Oriental motor BLVD20KM - Page 7

Precautions for use
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Noise elimination measures
The electrical noise is of two types: One is a noise to invade into the driver from the outside and cause the driver
malfunction, and the other is a noise to emit from the driver and cause peripheral equipment malfunction.
For the noise that is invaded from the outside, take measures to prevent the driver malfunction. It is needed to take
adequate measures because signal lines are very likely to be aected by the noise.
For the noise that is emitted from the driver, take measures to suppress it.
Refer to p.21 for "Installing and wiring in compliance with EMC Directive."
Measures against electrical noise
There are the following three methods mainly to take measures against the electrical noise.
•
Noise suppression
•
When relays or electromagnetic switches are used, use noise lters or CR circuits to suppress surge generated by
them.
•
Use the connection cable for the exclusive use of the
BLV
series when extending the wiring distance between the
motor and driver. This is eective in suppressing the electrical noise emitted from the motor.
•
Cover the driver by a metal plate such as aluminum. This is eective in shielding the electrical noise emitted from
the driver.
•
Prevention of noise propagation
•
Separate power lines such as motor cable and power supply cable from signal lines for a distance of 100 mm (3.94in.)
or more, and also do not bundle them or wire them in parallel. If the power lines must cross over the signal lines,
wire them at right angles.
•
For more eective elimination of noise, use a shielded I/O signal cable or attach ferrite cores if a non-shielded cable
is used.
•
Keep cables as short as possible without coiling and bundling extra lengths.
•
To ground a shielded cable, use a metal cable clamp that can maintain
contact with the entire circumference of the shielded cable, and ground
as near the product as possible.
Cable clamp
Shielded cable
•
Grounding multiple points will increase eect to block electrical noise because impedance on the grounding points
is decreased. However, ground them so that a potential dierence does not occur among the grounding points.
•
Suppression of eect by noise propagation
•
Loop the noise propagated cable around a ferrite core. Doing so will prevent the propagated noise invades into the
driver or emits from the driver. The frequency band in which an eect by the ferrite core can be seen is generally
1MHz or more.
Check the frequency characteristics of the ferrite core used. When increasing the eect of noise attenuation by the
ferrite core, loop the cable a lot.