brakes
The spring-operated brakes can be used as holding and/or servicebrakes. Ifused as service
brake, the permissible friction energy must not be exceeded; otherwise it would destroy
the brake. Permissible operating speeds and ratings E Spring-operated brakes catalogue.
Emergency stops from a higher speed are possible, but wear increases with high switching
energy.

Stop!
In any case, the friction surfaces must be kept free of lubricant and grease,
since even small amounts can drastically reduce the braking torque.
The use as a pure holding brake results in only minor wear at the friction surfaces.
Emergency stops or the use as service brake creates wear at the friction surfaces, and the
abrasion of the wear parts creates dust. The Lenze spring-operated brake BFK 458 can be
adjusted up to 5 times, while the BFK 418, 457 and 460 cannot be adjusted (for details E
catalogues and operating instructions ofspring-operated brakes).Brakes,whichcannotbe
adjusted, must be replaced after reaching the wear limit.
The friction energy per switching cycle is calculated as:
Q ½ J ∆ 2
M
K
Q [J] Friction energy
Q = ½ ⋅ J
total
⋅ ∆ω 2 ⋅
M
K
M
K
− M
L
J
total
[kgm 2 ] Total mass moment of inertia (motor + load) M
K
M
L
∆ω Angular speed ω=2π n /
60
, n= speed [min -1 ]
M
K
[Nm] Characteristic torque
M
L
[Nm] Load torque
and must not exceed the limit value, which is dependent on the operating frequency, for
braking during operation and also for emergency stops (E Spring-operated brake
catalogue).
Depending on the operating conditions and possible heat removal, the surface
temperatures can reach up to 130 °C.
The spring-operated brakes operate according to the closed-circuit principle, i.e. the brake
is closed in the de-energized state. The brakes can be fed with a bridged DC voltage(bridge
rectifier) and a smooth DC voltage. The permissible voltage tolerance is ±10%.
Note!
For additional information see the catalogues and operating instructions of
spring-operated brakes.
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