30–90 kW
Figure 2.26 Galvanic Isolation
1 Power supply (SMPS) incl. signal isolation of UDC, indicating
the intermediate current voltage
2 Gate drive that runs the IGBTs (trigger transformers/opto-
couplers)
3 Current transducers
4 Internal soft-charge, RFI and temperature measurement
circuits
5 Custom relays
a Control card terminals
Table 2.24 Legend to Figure 2.26
The functional galvanic isolation (see Figure 2.25) is for the
RS-485 standard bus interface.
CAUTION
Installation at high altitude:
At altitudes above 6,600 ft [2 km], contact Danfoss
regarding PELV.
2.10 Ground Leakage Current
WARNING
DISCHARGE TIME
Touching the electrical parts could be fatal - even after
the equipment has been disconnected from line power.
Also make sure that other voltage inputs have been
disconnected, such as load sharing (linkage of DC
intermediate circuit), as well as the motor connection for
kinetic backup.
Before touching any electrical parts, wait at least the
amount of time indicated in the Table 2.1.
Shorter time is allowed only if indicated on the
nameplate for the specific unit.
NOTICE!
Leakage Current
The ground leakage current from the adjustable
frequency drive exceeds 3.5 mA. To ensure that the
ground cable has a good mechanical connection to the
ground connection, the cable cross-section must be at
least 10 mm
2
Cu or 16 mm
2
Al or two rated ground
wires terminated separately.
Residual Current Device protection RCD
This product can cause a DC current in the protective
conductor. Where a residual current device (RCD) is used
for protection in case of direct or indirect contact, only
an RCD of Type B is allowed on the supply side of this
product. Otherwise, another protective measure must be
applied, such as separation from the environment by
double or reinforced insulation, or isolation from the
supply system by a transformer. See also Application
Note Protection against Electrical Hazards, MN90G.
Protective grounding of the adjustable frequency drive
and the use of RCDs must always follow national and
local regulations.
2.11 Extreme Running Conditions
Short circuit (motor phase – phase)
Current measurement in each of the three motor phases or
in the DC link, protects the adjustable frequency drive
against short circuts. A short circuit between two output
phases causes an overcurrent in the inverter. The inverter
is turned off individually when the short circuit current
exceeds the permitted value (Alarm 16 Trip Lock).
To protect the adjustable frequency drive against a short
circuit at the load sharing and brake outputs see the
design guidelines.
Switching on the output
Switching on the output between the motor and the
adjustable frequency drive is fully permitted. The
adjustable frequency drive is not damaged in any way by
switching on the output. However, fault messages may
appear.
Motor-generated overvoltage
The voltage in the intermediate circuit is increased when
the motor acts as a generator. This occurs in following
cases:
1. The load drives the motor (at constant output
frequency from the adjustable frequency drive),
that is the load generates energy.
Product Overview
Design Guide
42 Danfoss A/S © Rev. 2014-01-14 All rights reserved. MG18C522
22
To Next Page
Loading...
Need help?
General