Additional Connections - Danfoss FC 300 Design Manual

8 Electrical Installation

8.7 Additional Connections

8.7.1 DC Bus Connection
The DC bus terminal is used for DC back-up, with the intermediate circuit being supplied from an external source.
Terminal numbers used: 88, 89
Please contact Danfoss if you require further information.
8.7.2 Load Sharing
Terminal No.
88, 89
The connection cable must be screened and the max. length from the frequency converter to the DC bar is limited to 25 metres (82 feet).
Load sharing enables linking of the DC intermediate circuits of several frequency converters.
8
Please note that voltages up to 1099 VDC may occur on the terminals.
Load Sharing calls for extra equipment and safety considerations. For further information, see load sharing Instructions MI.50.NX.YY.
Please note that mains disconnect may not isolate the frequency converter due to DC link connection
8.7.3 Installation of Brake Cable
The connection cable to the brake resistor must be screened and the max. length from the frequency converter to the DC bar is limited to 25 metres (82
feet).
1. Connect the screen by means of cable clamps to the conductive
back plate on the frequency converter and to the metal cabinet
of the brake resistor.
2. Size the brake cable cross-section to match the brake torque.
See Brake instructions, MI.90.FX.YY and MI.50.SX.YY for more information about safe installation.
NB!
If a short circuit in the brake IGBT occurs, prevent power dissipation in the brake resistor by using a mains switch or contactor to
disconnect the mains for the frequency converter. Only the frequency converter shall control the contactor.
Please note that voltages up to 1099 VDC, depending on the supply voltage, may occur on the terminals.
186
Function
Loadsharing
MG.33.BC.02 - VLT ®
No. Function
81, 82 Brake resistor terminals
is a registered Danfoss trademark
FC 300 Design Guide