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| AUTOMATIC POWER FACTOR CONTROLLERS | |
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Can a digital multimeter record the operating hours of a system? |
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This type of monitoring can be achieved by using one of the LOVATO Electric digital multimeter types DMK20, DMK25, DMK26 and DMK50. The hour counters for the operating hours can be enabled by one of the following conditions:  When a voltage
threshold, programmable by internal parameter Voltage Threshold to activate the hour
counter, is exceeded. When a current
threshold, programmable by internal parameter Current Threshold to activate hour
counter, is exceeded. When both
thresholds, programmable by internal parameters mentioned above, are
exceeded. At power up, whenever no voltage or current threshold has been programmed.The hour counters can be cleared, at any time, by pressing the specific combinations of keys. |
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What does TRMS mean? |
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TRMS
is the acronym of True Root Mean Square. This signifies the measures
are calculated by an algorithm which can determine the average taken
over one complete cycle for a periodic quantity of current or
voltage values, even with harmonic conditions. Contrarily, the measures would be incorrect and unreliable. |
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What does "operating in four quadrants" means? |
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Four-quadrant operation is when equipment
can operate in systems where energy can be imported (consumed)
as well as exported (generated). This is the typical case of co-generation systems, where the displacement angle between voltage and current can vary between 0 and 360°, that is four quadrants. LOVATO Electric equipment, such as: DCRK and DCRJ power factor controllers and the DMK3.., DMK6.. or DMK40 type of multimeters, has efficient and reliable four-quadrant capability. |
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What is weekly PF (Power Factor)? |
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Typically,
weekly PF (Power Factor) is the measurement, adopted by many
electricity boards or energy authorities, to calculate the
efficiency of utility's correction systems for reactive energy,
wherever power factor penalties are imposed. In reality, it is the
average of the power factor values in the last seven days of
operation, monitored by the active-reactive energy meters. |
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What is the difference between cosphi and power factor? |
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Cosphi
or Displacement Power Factor (DPF) is the cosine of the displacement
angle between voltage and current. It is measured and adjusted by power factor controllers like the DCRK. Power factor or Total Power Factor (TPF) is instead the ratio obtained between active power [W] and apparent power [VA]. The power factor value always depends on the cosphi: in particular, both values are equal in a system without harmonics. On the other hand, power factor is lower than cosphi, in presence of harmonics. Power correction boards, consisting of controller and capacitors, cannot correct power factor caused by harmonics but can adjust the cosphi to the required value and obtain, in this way, the best power factor achievable. In circumstances when the power factor is still lower than the set value inspite of the correction of the reactive power to cosphi = 1, it is vital to install harmonic filters to reduce distortions caused by non-linear loads such as motor drives, UPS and so on. |
