SIEMENS
7/11
Siemens CR 1 · 2015
7
■
Technical specifications
(continued)
SIMOTICS motors for cranes
General technical specifications
Bearings
All motors are equipped with rolling-contact bearings.
Motors equipped with cylindrical roller bearings are shipped
with a rotor shipping brace to prevent brinelling in the DE
1)
bearings during transportation and storage.
Shaft extensions
The squirrel-cage motors up to and including shaft height 160
have cylindrical shaft extensions. The motors are always sup-
plied with a featherkey inserted in the shaft.
Coupling
The standard versions of hoisting gear motors are designed for
coupling output. Pinion, chain, and belt outputs generate greater
cantilever forces and bearing loads, which must be taken into
account.
Motor protection
Hoisting gear motors are operated with a higher load factor in in-
termittent duty. If there is excessive power consumption, an un-
dervoltage in the supply, an excessive ON duration, or excessive
coolant temperatures or if the heat is not being dissipated ade-
quately (speed of naturally cooled machines is too low), this can
cause the temperature in the windings to rise and the motors to
overheat. Direct and indirect measures can be taken to protect
the motors from overheating. An adequate monitoring concept
should take into account all the relevant factors.
In intermittent duty, devices that offer indirect protection (e.g.
circuit-breakers, overload relays, or
I
2
-t
monitors) can only
partly detect the causes of overheating.
The most reliable method is to detect excessively high tempera-
tures directly at the point at which they occur (i.e. the machine
windings). In this way, the effects of all possible causes can be
detected by a single means.
The resistance of the PTC thermistor detectors integrated in the
windings increases significantly if the response temperature is
exceeded. A tripping unit (Catalog LV1) detects this increase
and uses a contact to intervene in the open-loop control. An ad-
ditional detector loop for emitting a warning signal just below the
shutdown temperature can also be used in process-critical pro-
duction processes to allow working cycles that have already
been started to be brought to an end.
It is recommended that KTY 84 temperature sensors be installed
in converter-fed drives (the basic version of 1PH8 motors are
equipped with these sensors as standard). This sensor is em-
bedded in the winding head of the motor in the same manner as
a PTC thermistor. The data is evaluated directly in the converter.
Warning and shutdown response limits can be set. Since only
one sensor can be evaluated in the converter, this motor protec-
tion method is only suitable in single-motor drives; PTC thermis-
tors are recommended for drives with more than one motor (e.g
crane traversing gears).
1)
DE is the motor's drive end with shaft. NDE is the motor's non-drive end.
© Siemens AG 2015