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Chapter 1 Introduction| BLD-E1 Series
Revision May 2009, 00DE, V0.50 1-5
RFI Jumper
RFI Jumper: The brushless DC motor drive may emit the electrical noise. The EMI(electromagnetic
interference with standard Y capacity) is used to suppress the interference (Radio Frequency
Interference) on the power line. As the leakage current will be increased after using with EMI, user
can cut off the RFI when reducing the leakage current is required.
Main power isolated from earth:
If the brushless DC motor drive is supplied from an isolated power (IT power), the RFI jumper must
be cut off. Then the RFI capacities (filter capacitors) will be disconnected from ground to prevent
circuit damage (according to IEC 61800-3) and reduce earth leakage current.
CAUTION!
1. After applying power to the brushless DC motor drive, do not cut off the RFI jumper. Therefore,
please make sure that main power has been switched off before cutting the RFI jumper.
2. The gap discharge may occur when the transient voltage is higher than 1,000V. Besides,
electro-magnetic compatibility of the brushless DC motor drives will be lower after cutting the
RFI jumper.
3. Do NOT cut the RFI jumper when main power is connected to earth.
4. The RFI jumper cannot be cut when Hi-pot tests are performed. The mains power and motor
must be separated if high voltage test is performed and the leakage currents are too high.
5. To prevent drive damage, the RFI jumper connected to ground shall be cut off if the brushless
DC motor drive is installed on an ungrounded power system or a high impedance grounding
(over 30 ohms) power system or a corner grounded TN system.
About Grounding System
According to international standard IEC60364, the grounding system can be divided as follows:
1. The first letter: the connection between grounded point and power equipment (generator or
transformer)
T: connect to the same grounded point directly, I: NOT connect to the grounded point
(insulation) or grounded via high-resistance equipment.
2. The second letter: connection method between grounded point and the electrical device being
supplied
T: connect to grounded point, independent of other power supplied grounded point, N:
grounded via the power supply system
3. The third and forth letter: position of grounded conductor
S: neutral and grounded point are disconnection, C: neutral is connected to grounded point in
parallel