Siemens BG 71 Serie Instrucciones página 5

2 Operation
Before starting any work on the machine, be
sure to isolate it from the power supply.
2.1 Transport, storage
For transport, all lifting eyes should be used for lifting.
For lifting machine sets (such as built-on
gearboxes, fan units), use only the lifting eyes
or lifting pegs provided! Machine sets may not
be lifted by suspending the individual machines! Check the lifting
capacity of the hoist!
If, after delivery, the motors are stored for more than 4 years under
favourable conditions (kept in a dry place free from dust and vibration)
prior to commissioning, the bearings should be regreased. Under
unfavourable conditions, this period is considerably shorter.
If necessary, the insulation resistance of the winding should be checked,
see Section 2.5.
2.2 Installation
After installation, screwed-in lifting eyes should either be removed
or tightened down.
In the case of motors with shaft end facing upwards or downwards (such
as IMV5, IMV6 - see Fig. 1), measures must be taken to ensure that no
water can penetrate into the upper bearing.
The lower part of the terminal box with bushings closes off the pressure-
proof space for the motor housing. The lower part of the terminal box must
not be opened when the motor is connected to the power supply.
The upper part of the terminal box can be turned through 4x90 degrees.
Quiet running
Stable foundations or mounting conditions, exact alignment of the motors
and a well-balanced transmission element are essential for quiet vibration-
free running. If necessary, shims should be inserted under the motor feet
to prevent strain, or the whole rotor and transmission element should be
balanced.
2.3 Balancing, transmission elements
A suitable device should always be used for fitting and removing the
transmission elements (coupling halves, pulleys, pinions) (Fig. 4).
As standard, the rotors are dynamically balanced with the complete
featherkey inserted.
The type of balance is marked on the drive end of the shaft (shaft
end face) or on the rating plate:
(F = balanced with full featherkey)
(H = balanced with half featherkey)
When fitting the transmission element, keep the type of balance in mind!
Balance with half featherkey
Poor running characteristics can arise in the case of transmission
elements having a length ratio of hub length l to length of shaft end l
< 0.8 and running at speeds of > 1500 rev/min (see Fig. 5). If necessary,
re-balancing should be carried out, e.g. the part of the featherkey T
protrudes from the transmission element and above the shaft surface
should be cut back.
The usual measures should be taken to guard
transmission elements from touch. If a motor is
started up without transmission element
attached, the featherkey should be secured to prevent it being
thrown out.
Siemens AG
ENGLISH
2.4 Electrical connection
Check to see that system voltage and frequency agree with the data given
on the rating plate. Voltage deviations of ±5% and/or frequency deviations
of ±2% from the rated values are permitted without the necessity of
derating the output (Area A to DIN VDE0530 Part 1).
Connection and arrangement of the terminal links must agree with the
diagram provided in the terminal box.
Connect the earthing conductor to the terminal with the
Wherever terminal clips are used (for example, to DIN 46282),
arrange the conductors so that the clips are virtually level, i.e. not
tilted when tightened. This method of connection means that the
ends of single conductors must be bent in the shape of a U or be
fitted with a cable lug. This also applies to the green-yellow
protective earthing conductor and the outer earthing conductor
(see Fig. 3.).
Please refer to Fig. 3 for tightening torques for terminal bolts and nuts
(except for terminal strips).
2.5 Checking the insulation resistance
The insulation resistance of the windings must be measured prior to initial
startup of the machine, after long periods of storage or standstill (approx.
6 months).
While the measurement is being taken and immediately afterwards,
some of the terminals carry dangerous voltages and must not be
touched.
Insulation resistance
- The minimum insulation resistance of new, cleaned or repaired
windings with respect to ground is 10 MOhm.
- The critical insulation resistance R
the rated voltage U
(0.5 MOhm/kV):
Measurement
The minimum insulation resistance of the windings to ground is
measured with 500 V DC. The winding temperature should then be 25
± 15 o C.
The critical insulation resistance should be measured with 500 V DC
with the winding at operating temperature.
Checking
If the minimum insulation resistance of a new, cleaned or repaired
machine, which has been stored or been at standstill for a prolonged
period of time, is less than 10 MOhm, this may be due to humidity. The
windings must then be dried.
After long periods of operation, the minimum insulation resistance may
drop to the critical insulation resistance. As long as the measured value
does not fall below the calculated value of the critical insulation
resistance, the machine may continue in operation. If it does, the
machine must be stopped immediately.
The cause must be determined, and the windings or winding sections
repaired, cleaned or dried as necessary.
2.6 Commissioning
M WARNING! Danger of burning!
High surface temperatures of over 80° C can occur
that
p
on the motors. Parts sensitive to heat, e.g. normal
cables or electrical components, must not touch or
be fastened to the motor.
If necessary, take measures to prevent touching!
NOTE: Where the torque is very uneven (the drive of a piston-type
compressor, for example), the inevitable result is a non-sinusoidal motor
current, whose harmonics can lead to excessive system perturbation or
excessive electromagnetic interference.
is calculated first by multiplying
crit
, e.g. 0.69 kV AC, with the constant factor
N
R = 0.69 kV 0.5 MOhm/kV = 0.345 MOhm
*
crit
marking.
o
C
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