Technical data
7
126
Manual – Gear Units and Gearmotors
Additional mass Z, backstop RS and protection canopy C (→ GM)
Project Planning for AC Motors
7.15 Additional mass Z, backstop RS and protection canopy C (→ GM)
Additional
flywheel mass Z
(high inertia fan)
The motor can be equipped with additional mass, the cast iron fan, to achieve smooth
startup and braking behavior of mains operated motors. In this way, the motor obtains
additional mass moment of inertia J
Z
. The cast iron fan replaces a normal fan. The outer
motor dimensions remain the same. It can be installed on motors with and without a
brake. For technical data of the "cast iron fan Z" option, refer to the "Gearmotors" cata-
log.
Backstop RS The mechanical backstop RS is used for protecting equipment against reverse
movement when the motor is switched off. For technical data of the "backstop Z" option,
refer to the "Gearmotors" catalog.
GM
Note the following points:
• Check the starting frequency. Multiply the permitted no-load starting frequency Z
0
with the factor 0.8 or use a forced cooling fan.
• Use the total mass moment of inertia J
ges
= J
mot
+ J
Z
at the motor end. You can find
the values for the mass moments of inertia J
Mot
and J
Z
in the section "Technical data
of additional flywheel mass Z and backstop RS."
• DC injection braking and moving against the RS backstop are not permitted.
• Not available in vibration grade R.
• Only for DT80..: The cast iron fan for DT71.. (part number 182 232 2) is used in com-
bination with a solid shaft encoder or a mounting device for a solid shaft encoder . In
this case J
Z
= 475 • 10
-4
lb-ft
2
must be used for configuration.
GM
03077AXX
Figure 63: Design of the RS backstop
1 Non drive-end bearing shield
2 Wedge element train
3 Driver
123
Specify the direction of rotation for the motor or gearmotor when placing your order. CW
rotation means the output shaft rotates clockwise as viewed onto its face end and is
blocked to prevent it from turning counterclockwise. The vice versa principle applies to
counterclockwise direction of rotation.