Danfoss VLT HVAC Drive FC 102 Instruction Manual page 91

How to Program
Current limitations of the Flystart Principle used for PM
motors:
•
The speed range is up to 100% Nominal Speed or
the field weakening speed (which ever is lowest).
•
PMSM with high back emf (>300 VLL(rms)) and
high winding inductance(>10 mH) needed more
time for reducing short circuit current to zero and
may be susceptible to error in estimation.
•
Current testing limited to a speed range up to
300 Hz. For certain units, the limit is 250 Hz; all
200‒240V units up to and including 3 HP [2.2
kW] and all 380‒480V units up to and including
5.4 HP [4 kW].
•
Current testing limited to a machine power size
up to 30 HP [22 kW].
•
Prepared for salient pole machine (IPMSM) but
not yet verified on those types of machine.
•
For high inertia applications (i.e., where the load
inertia is more than 30 times larger than the
motor inertia), a brake resistor is recommended
to avoid overvoltage trip during high speed
engagement of the Flystart function.
1-80 Function at Stop
Option: Function:
Select the adjustable frequency drive function
after a stop command or after the speed is
ramped down to the settings in
parameter 1-81 Min Speed for Function at Stop
[RPM].
Available selections depend on
parameter 1-10 Motor Construction:
[0] Asynchron:
[0] coast
[1] DC hold
[2] Motor check, warning
[6] Motor check, alarm
[1] PM non-salient:
[0] coast
[0] Coast Leaves motor in free mode.
*
[1] DC Hold/ Energizes motor with a DC holding current (see
Motor parameter 2-00 DC Hold/Preheat Current).
Preheat
[2] Motor Issues a warning if the motor is not connected.
check,
warn.
[6] Motor Issues an alarm if the motor is not connected.
check,
alarm
MG11F522
Instruction Manual
1-90 Motor Thermal Protection
Option:
[0] No
protection
[1] Thermistor
warning
[2] Thermistor
trip
[3] ETR warning
1
[4] ETR trip 1
[5] ETR warning
2
[6] ETR trip 2
[7] ETR warning
3
[8] ETR trip 3
[9] ETR warning
4
[10] ETR trip 4
ETR (Electronic Thermal Relay) functions 1-4 will calculate
the load when the set-up where they were selected is
active. For example, ETR-3 starts calculating when set-up 3
is selected. For the North American market: The ETR
functions provide class 20 motor overload protection in
accordance with NEC.
Danfoss A/S © 08/2014 All rights reserved.
Function:
The adjustable frequency drive determines
the motor temperature for motor protection
in two different ways:
•
Via a thermistor sensor connected
to one of the analog or digital
inputs (parameter 1-93 Thermistor
Source).
•
Via calculation (ETR = Electronic
Thermal Relay) of the thermal load,
based on the actual load and time.
The calculated thermal load is
compared with the rated motor
current I and the rated motor
M,N
frequency f . The calculations
M,N
estimate the need for a lower load
at lower speed due to less cooling
from the fan incorporated in the
motor.
If the motor is continuously overloaded and
no warning or trip of adjustable frequency
drive is wanted.
Activates a warning when the connected
thermistor in the motor reacts in the event of
motor overtemperature.
Stops (trips) the adjustable frequency drive
when the connected thermistor in the motor
reacts in the event of motor overtem-
perature.
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