12
12. Countermeasure against Noise
12-1. Noise Filter & Condition for CE Marking
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Noise Filter
Frequency components of noise generated by the thyristors are distributed in the
areas of a few megahertz or lower. Universal noise filters available on the market
do not have sufficient effect to reduce such noise.
It is possible to reduce such noise when the following our designated noise filter is
used.
The filter is specified for use in our thyristor power regulators.
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Condition for CE Marking
CAUTION
When the product is used with noise filter and wired as specified by the instruction manual, the product meets the requirement of EMC command.
1. For dealing with EMC command
Use in combination with a noise filter designed by us. Install the noise filter on the same metal plate as the PAC27. Do not forget to properly
ground it.
The length of wiring between the noise filter and the PAC27 should be 0.5m or less.
2. For dealing with low-voltage command
When power line is wired, as a precaution against accidental short-circuit, make sure to install one molded case circuit breaker for each PAC27.
The current capacity of a molded case circuit breaker should be 1.3 times lower than that of the PAC27.
12-2. Power Waveform Distortion Improvement by Power Capacitor
To connect a power capacitor for power-factor improvement across the main terminals R and T of the PAC27 is an effective method to improve
power distortion (higher harmonics).
The effect is recognized at a rate of 1μF capacitor capacity to about 1A current capacity.
Although the method is simple, attention should be paid to the following points:
1. Close attention should be paid to the rated current of the capacitor and a rise in temperature since a higher harmonic current flows into the
capacitor.
2. The capacitor may produce higher harmonic voltage through its resonance with the power supply line inductance. Check the power waveforms.
Type
Current capacity
NF2030C-SDG
30A
NF2050C-SDG
45A
NF2060C-SDG
60A
NF2080C-SDG
80A
NF2100C-SDG
100A
Manufacturer: Soshin Denki K.K
