Danfoss Mci Soft-Start Controller - Danfoss SH090 Application Manuallines

Application Guidelines
Max. operating Current
Winding resistance
Danfoss MCI soft-start
controller
Input controlled soft start
Electrical data, connections and wiring
The max. operating current is the current when
the compressor operates at maximum load
conditions and 10% below nominal voltage
(+15°C evaporating temperature and +68°C
condensing temperature).
Winding resistance is the resistance between
phases at 25°C (resistance value +/- 7%).
Winding resistance is generally low and it
requires adapted tools for precise measurement.
Use a digital ohm-meter, a "4 wires" method and
measure under stabilised ambient temperature.
Winding resistance varies strongly with winding
temperature. If the compressor is stabilised
at a different value than 25°C, the measured
resistance must be corrected using following
formula:
The inrush current for the Danfoss SH scroll
compressors with motor code 4 (400V /3ph
/ 50Hz or 460V / 3ph / 60Hz) can be reduced
using the Danfoss soft starter. MCI and MCD
soft starters are designed to reduce the
Compressor model
SH090
SH105-120
SH140-161
SH180-SH184
SH240
SH295-380
SH485
* by-pass contactor K1 is required
Upon starting, the controller gradually increases
the voltage supplied to the motor until full-line
voltage has been reached.
For MCI15C, MCI25C and MCI50M, all settings
such as initial torque, ramp-up time (less than
0.5 sec) and ramp-down time are preset and do
not require any modification.
U
ramp-up
ramp-down
Initial torque
When the control voltage is applied to A1 - A2,
the MCI soft starter will start the motor, according
to the settings of the ramp-up time and initial
torque adjustments. When the control voltage
is switched OFF, the motor will switch off
instantaneously.
Max Oper. A can be used to select cables and
contactors.
In normal operation, the compressor current
consumption is always less than the Max Oper. A.
value.
a + t
amb
R = R _______
tamb 25°C
a + t
25°C
t : reference temperature = 25°C
25°C
t : temperature during measurement (°C)
amb
R : winding resistance at 25°C
25°C
R : winding resistance at tamb
amb
Coefficient a = 234.5
starting current of 3-phase AC motors; they
can reduce the inrush current by up to 40%,
thereby eliminating the detrimental effects of
high starting torque surges and costly demand
charges from the resultant current spike.
Soft start reference
Ambient max. 40°C
MCI15C
MCI25C
MCI25C
MCI50CM
MCI50CM
MCI50CM *
MCD201-055
For MCD201-055, the following settings have to
be adjusted to ensure a maximum inrush current
reduction as well as a starting time less than
0.5 sec.
Frequency Initial
torque
(%U)
50 Hz 60%
60 Hz 70%
Time
Soft start reference
Ambient max. 55°C
MCI15C
MCI25C
MCI25C *
MCI50CM
MCI50CM *
MCI50CM *
MCD201-055
Ramp-up Ramp
(seconds) down
(seconds)
2 0
0.5 0
AB243586442172en-001301
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