Performance: Must act according
to the technological requirement choice performance appropriate
frequency changer, do not have one-sidedly to pursue the high
performance, because a performance higher price is also higher.
The air blower water pump uses the frequency changer, the
ordinary sine pulse-duration modulation frequency changer then answers
the purpose, because the air blower water pump is the square torque
loading, when low speed the torque obviously drops, moreover the air
blower water pump does not need the high accuracy rotational speed and
the complex control function (for example is reversing and so on).
If controls the compressor, because compressor torque
characteristics quite complex, in particular starting moment very big,
therefore should choose the torque characteristics to be good and the
limited class function vector frequency changer. If is the
papermaking, the chemical fiber supposes spare, should choose the high
accuracy, the high response characteristic closed loop vector
frequency changer.
Reliability: Uses the frequency
changer the goal enhances the production efficiency, if the
performance although is good but the reliability not to be good,
frequently has the problem, that gain does not equal the loss.
Our country national territory vast, south local year to year
high temperature moist, the coastal area by the salty corrosion
primarily, these can create the equipment insulation to drop, north
climate dry, is easy to produce the static electricity, the winter
summer temperature difference is big, but also has each enterprise the
production environment is infinitely varied, these factors all are in
select and purchase time the frequency changer should consider.
Some frequency changer performance although very good, but the
environment adaptiveness is bad, has the possibility frequently to
crash the influence production.
In addition, the frequency changer essential component power
module, already generally used the IGBT module and the IPM
intelligence power module, specially IPM module, although the cost was
higher, but because the module interior had has flowed,
short-circuits, owes the pressure, the output earth, protection
function and so on heat, once occurred exceptionally, the module
interior voluntarily protected immediately, then carried on two times
of protections again through exterior protection circuit, burnt the
module the possibility greatly for to reduce, reliable remarkable
enhancement. But uses the GTR module the product, as a result of
the GTR own non- protection function, exterior protection circuit and
the impetus electric circuit is very complex, once protects cannot
follow, the module burns down in a little while. Some factories
in order to reduce the cost, still used the GTR module, this also was
selects and purchases time the frequency changer needed to pay
attention.
Price: This is selects and
purchases when the frequency changer the main consideration factor,
but if one-sidedly pursues the low price, often can cause the quality
and the reliable drop, because in the frequency changer power
component and the host return route electrolysis electric capacity
approximately composes 70% cost, some factories in order to reduce the
cost, replaces 1,200 volts modules with the pressure resistance 1,000
volts modules, replaces 30A with electric current 25A, replaces the
frequency changer special-purpose high frequency electrolysis electric
capacity with the ordinary low frequency electrolysis electric
capacity, this kind of frequency changer uses in the normal condition
or the short time cannot discover has any question, but because the
module power remainder reduced, Once bumps into the electrical
machinery to stop up the extension, the electrical network instant
high voltage, continues situation and so on high temperature, very is
easy to damage.
Post-sale service: The good
product all has the possibility which crashes, the choice has the good
technical strength and the post-sale service production factory or the
dealer, may obtain the thorough technical service, avoids the extra
worries.
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