ABB ACS880-34 - Protecting the Motor Insulation and Bearings; Requirements Table

Guidelines for planning the electrical installation 59
 Protecting the motor insulation and bearings
The drive uses modern IGBT inverter technology. Regardless of frequency, the drive
output has pulses of approximately the drive DC bus voltage with a very short rise time. Up
to twice bus voltage can be at the motor terminals, depending on the attenuation and
reflection properties of the motor cable and the terminals. The increased voltage can
cause additional stress on the motor and motor cable insulation.
Modern variable speed drives with their fast rising voltage pulses and high switching
frequencies can generate current pulses that flow through the motor bearings. This can
gradually erode the bearing races and rolling elements.
Optional du/dt filters protect motor insulation system and reduce bearing currents.
Optional common mode filters mainly reduce bearing currents. Insulated N-end (non-drive
end) bearings protect the motor bearings.
 Requirements table
The following table shows how to select the motor insulation system and when optional
ABB du/dt filters, insulated N-end (non-drive end) motor bearings and ABB common mode
filters are required. Failure of the motor to fulfill the following requirements or improper
installation may shorten motor life or damage the motor bearings and voids the motor
warranty.
Motor
type
Nominal AC supply
voltage
Requirement for
Motor
insulation
system
ABB du/dt and common mode filters, insulated N-end
motor bearings
100 kW <
P
N
< 350 kW
or
IEC 315 <
frame size <
IEC 400
P
N
> 350 kW
or
frame size >
IEC 400
134 hp <
P
N
< 469 hp
or
NEMA 500 <
frame size <
NEMA 580
P
N
> 469 hp
or
frame size > NEMA 580
ABB motors
Random
-wound
M2_,
M3_ and
M4_
U
N
< 500 V Standard + N + N + CMF
500 V < U
N
< 600 V Standard + N + du/dt + N + du/dt + CMF
or
Reinforced + N + N + CMF
600 V < U
N
< 690 V
(cable length < 150 m)
Reinforced + N + du/dt + N + du/dt + CMF
600 V < U
N
< 690 V
(cable length > 150 m)
Reinforced + N + N + CMF
Form-
wound
HX_ and
AM_
380 V < U
N
< 690 V Standard + N + CMF P
N
< 500 kW:
+N + CMF
P
N
> 500 kW
+N + du/dt + CMF
Old*
form-
wound
HX_ and
modular
380 V < U
N
< 690 V Check with
the motor
manufacturer.
+ N + du/dt with voltages over 500 V + CMF