Chapter 3 Mechanical and Electrical Installation
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•
The cable length of the braking unit must not exceed 10 m. Use twisted pair wire or tight pair wires for
parallel connection.
•
Do not connect the braking resistor directly to the DC bus. Otherwise, it may damage the AC drive and
even cause a re.
3. Terminals (+), BR for connecting braking resistor
•
For the AC drive of 75 kW and below with the built-in braking unit, terminals (+) and BR are effective.
•
Select a braking resistor of the recommended value and ensure that the cable length of the braking
resistor must be shorter than 5 m. Otherwise, it may cause damage to the AC drive.
4. AC drive output terminals U, V, W
•
The specification and installation method of external power cables must comply with the local safety
regulations and related IEC standards.
•
Use copper conductors of a proper size as power cables according to the recommended values in section
8.3.
•
Do not connect a capacitor or surge absorber to the output side of the AC drive. Otherwise, it may cause
frequent AC drive fault or even damage the AC drive.
•
If the motor cable is too long, electrical resonance will be generated due to the impact of distributed
capacitance. This will damage the motor insulation or generate higher leakage current, causing the AC
drive to trip in overcurrent protection. If the motor cable is greater than 50 m long, an AC output reactor
must be installed close to the AC drive.
5. Terminal PE
•
The terminal must be reliably grounded and the resistance of the grounding wire must be less than 10 Ω.
Otherwise, it may cause abnormal running or even damage to the AC drive.
•
Do not connect this terminal to the neutral conductor of the power supply.
•
The impedance of the PE conductor must be able to withstand the large short-circuit current that may
arise when a fault occurs.
•
Select the size of the PE conductor according to the following table.
Table 3-3 Dimensions of the protection grounding conductor
Cross-sectional Area of a Phase Conductor (S) Min. Cross-sectional Area of Protective Conductor (Sp)
S ≤ 16 mm
2
S
16mm
2
< S ≤ 35 mm
2
16 mm
2
35 mm
2
< S S/2
You must use a yellow/green cable as the PE conductor.
6. Requirements on upstream protection device
•
Install a proper protection device on the power input side to provide protections on overcurrent, short-
circuit and electrical isolation.
•
When selecting the protection device, you should consider the current capacity of the power cable,
system overload capacity and short-circuit capacity of the equipment upstream power distribution.
Generally, make selection according to the recommended values in section 7.7.
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