ABB ACS880-07CLC, Руководство по оборудованию

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2. P
br
≤ P
brmax
Number of braking pulses during a 10-minute period n
Maximum braking power (kW) for a custom braking cycle P
br
Braking time (s) t
br
Maximum braking power for a reference braking cycle (1 minute of braking, 9 minutes of rest) P
brmax
Example 1
The duration of a braking cycle is 30 minutes. The braking time is 15 minutes.
Result: If the braking time exceeds 10 minutes, the braking is considered continuous. The
allowed continuous braking power is 10% of maximum braking power ( P
brmax
).
Example 2
The duration of a braking cycle ( T ) is three minutes. The braking time ( t
br
) is 40 seconds.
1. n × P
br
× t
br
≤ P
brmax
× 60 s => P
br
≤ ( P
brmax
× 60 s) / (4 × 40 s) = 0.375 × P
brmax
2. P
br
≤ P
brmax
<=> 0.375 × P
brmax
≤ P
brmax
OK
Result: The maximum braking power for the custom braking cycle is 37% of the rated value
given for the reference cycle.
￭ Selecting and routing the cables of a custom resistor
Use the same cable type for the resistor cabling as for the drive input cabling to ensure that
the input fuses also protect the resistor cable. Alternatively, a two conductor shielded cable
with the same cross-sectional area can be used.
Minimizing electromagnetic interference
Follow these rules in order to minimize electromagnetic interference caused by the rapid
current changes in the resistor cables:
• Shield the braking power line completely, either by using shielded cable or a metallic
enclosure. Unshielded single-core cable can only be used if it is routed inside a cabinet
that efficiently suppresses the radiated emissions.
• Install the cables away from other cable routes.
• Avoid long parallel runs with other cables. The minimum parallel cabling separation
distance should be 0.3 meters (1 ft).
• Cross any other cables at right angles.
• Keep the cable as short as possible in order to minimize the radiated emissions and
stress on chopper IGBTs. The longer the cable the higher the radiated emissions,
inductive load and voltage peaks over the IGBT semiconductors of the brake chopper.
Note:
ABB has not verified that the EMC requirements are fulfilled with custom brake resistors
and cabling. The customer must consider the EMC compliance of the complete installation.
Maximum cable length
The maximum length of the resistor cable(s) is 50 m (164 ft).
￭ Placing custom brake resistors
Install the resistors outside the drive in a place where they are able to cool effectively.
Arrange the cooling of the resistor in a way that
Resistor braking 207