WEG CFW700 User Manual - page 21

16 | CFW700

Installation and Connection

E

ng

lis

h

ATTENTION!

In order to be able to use the CFW700 with built-in C3 RFI filter (frame sizes A, B, C 

and D with optional RFI filter and all frame size E inverter models – CFW700…C3…) 

in IT networks (neutral conductor not grounded or grounded via a high ohmic value 

resistor) or in corner-grounded delta systems, it is necessary to remove some RFI 

filter components (capacitor for frame sizes A, B, C and D and capacitor and the 

MOV for frame size E) connected to the ground by removing the screws indicated 

in 

Figure A.8 on page 208

 for inverter frame sizes A, B, C and D and changing the 

position of the J1 jumper on the PRT1 board from 

 (XE1) to “NC” (XIT), according 

to the 

Figure A.8 on page 208

 for inverter frame size E.

AC power supply considerations

 Suitable for use on a circuit capable of delivering not more than 100.000 A

rms

 symmetrical 

Ampères at 240 V, 480 V or 600 V maximum, when protected by Class J fuses (for 240 V 

and 480 V models) or special purpose fuses (for 600 V).

3.2.3.2 Dynamic Braking (standard built-in for frame sizes A, B, C and D and 

optional built-in for frame size E - CFW700...DB...)

Refer to 

Table B.1 on page 212

, 

Table B.2 on page 213

 and 

Table B.3 on page 214

 for 

the following dynamic braking specifications: maximum current, resistance, RMS current (*) 

and cable gauges.

The power rating of the dynamic braking resistor is a function of the deceleration time, the load 

inertia and the resistant torque.

Dynamic braking installing procedure:

 Install the braking resistor between the power terminals DC+ and BR.

 Use twisted cable for the connection. Separate these cables from the signal and control 

cables.

 Size the cables according to the application, respecting the maximum and effective currents.

 If the braking resistor is installed inside the inverter cabinet, consider its additional dissipated 

energy when sizing the cabinet ventilation.

The thermal protection of the dynamic braking resistor must be provided externally using a thermal 

relay in series with the resistor and/or a thermostat in contact with the resistor frame, connected 

so as to switch the input power supply of the inverter, as shown in 

Figure 3.3 on page 17

.

Set P0151 and P0185 to their maximum values (400 V or 800 V) when using dynamic braking.

The DC link voltage actuation level of the dynamic braking is set by parameter P0153 (Dynamic 

Braking Level).