Phoenix Contact 1201132, User Manual

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CONTACTRON Speed Starter
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PHOENIX CONTACT 109908_en_00
5.6 Motor cable length
5.6.1 Consequence of leakage current
If the cable length is too long, the stray capacitance between cables increases and may
cause leakage current. In this case, it activates the over-current protection, increases
leakage current, or may affect the current display. The worst case is that it may damage the
CONTACTRON Speed Starter. If more than one motor is connected to one CONTACTRON
Speed Starter, the total wiring length should be the sum of the wiring length from the
CONTACTRON Speed Starter to each motor.
5.6.2 Consequence of the surge voltage
When a motor is controlled by a CONTACTRON Speed Starter, the motor terminals
experience surge voltages ( Δ v / Δ t) due to power transistor conversion of CONTACTRON
Speed Starter. When the motor cable is very long (especially for the 480 V models), surge
voltages ( Δ v / Δ t) may damage the motor insulation and bearing. To prevent this, follow
these rules:
– Use a motor with enhanced insulation.
– Reduce the cable length between the CONTACTRON Speed Starter and motor to
suggested values.
– Connect an output reactor (optional) to the output terminals of the CONTACTRON
Speed Starter.
Refer to the following tables for the suggested motor cable length.
You have to make sure to observe the local EMC standards.
Table 5-2 Maximum motor cable length at 4 kHz carrier frequency (1-phase)
Device type CSS X.XX-1/3 CSS X.XX-
1/3-EMC
Output AC reactor x - -
Input external EMC filter - x -
Output zero-phase reactor - x -
Shielded cable Without EMC category 75 m 50 m 50 m
Category C1 N/A 30 m (CE only) N/A
Category C2 N/A 50 m 20 m
Category C3 N/A 50 m 20 m
Unshielded cable 115 m 75 m 75 m