Siemens LOHER CHEMSTAR 1PS2, Operating Instructions And Installation

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4.10 Voltage and frequency fluctuations during line operation
The ranges stated on the rating plate and in the documentation (e.g. range B acc. to
IEC / EN 60034 1) for voltage fluctuation (± 10%) and frequency fluctuation (± 2 %) must be
maintained at all times.
The following always applies: Under practical operating conditions, a machine may sometimes
have to be operated outside the tolerance limits. Exceptions of this sort should be limited with
regard to the values that arise, how often and for how long they occur. Where possible and
within a reasonable time take corrective actions such as reducing the power. Such actions can
avoid thermal ageing leading to a reduction in the service life of the machine.
NOTICE
Overheating of the winding
Exceeding the permissible tolerances for voltage and frequency can lead to an impermissibly
high temperature rise in the windings and thus cause long-term damage to the machine.
Every machine must be protected against an inadmissible temperature rise. Observe the
following notes:
● Protect every machine according to IEC/EN 60079–14 using a current-dependent, delayed
circuit breaker with phase failure protection according to IEC/EN 60947 or a similar device
in all phases.
● Set the protective device to the rated current (value is stamped on the rating plate).
● Select the protective device so that the machine is thermally protected even with a locked
rotor.
● For explosion-protected electrical machines with type of protection "Increased safety", also
monitor the starting (starting monitoring with EC or EU type-examination certificate
according to Directive 2014/34/EU or IECEx scheme with Certificate of Conformity). When
the rotor is locked, the protective device must trip within the tE time (safe locked rotor time).
This requirement is satisfied if the tripping time is not longer than the specified tE time.
● Protect the windings in a delta connection in such a way that the tripping unit or relay is
connected in series with the winding phases. When selecting and setting the tripping unit,
define the rated value of the phase current. The phase current is 0.58 times the rated
machine current. Any thermal machine protection via direct temperature monitoring to be
used in addition to the machine circuit breaker is specified on the rating plate if required.
Preparations for use
4.10 Voltage and frequency fluctuations during line operation
LOHER CHEMSTAR 1PS2
Operating Instructions 08/2016
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