Technical data

DANGER
Bodily harm by hazardous movements due to falling or sinking axes!
Secure vertical axes against falling or sinking after disconnection:
● lock the vertical axes mechanically,
● provide an external braking / collecting / clamping device, or
● ensuring sufficient equilibration of the vertical axes.
⇒ The serially delivered, from the control device driven holding brakes them-
selfs, are not suited for personal safety!
Ensure protection of persons by superordinate fail-safe measures.
Cordon off the hazardous area by means of a safety fence or a safety screen.
Observe supplementary DIN and recommendations.
For European countries:
● DIN EN 954 / 03.97 on security-related parts of controllers.
● Leaflet Vertical axes (Editor: Süddeutsche Metall - Berufsge-
nossenschaft Fachausschuss Eisen und Metall II, Wilhelm–
Theodor–Römheld-Str.15, 55130 Mainz, Germany)
For US:
● See National Electric Code (NEC), National Electrical Manu-
facturers Association (NEMA) as well as local building regu-
lations.
The following is generally valid: the national terms must be ob-
served!
9.9.2 Dimension of Holding Brakes
General
Holding brakes on motors of Rexroth are basically not designed for service
braking. The effective braking torques are physically conditionally different in
static and dynamic operation.
Normal Operation Fault Condition (EMERGENCY STOP)
In normal operation, using the holding
brake for clamping of an axis standstill, the
brake`s static torque (M4) rating in the da-
ta sheets applies directly as static friction
(M4) – stiction (friction coefficient μ
H
).
In fault conditions (i.e., EMERGENCY
STOP), where the holding brake is used to
stop a moving axis, the ”dynamic braking
torque”, or sliding friction (friction factor
μ
G
) applies.
M4 > M
dyn
Therefore, note the following description of dynamic dimensioning.
Fig.9-20: Dynamic sizing
The load torque must be smaller than the minimum dynamic torque M
dyn
which
the holding brake can provide. Otherwise the dynamic holding brake torque is
not sufficient to stop the axes.
If a mass is to be decelerated in a defined time or in a defined route, the addi-
tional mass moment of inertia of the whole system must be taken into account.
To ensure construction safety, reduce the required holding torque to 60% of
the static holding torque (M4) of the holding brake.
Dynamic sizing
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Rexroth IndraDyn S | Project Planning Manual
Operating Conditions and Application Notes