Motor Insulation; Motor Bearing Currents; Brake Resistor Temperature Switch; Control Cable Routing - Danfoss VLT AQUA Drive FC 202 Operating Instructions Manual

How to Install

4.1.13 Motor Insulation

For motor cable lengths ≤ the maximum cable length
listed in , the motor insulation ratings in Table 4.19 are
recommended. Peak voltage can be up to twice the DC-
link voltage, and 2.8 times the mains voltage, due to
transmission line effects in the motor cable. If a motor has
lower insulation rating, use a dU/dt or sine-wave filter.
Nominal mains voltage [V] Motor insulation [V]
≤ 420
U Standard U
N
420 < U ≤ 500 Reinforced U
N
500 < U ≤ 600 Reinforced U
N
600 < U ≤ 690 Reinforced U
N
Table 4.19 Motor Insulation Ratings

4.1.14 Motor Bearing Currents

All motors installed with FC 202 315kW or higher power
drives should have NDE (Non-Drive End) insulated bearings
installed to eliminate circulating bearing currents. To
minimize DE (Drive End) bearing and shaft currents proper
grounding of the drive, motor, driven machine, and motor
to the driven machine is required.
Standard Mitigation Strategies:
1. Use an insulated bearing
2. Apply rigorous installation procedures
- Ensure the motor and load motor are
aligned
- Strictly follow the EMC Installation
guideline
- Reinforce the PE so the high frequency
impedance is lower in the PE than the
input power leads
- Provide a good high frequency
connection between the motor and the
frequency converter for instance by
screened cable which has a 360°
connection in the motor and the
frequency converter
- Make sure that the impedance from
frequency converter to building ground
is lower that the grounding impedance
of the machine. This can be difficult for
pumps
- Make a direct earth connection between
the motor and load motor
3. Lower the IGBT switching frequency
4. Modify the inverter waveform, 60° AVM vs.
SFAVM
MG20Y202
Operating Instructions

4.1.15 Brake Resistor Temperature Switch

=1300
LL
=1600
LL
=1800
LL
=2000
LL
This input can be used to monitor the temperature of an
externally connected brake resistor. If the input between
104 and 106 is established, the frequency converter trips
on warning/alarm 27 Brake IGBT. If the connection is closed
between 104 and 105, the frequency converter trips on
warning/alarm 27 Brake IGBT.
Install a KLIXON switch that is normally closed. If this
function is not used, short-circuit 106 and 104 together.
Terminal number
106, 104, 105
Table 4.20 Brake Resistor Temperature Switch Terminals
If the temperature of the brake resistor gets too high
and the thermal switch drops out, the frequency
converter stops braking and the motor starts coasting.
Illustration 4.15 Brake Resistor Temperature Switch

4.1.16 Control Cable Routing

Tie all control wires down to the designated control cable
routing. Remember to connect the shields in a proper way
to ensure optimum electrical immunity.
Fieldbus connection
Connections are made to the relevant options on the
control card. For details, see the relevant fieldbus
instruction. Place the cable in the provided path inside the
Danfoss A/S © Rev. 06/2014 All rights reserved.
5. Install a shaft grounding system or use an
isolating coupling
6. Apply conductive lubrication
7. Use minimum speed settings if possible
8. Try to ensure the line voltage is balanced to
ground. This can be difficult for IT, TT, TN-CS or
Grounded leg systems
9. Use a dU/dt or sinus filter
•
Torque: 0.5-0.6 Nm (5 in-lbs)
•
Screw size: M3
•
Normally closed: 104-106 (factory installed
jumper)
•
Normally open: 104-105
Function
Brake resistor temperature switch.
CAUTION
106 104 105
NC C NO
4 4
41