Motor Thermal Protection; Motor Cable Length - KEB COMBIVERT F5 Instruction Manual

1.4.6 Motor Thermal Protection
The F5 series inverters are UL approved as a solid state motor overload protec-
tion device. It is necessary to adjust the current trip level in parameter LF. or
LF.12. The function assumes the use of a non-ventilated motor. The function
meets the requirements set forth in VDE 0660 Part 104, UL508C section 42,
NFPA 70 Article 430 part C. See the description for parameter LF. for the trip
characteristics.
A motor winding sensor can also be used for additional safety and the highest
level of protection. Either a normally closed contact (rating: 15V / 6mA) or a PTC
(positive temperature coefficient) resistor can be connected to the T1, T2 termi-
nals on the inverter. The thermal device should be connected as indicated on
page 24.
1.4.7 Motor Cable Length
In some conventional installations and many MRL applications, the motor can
be a considerable distance (greater then 40 feet) from the elevator drive. Under
these circumstances the long cable length can cause high voltage peaks or high
dv/dt (rate of voltage rise) on the motor windings. Depending on the design of the
motor, these can lead to damage of the motor winding. Therefore, in these instal-
lations use of a special dv/dt filter is highly recommended.
The standard approved solution is special output choke designed for use with the
a maximum of 16kHz switching frequency and low inductance so as not to drasti-
cally influence the motor's equivalent circuit model.
There are three sizes available for motors rated up to 136A. The part numbers
and current ratings are listed below.
Part Number
18Z1A05-1000
21Z1A05-1000
23Z1A05-1000
The use of a conventional line or motor choke on the output of the drive is not
recommend since the inductance value is high enough that it would distort the
values in the motor model and result in poor control of the motor.
Rated Current
45A
75A
136A
General
15